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OPERATIONS PROTOCOL FOR ECO-EFFICIENT WOOD HARVESTING ON SENSITIVE SITES
Owende, P.M.O., Lyons, J. and S.M. Ward (Editors)
Contributing authors Owende, P.M.O., Lyons, J., Haarlaa, R., Peltola, A., Spinelli, R., Molano, J and S.M. Ward
December, 2002
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Funded under the European Union Fifth Framework Programme on the Quality of Life and Management of Living Resources Contract No. QLK5-1999-00991(1999-2002) This document was developed by the ECOWOOD Partnership (see next page).
© ECOWOOD Partnership, 2002 This Operations Protocol (OP) is intended as a guide for machinery selection and operation on sensitive sites and is to be used with the existing Codes of Best Forest Practice. Its application will require personal judgement and the ECOWOOD Partnership does not accept responsibility for any decisions made, and their consequences.
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Ecowood Partnership 1. University College Dublin (Co-ordinating Partner) Forest Engineering Unit, Dept. of Agricultural and Food Engineering, University College Dublin, Earlsfort Terrace, Dublin 2, IRELAND Contact: Professor Shane M. Ward Tel.: (+353 1) 716 7351 Fax: (+353 1) 475 2119 e-mail: [email protected] or [email protected] www.ucd.ie/~foresteng 2. Coillte Teoranta Sullivan's Quay, Cork, IRELAND Contact: Mr John Lyons, Tel.: (+353 21) 4964 366 Fax: (+353 21) 4964 072 e-mail: [email protected] 3. Consiglio Nazionale Delle Ricerche (CNR) Instituto Per la Ricerca Sul Legno, Via Barazzuoli 23, I-50136,Florence, ITALY Contact: Mr Raffaele Spinelli, Tel.: (+39 055) 661 886 Fax: (+39 055) 670 624 e-mail: [email protected]
4. University of Helsinki Department of Forest Resource Management, Unioninkatu 40 B // P. O. Box 24, FIN - 00014 University of Helsinki, Helsinki, FINLAND Contact: Prof. Rihko Haarlaa, Tel.: (+358 9) 191 7651 Fax: (+358 9) 191 7755 e-mail: mailto:[email protected] 5. Servicios Forestales S.L. (SEFO) Pasaje Virgen De Regla, 1, E - 41011 Sevilla, SPAIN. Contact: Mr Julio Molano, Tel.: (+34 95) 599 9960 Fax: (+34 95) 599 9961 e-mail: [email protected] 6. Plustech OY Lokomonkatu 15 // P. O. Box 306, FIN - 33101 Tampere, FINLAND Contact: Mr Antti Peltola, Tel.: (+358 205) 846 816 Fax: (+358 205) 846 849 e-mail: [email protected]
Quality Assurance Group (QAG) Dr Eugene Hendrick, Director, COFORD, UCD, Belfield, Dublin 4, Ireland. Phone: + 353 1 716 7665; Fax : + 353 1 716 1180; e-mail: [email protected] Dr Dietmar Matthies, Lehrstuhl fuer Forstliche Arbeitswissenschaft und Angewandte Informatik, Arbeitsgruppe Bodenphysik und Bodenmechanik, Am Hochanger 13, 85354 Freising, Germany. Phone: + 49 81 61 714 768; Fax: +49 08161 714 767; e-mail: [email protected] Mr Pieter D. Kofman, Danish Forest and Landscape Research Institute, Kvak Mollevej, DK 7100 Vejle, DENMARK. Phone: +45 75 882 211; Fax: +45 75 882 085; e-mail: [email protected]
ECOWOOD Web Site: www.ucd.ie/~foresteng
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Foreword
Mechanised timber harvesting is central to the sustainable management of Europe’s forests. Such operations must be carried out with minimal impact on the environment and in a cost effective manner. The risks of environmental damage are most pronounced on sensitive sites. Such sites include the soft peat and gley soils of North Western Europe, and the sandy soils on steep slopes in Southern Europe along the Mediterranean. The latter areas are also prone to soil erosion during periods of heavy rainfall and particular care has to be taken to ensure that the mechanisation system employed does not exacerbate this risk. Repeated trafficking of sites by heavy machinery can lead to soil compaction, excessive rutting and root damage, and excessive rutting can produce a network of conduits for surface water flow into local streams and lakes. Modern timber harvesting machines are equipped with sophisticated on-board electronic systems (including GPS, GIS, production monitors and telemetric data transfer from the machine to the office). These can also be used to plan, monitor and control harvesting operations in order to enhance operational efficiency and minimise environmental impacts. For example, machine routing within the forest can be controlled to minimise the likelihood of excessive rutting while also enhancing operational efficiency to minimise costs. This Operations Protocol (OP) sets out recommendations for machinery selection and operation on sensitive sites. It draws on both the available scientific literature and a three-year programme of research carried out under the ECOWOOD project. It is based on an eclectic selection of the state-of-the-art timber harvesting machines and harvesting operation techniques. The OP is designed to be readily implemented at operational level. It is envisaged that it will complement existing codes of best practice and play a central role in Sustainable Forest Management (SFM) on sensitive sites in Europe. ----------------------------- Dr Eugene Hendrick Director Coford (Council for Forest R & D) UCD Dublin 4 IRELAND
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Table of Contents
Table of Notation ....................................................................................................................................7
1 Introduction ....................................................................................................................................8
1.1 Definition of sensitive sites...................................................................................................9 1.2 Machinery for mechanised timber harvesting ...................................................................9 1.3 Classification of site damage .............................................................................................10 1.4 Purpose and applications of this protocol .......................................................................11
2 Matching machines to sites ..........................................................................................................13
2.1 Introduction ..........................................................................................................................13 2.2 Terrain Classification .........................................................................................................13
2.2.1 Ground condition............................................................................................................13 2.2.2 Ground roughness...........................................................................................................15 2.2.3 Slope ...............................................................................................................................15
2.3 Soil-machine interaction.....................................................................................................15 2.3.1 Nominal Ground Pressure (NGP)..............................................................................15 2.3.2 Soil Rutting.....................................................................................................................16 2.3.3 Damage to roots..............................................................................................................18 2.3.4 Soil Erosion ....................................................................................................................19 2.3.5 Example of machinery system selection.........................................................................20
2.4 Consequences of mismatching machines to harvest sites .......................................................20 2.4.1 Soil compaction and rutting............................................................................................20 2.4.2 Machine immobilisation .................................................................................................22
2.5 Cost considerations ................................................................................................................23
3. Machine Telemetrics ....................................................................................................................26
3.1 Rationale for integrated logistics in procurement of wood ....................................................26 3.2 Mechanisation systems for wood harvesting ..........................................................................27 3.3 Requirements for telemetric data transfer ..............................................................................27 3.4 Operational benefits ...............................................................................................................29 3.5 Environmental benefits ...........................................................................................................29 3.6 Recommendations...................................................................................................................29
4 Recommended Practice................................................................................................................30
4.1 General recommendations......................................................................................................30 4.2 Site specific recommendations................................................................................................30 4.3 Machinery Selection ...............................................................................................................30
4.3.1 Site factors ......................................................................................................................30 4.3.2 Machine types.................................................................................................................31 4.3.3 Effective Use of Brash....................................................................................................33
4.4 Management Considerations ........................................................................................................35 4.4.1 Management of watercourse crossings and site drainage structures...............................35 4.4.2 Forest road maintenance .................................................................................................36
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4.4.3 Landing Area ..................................................................................................................36 4.4.4 Environmental Pollution.................................................................................................38 4.4.5 Operations monitoring ....................................................................................................41
4.5 Selection and operation of cable systems on sensitive sites....................................................43 4.6 Socio-economic considerations ..............................................................................................48
Bibliography..........................................................................................................................................51
Appendix 1: Specifications for some commercially available forest harvesters and forwarders ..61
Appendix 2: Calculated Nominal Ground Pressures (NGP) for a range of forest machines.........66
Addendum: General Statistics on Forestry Operations in the ECOWOOD Partnership Countries (Finland, Ireland, Italy and Spain) .....................................................................................................68
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TABLE OF NOTATION Band Tracks Usually a construction of chained metal shoes placed around the bogies of a machine on rubber tyres to increase traction and give extra flotation. Brash The portion of a tree (stem or branches) with a diameter below the minimum set for utilisation (typically less than 70 mm). A Brash Mat is where a layer of brash has been laid down on the forest floor to minimise damage by machine traffic. CI Cone Index CTL Cut-To-Length (CTL) Cutting In timber harvesting a compound term referring to the operations of felling, delimbing, debarking and bucking Dbh Diameter at breast height DSS Decision Support System FOPS Falling Object Protective Structures Forwarding Transporting trees or logs by carrying them completely in the air rather than pulling or dragging them along the ground. GBC Ground Bearing Capacity Harvesting The aggregation of all operations including harvest planning and post-harvest assessment related to the felling of trees and the extraction of their stems or other usable parts from the forest for subsequent processing into industrial
products. This is also referred to as timber harvesting. H-GBC High Ground Bearing Capacity L-GBC Low Ground Bearing Capacity Trail/Strip road/Forwarding track A planned primary transport route within the forest where the trees obstructing the transport are removed. M-GBC Medium Ground Bearing Capacity NGP Nominal Ground Pressure OP Operations Protocol PMH Productive Man Hour RSI Repetitive Strain Injury Trafficking Repeated machine movement over the soil. Smearing/Slurrying Complete breakdown of the soil structure resulting in a liquid slurry of soil and water SFM Sustainable Forest Management WBV Whole Body Vibration Yarder Timber extraction system consisting of a tower, set of winch drums, power source prime mover which is able to winch logs (up or down hill) in a partly or fully elevated state.
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1 INTRODUCTION Timber harvesting is the integration of all operations related to the cutting of trees and the extraction of merchantable wood for subsequent processing into industrial products. In the contemporary sense, consideration must also be given to the importance of the forest as a source of non-wood forest products and environmental services, as well as its role in the conservation of biological diversity and cultural values. Timber harvesting operations must therefore be planned in such a way as to accommodate, and where possible enhance these multifunctional characteristics of the forests. Timber harvesting in many Western European countries has changed from the use of chain saws (viz. motor-manual method) to a mechanised harvesting system known as Cut-To-Length (CTL). CTL harvesting involves two sequential operations, carried out by a “harvester” and a “forwarder”. The harvester is a large self-propelled machine (weighing 12 to 25 t) that fells the tree, de-limbs it, and cuts it into pre-determined lengths for subsequent collection by the forwarder. The forwarder moves along trails through the forest to collect the logs left by the harvester. The forwarder has its own loading crane and typically holds a payload of 5 to 12 tonnes (gross vehicle weight ca. 25 t). Felling operations can be classified into two main types namely “clear felling” or “thinning”. Clear felling usually involves the felling of a complete section of a mature forest in one operation. In contrast, thinning operations are carried out once or twice over a rotation of the forest, hence the so-called “first” or “second” thinnings. Thinnings are designed to remove some of the trees in order to enable the remainder to thrive, which is an essential silvicultural operation. During first thinning operations, it is necessary to open up access routes (trails) within the forest for use by harvesting and extraction machines. As the trails are the only routes for the machines to operate, they can become badly damaged due to repeated trafficking. The “trails” layout typically consists of short (ca. 200 m long in Ireland and UK) “side trails” (along which the timber is gathered) leading into “main trails” which act as the principal routes out to the stacking point. As the main trails are the most highly trafficked, most damage (e.g. deep rutting in excess of 0.3 m in some cases, soil compaction and tree root damage) may occur along these routes. The main traffic source through the forest is the forwarders, as they have to make repeated journeys to and fro in order to collect the logs. In contrast, the harvester fells the trees as it progresses slowly along the trails and generally has no requirement for repeated trafficking of the trails. In a clear felling operation, machinery movement is less restricted, hence, forwarders can reduce the number of passes along the same routes in order to minimise rutting and soil damage. Soil damage can also be minimised by effective use of brash i.e. stem and branches with diameter below the minimum set for utilisation. Depending on the soil types some soil structural change is an inevitable consequence of mechanised timber harvesting operations. Such damage is of particular importance if it impacts negatively on the environment (e.g. acceleration of reduced infiltration and surface water run off into watercourses). Mechanised timber harvesting operation should be planned and executed in such a manner as to avoid such potential environmental impact. Some sites are more “sensitive” to environmental damage than others. For example, wet peat soils on sloping ground can pose considerable difficulties for environmentally efficient harvesting operations. The environmental impacts of mechanised harvesting operations depend on several factors such as site type, matching the machinery to the site, machinery operation, layout of the trails so as to minimise trafficking by the forwarders. The time of year during which the operations are carried out may also be important. For example, harvesting on certain peat soils may be feasible only during the summer when the soil is relatively dry or during the winter in cold climates (such as Finland) when the surface soil is frozen. A key factor in determining the environmental impact of mechanised timber harvesting is the potential risk of run off water entering local streams, rivers or lakes. For example, traffic damage in trails (such as severe rutting) only poses a significant environmental risk if it channels surface run off water into a watercourse. Some rutting or soil scuffing is inevitable when dealing with mechanised harvesting operations on sensitive sites, but judicious selection and operation of the machinery system can minimise the potential site damage. However, given that this risk exists, the overriding principle must be one of containment of water flows so as to minimise the risk of run off into watercourses. While it is important that damage along the trails is minimised, this must be combined with planning the rack layout to include riparian buffer zones, which minimise the risk of direct run off into watercourses.
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Rehabilitation operations after the harvesting and extraction that includes levelling of deep ruts and establishing surface vegetation may be necessary also. Soil erosion can pose significant environmental risk when mechanised timber harvesting is carried out on sloping sites, particularly in dry climates (e.g. Mediterranean countries). Severe scuffing exacerbates the effect, hence the selection and operation of the mechanisation system is important in containing the risk. Scuffing has the effect of loosening the surface layer, hence predisposes it to erosion from wind or rain (these Mediterranean areas are prone to short periods of very heavy rainfall which can erode substantial volumes of soil, rapidly).
1.1 Definition of sensitive sites The sensitivity of a forest site encompasses a broad range of issues such as aesthetics and social functions, inherent archaeological features, economics, and potential environmental degradation such as the pollution of watercourses. The focus of this Operations Protocol (OP) is on how to minimise the impact that mechanised harvesting operations can have on the environment. With this consideration, the following definition of a sensitive site has been adopted (Nugent et al, 2003)1:
“A sensitive forest site is where alterations to normal mechanised harvesting practices are required in order to avoid adverse effects on the ecological, economic and social functions of the forest”
In this context, the sites at risk of degradation as a result of timber harvesting and extraction include: areas with gley soils, particularly on sloping terrain, and where there is insufficient brash to minimise surface disturbance; poorly drained shallow peat soils (less than 1 m deep) often with inferior tree crop with limited amounts of brash; deeper peat (greater that 1 m), usually with good drainage networks which present very difficult harvesting conditions; low organic matter soils on steep slopes in areas prone to drought and sudden spells of high rainfall (as occur in Mediterranean areas). The percentage of total forested area in Europe that is classified as sensitive ranges from 5% to 25%, depending on country (see Addendum I).
1.2 Machinery for mechanised timber harvesting As outlined earlier, mechanised CTL timber harvesting involves two separate operations, cutting the trees and transporting the timber out of the forest (viz. forwarding). There is a considerable range of timber harvesters and forwarders on the market (Appendix 1) varying in mass from approximately 10 to 40 tonnes. While most of these machines are fitted with large rubber tyres (ranging from 400 to 800 mm in width), “band tracks” which can be wrapped around the tyres to augment flotation are also available. The number of axles on these machines varies from 2 to 4, with bogie axles fitted in most cases. Typically, wheeled harvesters impose lower nominal ground pressures than loaded wheeled forwarders, and the use of band tracks can reduce the nominal ground pressure considerably (see Figures 18 & 19, also Appendix 2). Ground skidding comprises a significant proportion of harvesting operations in southern European countries such as Spain. Eco-efficient and cost-effective timber harvesting systems for sensitive sites should: (1) minimise or eliminate the associated soil disturbance (viz. terrain surface rutting, soil compaction,
layer inversion, erosion) that ordinarily may be incurred by harvesting and extraction operations; (2) minimise the damage to residual tree crop and seedlings, in thinning operations and natural
regenerating stands, respectively; (3) minimise or eliminate the damage to natural watercourses, and artificial drainage and soil
protection structures within or adjacent to the harvested areas; (4) optimise the productivity of the extraction operation, i.e. deliver the trees/logs to landings at
economic rates and with minimal loss of volume and/or quality, and;
1 Nugent, C., C.l. Kanali, P.M.O. Owende, M. Nieuwenhuis and S. Ward, 2003. Characteristic site disturbance due to harvesting and extraction machinery traffic on sensitive forest sites with peat soils. Forest Ecology and Management -: In Press.
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(5) ensure the safety of the extraction crews and other personnel involved in the related harvesting
processes, by ensuring that only skilled operators are engaged for planning and execution of the harvesting and extraction works.
1.3 Classification of site damage There are five main categories of site damage and secondary environmental degradation that can occur due to the operation of timber harvesting machinery. These can be categorised as follows: 1. Rutting: Repeated passes of heavy machinery along the same route lead to the development of
ruts. Rutting is a phenomenon closely associated with soft soils, such as wet peats or gleys. On most of these soils the rutting effect is incremental with each machine pass, but is most pronounced in the first 1 to 2 passes. In extreme cases, such as where inappropriate machinery systems are used, the soil structure can become so damaged that it turns into a liquid slurry (so called “slurrying”). In this OP, 100 mm is considered the maximum allowable rut depth (see section 2.3).
2. Soil compaction: The development of ruts (as outlined above) is in effect an outward
manifestation of soil compaction. The soil beneath the ruts becomes compacted, with the zone of maximum compaction extending to a depth equal to approximately half the rut width (viz. the zone typically extends down to ca. 300 mm). This compaction will reduce the water infiltration capability of the soil hence making the rut an excellent channel for surface water flow. It is therefore very important that the network of ruts, resulting from forest machinery operations are remediated and do not channel water into watercourses.
3. Surface disturbance: Forestry machines rely on slip between the wheels (or tracks) and the soil in
order to generated the required drawbar pull. The magnitude of this slip depends on several factors such as soil condition, vehicle weight, tyre (or track) type, inflation pressure, drawbar pull requirement and several other soil and vehicle parameters. Damage due to slip includes smearing of the soil surface, mixing (and dislodgment) of components of the upper soil layer (top 50 mm or so), root damage (see item 4, below) and, in extreme cases, a breakdown in the structure of the top layer of soil leading to “slurrying” in wet soils (see item 1, above). Loosening of the soil surface can lead to significant erosion problems in dry climates, such as in certain Mediterranean sites after rainfall.
4. Residual stand damage: Traffic induced stand damage can be important in thinning operations.
The process of soil compaction, outlined above, leads to compaction of roots, particularly those in the maximum compaction zone (viz. down to ca. 300 mm). Such compaction when associated with rutting may make the trees beside the tracks more prone to tipping over in heavy winds (viz. “wind-blow”). In addition, roots may become exposed as a result of a tearing action by the wheels (or tracks), and this can reduce subsequent tree growth and allow entry of pathogenic fungi. The extent of such root damage depends on the degree of rutting and the severity of the machine’s action. The use of metal cleats (track shoes) to enhance machine flotation exacerbates the effect. As rut depths can extend to 500 mm on poorly maintained main extraction routes, this implies that root damage may not be confined to surface roots and can have a significant negative impact on the residual trees.
5. Soil erosion and accumulation of sediment in streams: Input of soil to the watercourses (increased
suspended solids and sedimentation on the stream bed) is potentially the most significant change in the environment surrounding the forests. Erosion can be particularly severe in hot dry climates with occasional short periods of very high rainfall. Harvesting can increase soil input to watercourses especially in mountainous areas by a variety of processes, including: • surface erosion from landings and skid trails; • slope failure caused by the removal of vegetation; • physical damage to the stream banks, such as slippage and bank collapse, and; • increased surface run off as a result of clear fell operations
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The environmental impact of the above processes will depend on the proximity of the harvest site to watercourses, the expanse of the disturbed areas, site-sensitivity, topography, weather conditions and the intensity of the harvesting operation.
1.4 Purpose and applications of this protocol Sensitive sites can be vulnerable to damage by timber harvesting and extraction machines. Levels of sensitivity may vary considerably depending on weather conditions and seasonal factors. There is considerable variation in site sensitivity across Europe, such sites include: • Steep escarpments in the northern and southern parts of Italy, and areas of Spain and Portugal; • Compacted and rough terrain that has been planted previously can be prone to erosion in dry
countries, such as Spain and Portugal. This is particularly important after clear-felling, when there is increased surface run off potential;
• Areas in sensitive water catchments; • Peat based soils in Ireland and Finland (both flat and hilly terrain). In harvest planning the role of sensitive sites is primarily connected with the environment where the forest operations are being executed. The planning must consider - in the first instance - the requirements set by practising forestry so that the ecological and environmental aspects (e.g. maintaining biological diversity) are fulfilled in an economically and socially acceptable manner. Behind all actions must be the so-called forest principles. These "non legally binding" principles are broad statements covering the sustainable management of all forests and recognising national sovereignty over forest resources as well as the right to develop those resources. These and other general principles to be considered in applying this protocol (viz. the OP) in harvest planning can be read in the FAO model code of forest harvesting practice (FAO, 1996). The protocol is aimed at the development of methods for eco-efficient wood harvesting on sensitive sites, by aiding important operational decisions e.g. how and where to drive machines through a stand; whether to use cable extraction or not. The primary aim is to integrate the operation of the various machines involved (e.g. harvesters and forwarders) so as to achieve cost effective and eco-efficient operations that: (i) minimise disturbance and potential damage to the residual stands and forest environments; (ii) optimise product quality i.e. ensures that the end-user obtains the type/quality of product required; (iii) maximise the socio-economic benefits; (iv) can assist work organisation and planning; (v) are ergonomically sound, and foster good work organisation; (vi) are cost effective; (vii) are sustainable, and can be applied to the range of sensitive sites across Europe. In the process of the development of this OP, a review of the existing knowledge base from literature has been conducted as well as primary experimental work and analyses of secondary data in the following key areas: • machine-soil interaction models for harvester and forwarder movement within the forest; • development of guidelines for harvester-forwarder versus cable systems selection and operation; • evaluation of the role of state-of-the-art on-board electronics, telemetrics and GIS systems for real-
time integration of key operational elements of the timber harvest chain (including data management and information flow that may be useful in optimisation processes);
• development of Geographical Information System (GIS) based routing optimisation model for in-forest movement of forwarders, and evaluation of extraction road networks in the context of cable extraction systems;
• evaluation of the socio-economic, ergonomic and environmental benefits / constraints associated with improvements in the efficiency of the wood harvesting chain;
A multidisciplinary approach and consultation was taken in the development of this protocol, encompassing, inter alia, terramechanics, telemetrics, computer based systems optimisation, environmental impact and socio-economic effects. A forest machinery manufacturer (Timberjack Oy, Finland), two universities (University of Helsinki, Finland and National University of Ireland, Dublin), a research institute (CNR, Italy) and two end-users (Coillte, Ireland; Servicios Forestales SL, Spain)
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were involved in the consortium. This OP supports best management practices and its potential uses are not confined to the partner organisations or countries. It is envisaged therefore, that it will contribute to the development of integrated and sustainable wood harvesting systems for sensitive sites that minimise environmental impacts and enhance the competitiveness of the European forestry industry. It will also foster the synergism between forestry and rural development.
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2 MATCHING MACHINES TO SITES
2.1 Introduction On sensitive sites harvest planning is primarily concerned with matching harvesting systems and equipment to the soil and terrain. The results generated by models using different terrain, soil and machine parameters can be used directly to make comparisons between machines operating under different conditions. This section provides some guidelines on how to achieve eco-efficient operations consistent with Sustainable Forest Management (SFM) for sensitive sites.
2.2 Terrain Classification In forest operations, terrain classification refers to the division of the terrain into units, which present the same or at least a similar degree of difficulty from the point view of the operations. Information on micro and macro-profiles of the forest terrain are therefore useful for the planning of extraction routes within the forest. The IUFRO-terrain classification system describes the salient factors that may affect forest operations. Other systems of terrain classification are also available, but for the purposes of this OP, Terrain Classification is intended to provide a distinction between primary classification (terrain description) and secondary classification (operational use of the primary indicators). Broadly speaking, for all the different terrain classification systems there are three principal parameters that are taken into account, namely ground condition, ground roughness and slope (see Tables 1 & 2).
2.2.1 Ground condition It is clear from Appendix 1 that machines for timber harvesting are heavy and they traverse sites that range in ground bearing capacity (GBC) from 100 kPa for “good” sites (e.g. dry mineral soils) to as low as 20 kPa for “poor” sites (e.g. wet blanket peat soils). The machines, depending on configuration, can impose nominal ground pressures ranging from a minimum of 30 kPa to as high as 100 kPa (Figures 18 & 19, Appendix 2). In operation, the ground contact pressure imposed by the machine should not exceed the GBC of each site (soil) type. This implies that the size of machine (particularly wheel or track size, total mass and configuration) must be selected to meet the GBC limits of the soil in the sites of operation, at the time of wood harvest. The time of harvest is a critical factor, as large temporal variations in ground bearing capacity can be expected, particularly in sensitive sites. For example, a peat soil may have a GBC of 80 kPa when dry in the summer period but this may fall to as low as 20 kPa under wet conditions. The ground pressure imposed by wheeled forwarders can be reduced to as low as ca. 35 kPa by fitting band tracks, thereby giving these machines mobility under soft soil conditions (L-GBC). Forwarders impose higher static ground pressures than harvesters, and where multiple transportation cycles are required, they are the main causative agents of soil and stand damage. The actual ground pressures imposed can be up to 2.5 times the static values, mainly due to ground contours and dynamic effects generated by terrain roughness. The movement of vehicles over the soil can cause soil damage in the form of scuffing, compaction and rutting. The extent of this damage depends principally on the traction characteristics of the machines, the ground contact pressure imposed on the soil and the number of machine passes. It is well documented that rutting damage on low GBC soils is gradually exacerbated with successive machine passes. Therefore, benefits can be gained from limiting the number of machine passes along the same route. While GBC is well established as an indicator of a soil’s trafficability, there is no consensual method of its assessment. Several methods of rating GBC are used, each with some limitations. In this Operations Protocol (OP), the soil is classified into one of three possible GBC groups, viz. L (Low GBC, assumed < 40 kPa), M (Medium GBC, assumed 40 – 80 kPa) or H (High GBC, assumed > 80 kPa). The parameters used in classifying the soils are Cone Index (CI), shear strength and deformation modulus (E value), as each of these can be measured quite readily in the field using portable equipment. The parameter values associated with each GBC group are given in Table 3.
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Table 1. General terrain classification scoring for Ireland (Adapted from Forest Service, 2000). Ground condition Ground roughness Slope
Good (1) : H-GBC Even (1) Gentle, < 8o or 14 % (1)
Average (2) : M-GBC Uneven (2) Intermediate, 8o – 14o or 14 - 25 % (2)
Poor (3) : L-GBC Rough (3) Steep, > 14o or > 25 % (3) Very poor (4) : very low GBC (not trafficable)
Table 2. Machinery operations most suited to respective terrain classes (Adapted from Forest Service, 2000).
1.1.1 2.1.1 3.1.1 4.1.1
Forwarder, Skidder, Horse Tracked Forwarder, Cable
1.1.2 2.1.2 3.1.2 4.1.2
Forwarder, Skidder, Horse Forwarder, Tracked Forwarder, Cable
1.1.3 2.1.3 3.1.3 4.1.3
Forwarder, Skidder, Horse Cable
1.2.1 2.2.1 3.2.1 4.2.1
Forwarder, Skidder, Horse Tracked Forwarder, Cable
1.2.2 2.2.2 3.2.2 4.2.2
Forwarder, Horse Forwarder, Tracked Forwarder Tracked Forwarder, Cable
1.2.3 2.2.3 3.2.3 4.2.3
Chained Forwarder, Cable Cable
1.3.1 2.3.1 3.3.1 4.3.1
Forwarder, Cable Tracked Forwarder, Cable
1.3.2 2.3.2 3.3.2 4.3.2
Forwarder, Cable Forwarder, Tracked Forwarder, Cable Cable
1.3.3 2.3.3 3.3.3 4.3.3
Cable
Example of application: Terrain class 1 . 2 . 3 in Table 2 denotes‘Good’ ground condition (1), ‘Uneven’ groundroughness (2), and ‘Steep’ slope (3).
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Table 3. Classification of the three GBC categories based on three soil parameters. GBC category Cone Index (kPa)* E Shear strength (kPa) L-GBC < 300 < 20 < 20 M-GBC 300 – 500 20 - 60 20 - 60 H-GBC > 500 > 60 > 60 Low, Medium or High GBC, abbreviated respectively as: L-GBC, M-GBC or H-GBC. The soil is classified into a GBC category based on the “least common denominator” – viz. the parameter value that falls into the lowest GBC category. *maximum value in the top 300 mm of the soil profile
2.2.2 Ground roughness There are several classification systems for ground roughness, which are fundamentally similar. The NSR ground roughness classification is widely used in forest operations, and this compares with the ground roughness categories used in Table 1, as follows. Table 4. The Nordic Council on Forest Operations Research (NSR) ground roughness classification system, compared to the ground roughness categories used in Table 1. NSR Roughness
Roughness Category
Obstacle Allowed Obstacle height, cm
Class (cf. Table 1) height, mm cases 20 40 60 80 Average distance between obstacles, m
1 Even (1) H(200) a) b)
1.6- 5.0 5.0-16.0
>16.0
>16.0
>16.0
2 Even (1) H(200-400) a) b)
<1.6 1.6-5.0
>16.0 5.0-16.0
>16.0 >16.0
>16.0 >16.0
3 Uneven (2) H(400-600) a) b)
<1.6 <1.6
1.6-5.0 1.6-5.0
5.0-16.0 1.6-5.0
>16.0 >16.0
4 Uneven (2) H(400-800) a) b)
<1.6 1.6-5.0
<1.6 1.6-5.0
5.0-16 1.5-5.0
5.0-16.0 5.0-16.0
5 Rough (3) H(400-800) a) : i)
<1.6 <1.6
<1.6 <1.6
1.6-5.0 <1.6
5.0-16.0 <1.6
Site roughness imposes limitations on the range of machines that may be used in eco-efficient operations. For example, for a NSR Roughness Class of 4 (i.e. uneven as per Table 1), a vehicle with a high ground clearance (> 600 mm) and bogie axles is recommended, as this configuration enhances the ability of the machine to traverse the associated obstacles.
2.2.3 Slope The gradient can be obtained from contour maps at the macro level, and GIS techniques can be used for operations and route planning. In addition, information on gradients, together with ground roughness and condition, can be used for the selection of appropriate mechanisation systems (e.g. cable v. ground based systems). The choice of cable systems for operations on steep ground is influenced by each of the terrain classification factors outlined above. These are summarised in Tables 1 & 2. Cable systems are the only feasible option on L-GBC soils on steep slopes. Details of the requirements for cable systems are given in chapter 4.
2.3 Soil-machine interaction
2.3.1 Nominal Ground Pressure (NGP) There are several soil-machine interaction models developed in the literature, each with its own specific assumptions. One of the main criteria in machine site matching is the wheel/soil contact pressure. It is a simplification of the vertical stress the loaded pneumatic tyre or track imposes on the soil, and several methods have been proposed for its estimation. A widely used ground pressure indicator is Nominal Ground Pressure (NGP), which is given as:
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For wheeled machines:
brWNGP⋅
=
Where:
NGP = Nominal Ground Pressure, kPa W = wheel load, kN r = wheel radius, m b = tyre width, m
For tracked machines:
( )L1.25bWNGP +=
Where:
W = track load, kN L = length between the wheel centres, m b = track width, m Examples of typical NGP ranges that may be encountered in common forest operations are given in Table 5. Table 5. Outline of range of NGP values (Olsen and Wästerlund, 1989)
NGP kPa
Reference value
17 A person with boots, standing on two feet 35 A person with boots, standing on one foot 35 to 50 12 t forwarder with 5 t load
2.3.2 Soil Rutting In order to minimise the level of surface rutting, the NGP should be matched to the Ground Bearing Capacity (GBC). Rutting can interfere with tree growth and may also accelerate surface water run off and therefore carry the forest soils into streams. The Finnish Forestry Development Center at Tapio (Finland) defines ruts of economic and ecological consequences to be those exceeding 100 mm depth and extending for at least 0.5 m. Overall, rutting is only considered to be a problem where it is greater than 100 mm deep for more than 10 % of the total trail. This implies that it may be acceptable to operate on sites where ruts are occasionally deeper than 100 mm, but where such occurrences are infrequent. Dynamic effects due to ground undulations can cause significant deviations from the nominal ground pressure. The addition of “balanced” or “power down” bogies on machines helps to counteract the imbalances in the applied ground pressure due to tractive effort.
Cone Index/NGP ratio The ratio of Cone Index (CI) to NGP may be used to define operational limits and ranges for forest harvesting machines. While other modelling approaches have been developed in the literature, this system offers a practical approach that enables the soil conditions to be taken into account (e.g. softness, winter v. summer operations) and the machine ground pressure matched to these conditions. Figure 1 indicates that the operational limit lies in the CI/NGP range of 3 to 7. As outlined previously, 100 mm rut depth is considered to be the threshold for ruts of economic and ecological consequence, and this is achieved at a CI/NGP of 5 (see Figure 1). It is therefore proposed to use a CI/NGP value of 5 as the criterion for establishing the required NGP for a given vehicle operating on sensitive sites. For example, typical soft peat soils have a CI in the region of 200 kPa, hence the NGP for the machine should be ca. 40 kPa.
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Figure 1. Rut depth (m) versus CI/NGP ratio (Wronsky & Humphreys, 1994; Anttila, 1998).
Tyre footprint area The tyre footprint area is difficult to determine precisely because it depends on tyre stiffness and soil deformation characteristics. For a pneumatic tyre the footprint area depends on tyre deflection, which is influenced by the inflation pressure and wheel load, but it also depends on the deformation characteristics of the soil (Figure 2).
Figure 2. Tyre footprint on different soil moisture regimes (Hallonborg 1996). There is a certain critical inflation pressure, above which the tyre behaves like a rigid wheel, but at low pressures the deflection governs the footprint area formation. Under constant inflation pressure the footprint area depends on soil bearing capacity. There are different methods to measure the footprint area, which give somewhat different results. Therefore tyre footprint area (contact area) should be considered as a guideline value only.
0,00
0,05
0,10
0,15
0,20
0,25
0,30
10 20 30 40 50 CI/NGP
RU
T D
EPTH
, m
TECHNICAL MOBILITY* ECONOMIC MOBILITY**
ENVIRONMENTAL LIMIT***
* this is the limit of mobility ** this CI/NGP value of 5 gives a nominal rut depth of 100 mm *** the CI/NGP ration below which rutting develops
Rut threshold (viz. 100 mm)
Technical Mobility *
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Modelling of multi-pass rut depth The development of wheel ruts due to multi-pass wheel traffic is depicted in Figure 3. In the initial pass, the wheel compresses the soil and creates the first rut, z1. The following wheel travelling along the same line moves over the compressed soil, whose bearing capacity is higher, and the subsequent rutting, measured from the previous rut bottom, is smaller. However, in cases where the surface layer of the soil is strong (e.g. due to a surface root mat or frozen top layer) and overlies a low bearing capacity soil, there may be very little sinkage for the first few passes. Once the surface layer is broken, sinkage increases considerably. None of the available tyre ground pressure models are perfectly suitable for assessing the suitability of tyres for sensitive sites. It is recommended, however, to adopt models which include tyre deflection because it leads to more environmentally acceptable selections. The WES-method (which is cone penetrometer based) is a frame of reference for this OP, and is considered appropriate for assessing the suitability of forwarders and harvesters for use on sensitive sites.
2.3.3 Damage to roots Root damage refers to the injury or severance of the root system of a living tree due to mechanical forces or reduction of root growth due to less favourable soil conditions resulting from compaction. The Forestry Development Center Tapio (Finland) defines root damage as the damage below the root collar, and within a 1 m circle from the centre-line of the tree. Root damage that occurs further than approximately 1 m is considered insignificant economically. Deformation of roots if less than 20 mm diameter causes only slight discolouring of the trunk wood, hence damage to roots of less than 20 mm in diameter is not considered in this protocol. Root damage in rutting is caused mainly by shear forces which can break the root, or peel it thus exposing the tree to fungal attack. Cutting off a part of the root system may reduce the growth rate of the tree, but generally decay due to the attack of fungi is considered as the main economically important consequence. It has been established for tree seedlings that root growth decreases with increasing soil density. However, in mature forests where compaction occurs on a relatively small proportion of the root mass, only minor effects on root growth are expected. Researchers at the Technical University of Munich, Germany, (Matthies, 2002) examined root damage caused by forest machinery and developed a five point classification system with increasing severity from 1 (superficial) to 5 (severe). These classes are indicated in Table 6 and also illustrated in Figures 5 and 6. They found that wheeled machines tend to cause less severe damage than tracks (typically 70 % of the damage caused by wheeled machines is in Class 1 or 2 while 70 % of the damage caused by tracked machines is in Classes 3 – 5). This distribution is more or less independent of ground slope or other factors. As a result they recommend that tracked harvesters should be used only for sites where wheeled machines have problems with mobility.
z2
z3z4
z1
Figure 3. Model of wheel multi-pass rut depth where zi is the wheel sinkage and z1 to z4 signify
the wheel passes.
Figure 4. Illustration of damage inflicted by machine traffic on an exposed root.
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Table 6. Damage classes as defined by Matthies (2002) Damage Class Damage description
1 Surface disturbance 2 Superficial peeling but no damage in the body of the root 3 Surface and sub-surface damage, including some cracks and splintering 4 Surface and sub-surface damage, including cracks and splintering 5 Severe damage – broken main roots
Figure 5. Damage Class 1: surface damage to the root, no internal damage (typical of wheeled machines).
Figure 6. Damage Class 5: severe damage – roots are split (typical of tracked machines with “aggressive” grousers)
The selection of appropriate machinery for operation on sensitive sites is a complex matter, depending on a range of interacting variables (e.g. weather, soil type, terrain roughness, etc.). From the point of view of implementing this OP, it is desirable that the selection process is simplified in so far as possible, hence the CI/NGP selection criterion is used, as outlined previously.
2.3.4 Soil Erosion The choice of machine and in particular the traction devices (e.g. tyres v. tracks) influences the risk of soil damage that may lead to subsequent erosion. In general, soil erosion risks are a function of: • slope length and severity (erosion is proportional to approximately the second power of the slope, %); • the sensitivity of the soil to erosion, which generally depends on the fine particle content of the soil; • the proportion of bare soil surface; • the severity, extent and duration of rainfall events.
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This means that erosion risk is high under mountainous conditions, with heavy rainfall, and on fine grained soils if large patches of vegetation are destroyed. Environmental risk analysis and recommendations for soil recovery operations after logging must therefore be included in the harvest work plan. Therefore harvesting on these classes of sensitive sites should include erosion prevention measures with contingency plans for soil recovery operations. The sedimentation and run off from roads may cause a reduction in water quality, visual impacts, slope stability on unstable sites, and the loss of productive forest area. Such adverse effects may be minimised by: (a) location of roads on ridges or elevated contours and away from watercourses where possible; (b) installation of adequately sized culverts and flumes to control run off; (c) allowing for road consolidation before use; (d) maintenance of road surfaces, drainage structures, cut-offs and culvert installations.
2.3.5 Example of machinery system selection The classification of the site on the basis of the three parameters outlined in Table 1 (viz. ground condition (score 1 to 4), roughness (score 1 – 3) and slope (score 1 – 3)) enables the appropriate mechanisation system to be selected from Table 2. For example, a soft peat soil (L-GBC with a score of 3) with an even surface (score 1) and on flat ground (score 1) can be harvested by a conventional forwarder/harvester system, provided the NGP of the machines is low (< 40 kPa). In contrast, the same soil type on a steep slope can only be harvested by a cable system. In all cases, the combination of rough surface and steep slope dictates that cable systems must be used, regardless of soil bearing capacity.
2.4 Consequences of mismatching machines to harvest sites
2.4.1 Soil compaction and rutting Excessive soil compaction arises where the machinery is not properly matched to the site (see previous sections). The consequences of excessive soil compaction are: (1) it decreases the pore space and interferes with water and nutrient movement in the soil; (2) it reduces surface water infiltration, hence, enhances conditions for surface run off and soil erosion to occur; (3) the reduced porosity and drainage decreases the supply of air to the tree roots; (4) it can adversely affect the mechanical stability of the tree root system (increasing the risk of “wind-blow”). The following techniques may be used to minimise the extent of soil compaction and rutting (see examples in
Figures 7 - 9): (1) limiting the number of machine passes along the extraction routes; (2) reduction in payload; (3) the use of alternative routes to avoid wet areas; (4) the use of high flotation tyres, band tracks (Figure 8) or low ground pressure tracked machines; (5) the use of brash mat (Figure 7).
Figure 7. 15 tonne harvester fitted with dual tyres and band tracks (NGP ca. 35 kPa) on low GBC soil under wet conditions cause very little soil disturbance where brash mat is available.
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Figure 8. 15 tonne forwarder with front dual wheels and rear bogie axle fitted with wide band-tracks (NGP ca. 33 kPa unladen; 56 kPa with 10 t load)
(a) (b)
(c) (d)
Figure 9. Traffic damage to soft soils (i.e. Low GBC soils) (a) despite the availability of sufficient brash, rutting can eventually become a problem on the main extraction
routes, as the brash becomes degraded by the excessive traffic. In this case, considerable rutting occurred after 50 passes of a 10.5 t tracked forwarder (NGP < 30 kPa unladen; 40 kPa with 8 t load) along the main extraction trail even though sufficient brash was available (as evidenced by broken stems);
(b) rutting after 10 passes of a wheeled forwarder (NGP ca. 70 kPa with 8 t load) along a main extraction trail comprising a shallow L-GBC gley soil (0.4 m) overlying solid foundation;
(c) channelling of surface water along rutted trails presents a significant risk of run off into local waterways; (d) ponding, which confines the water to a given area, presents no significant run off risk. However, it
interrupts the normal water flow and consequently the drainage patterns on a harvesting site. This can lead to zones that are too soft for machines to traverse.
Injudicious selection and operation of machinery systems can cause quite severe soil damage, leading to increased risk of run off into waterways (Figure 9). The aim of a harvest plan is to control and monitor the harvest operation in order to ensure that the standard of work is of a high quality and also to reduce the risk of damage to the site and residual stand. However, practical difficulties may arise beyond the scope of the harvest
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plan. Figure 10 shows how even if a machine is correctly selected to suit the site, heavy rainfall prior to harvesting operations can alter the situation. However, it is important that machine width is taken into account when selecting high flotation systems, as excessively wide machines may be difficult to manoeuvre within the forest, particularly during thinning operations (Figure 11).
Figure 10. Damage to soil even after the harvest plan has matched machine to site, due to exceptionally wet summer weather and scarcity of brash mat at this particular location.
Figure 11. 10.5 tonne forwarder fitted with dual tyres and band tracks enables low nominal ground pressures (<30 kPa with an 8 t load) to be achieved. However its excess width may cause damage to the residual stand, as seen in the photograph on the left where considerable bark damage has occurred.
2.4.2 Machine immobilisation Under very soft conditions (e.g. ground bearing capacity < 40 kPa) it is particularly important that machines with low nominal ground pressures are used (e.g. tracked machines or machines fitted with 8 wheels, flotation tyres and band tracks). Failure to do so can result in machines becoming bogged down, and in severe cases extremely difficult to harvest and extract (Figures 12 and 13). While brash mat will help counteract sinkage, it cannot compensate fully on very soft soil (Figure 12).
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Figure 12. Even with the use of brash mat, soil water presents the most significant constraint to machine flotation and mobility. In this case, a light weight (10.8 t) 4-wheeled harvester (NGP ≅ 60 kPa) was incapable of operating on a low GBC soil.
Figure 13. Forwarder (600 mm wide tyres, 8 t load, NGP ca 70 kPa) operating on a waterlogged site (L-GBC) with a shallow (<700 mm depth) solid foundation. The machine caused severe rutting as it sank right down to the underlying solid stratum – see also Figure 9(b).
2.5 Cost considerations Work-study allows for objective and systematic examination of all factors which govern operational efficiency in order to effect improvement. With respect to forest machines, work-study may lead to improvements in forest harvesting procedures and planning for the necessary access locations during establishment of forest stands. For example, for the key machine time elements of wood harvesting systems, the typical functional processing times may be generated to evaluate machine productivity as illustrated in Figure 14 (Spinelli et al, 20022). Based on realistic cost factors, the associated harvesting costs may be derived (see Figure 15, Spinelli et al, 20022 &3).
2 Spinelli, R., P.M.O. Owende and S.M. Ward. 2002. Productivity and cost of CTL harvesting-debarking of fast-growing Eucalyptus globulus stands using excavator based harvesters. Forest Products Journal 52(1): 67-77. 3 Spinelli, R., B. Hartsough, P. M. O. Owende and S.M. Ward. 2002. Mechanised full-tree harvesting of fast growing Eucalyptus Sp. stands. International Journal of Forest Engineering 13(2): 49 – 60.
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(a)Harvest of 2 m logs
0
5
10
15
20
25
30
35
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
Tree volume (m3)
Mac
hine
pro
duct
ivity
(m3 /P
MH
)
F1 F2 F3 F4 F5
(b) Harvest of 4 m logs
0
5
10
15
20
25
30
35
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
Tree volume (m3)
Mac
hine
pro
duct
ivity
(m3 /P
MH
)
Figure 14. Timber harvester productivity as a function of tree size and form (F1 to F5) for two log size categories.
(a) Harvest of 2 m logs
0
2
4
6
8
10
12
14
16
18
20
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
Tree volume (m3)
Har
vest
ing
cost
($/m
3 )
F1 F2 F3 F4 F5
(b) Harvest of 4 m logs
02468
101214161820
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
Tree volume (m3)
Har
vest
ing
cost
($/m
3 )
Figure 15. Timber harvesting cost as a function of tree size and form. Further details (including software) on cost assessments of harvesting systems are available on the ECOWOOD website: www.ucd.ie/~foresteng
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A burned, eroded stand
An eroded re-afforested landscape
A grazed eroded landscape
Creep stabilisation
Erosion can be a major problem in dry climates. This can be exacerbated by forest fires and short periods of torrential rainfall. The above are some examples of landscapes and practices in Mediterranean countries
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3. MACHINE TELEMETRICS
3.1 Rationale for integrated logistics in procurement of wood Mechanised wood harvesting and transport operations are multi-function systems, with a range of complex interactions and inter-dependencies. The overall efficiency of the operations can be optimised by integrating the elements in the production chain, thereby leading to more efficient production, better quality and competitively priced products. For example, forests are often located in remote areas with products destined for multiple locations, hence harvesting and transportation operations would benefit considerably from integrated logistics. Logistics in the wood harvesting chain (source of wood, eco-efficient harvesting and extraction, costing of process operations, wood quality grading and degradation during storage, transportation requirements and infrastructure, and the potentially dynamic product markets) are complex in the sense that wood procurement, active deliveries and production plans are interrelated, as shown in Figure 17. The system is further complicated by variable wood assortments (ca. 20 in Finland, 5 in Ireland and Spain, and 3 to 6 in Italy) that must be related to different processing techniques and markets, the varied range of wood procurement companies with independent harvesting schedules and wood consignments, and the industry's partial reliance on favourable weather factors. Telemetrics can enhance efficient tracking of the different wood assortments, and the optimisation of the wood harvesting operations, especially cut-to-length harvesting.
Figure 17. Components of integrated wood harvesting, extraction and transport.
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3.2 Mechanisation systems for wood harvesting Modern wood harvesting mechanisation systems are referred to as Cut-to-Length (CTL) systems, and comprise two primary machines, a harvester and forwarder. The harvester fells, de-limbs and cuts the trees into specified lengths (hence Cut-to-Length); while the forwarder collects the logs and transports them to a collection point, for road transport by truck. On-board electronics and telemetric data transfer can control the harvester’s CTL function so that the machine produces the optimum assortment of log sizes to match the market (viz. end-user) requirements and maximise the profitability of the enterprise. In addition, the use of telemetric systems (using satellite based GPS, GIS navigation, and load cells) to track forwarder movement within the forest can help to minimise soil damage and ensure that environmentally sensitive areas are not traversed. This technology can also be used to monitor log deliveries to and from the collection points, thereby improving transport scheduling, and inventory control and traceability. European Union (EU) countries can be classified into three groups, based on the level of wood harvesting mechanisation and the application of telemetric systems, as follows: • High degree of wood harvesting mechanisation, with well developed telemetry use level: Finland; • High degree of wood harvesting mechanisation, with relatively low telemetry use level: Ireland, Denmark,
Sweden, United Kingdom, Germany, Netherlands, Austria, and France, and; • Low degree of wood harvesting mechanisation, with low telemetry use level: Italy, Spain, Portugal, Belgium
and Greece.
3.3 Requirements for telemetric data transfer Modern on-board data capture and transfer systems require an effective mobile phone network to be in place if remote data transfer capability is to be effected. GSM phone systems are available in all EU countries, but coverage in forest areas is incomplete in all countries (and quite poor in many), except Finland and Denmark. This implies that periodic transmission (e.g. where the operator periodically downloads data via a phone line or transfer in PC diskettes) is the only effective data transfer method in many situations. While such periodic transmissions may fail to capitalise on the full potential of a truly real-time integrated system, daily communication is adequate in most situations and is a significant improvement on the current regimes. Satellite based GPS, and GIS maps are required for the monitoring and routing of machines in the wood harvesting chain. GPS signals can be problematic from time to time, but they can be supplemented by dead-reckoning systems, which are adequate for most applications.
State-of-the-art in integrated telemetrics Several information software systems are available which can enable the following tasks to be carried out: • Prepare cutting instructions (in the office) – log size and quality so as to optimise product value and transfer
of related instructions via the GSM phone network (real-time) or daily download (batch); • Prepare detailed GIS maps of the forest and the road network between the forest and the end-users; • Modify the cutting instructions using stem profile data collected via machine telemetric systems from the
harvester - the harvester has a real-time tree diameter and length measuring system. While this procedure could be carried out in real-time where GSM coverage is available, it is usually sufficient to alter the cutting instruction data on a daily basis, hence batch data transmission is usually adequate for this application;
• Maintain an up to date inventory of timber production (either real-time or batch).
On-board electronics All modern harvesters come with on-board data capture and monitoring systems including stem diameter, log length and data logging (usually PC based, which also give the operator a range of options for value optimisation). These are usually standard items but the peripheral systems required for data transfer (e.g. GSM transmission system, satellite navigation and GIS maps) cost extra. However, many operators and managers are unfamiliar with the full capabilities of current on-board electronic systems, and fail to use most of the systems’ potential. In contrast to harvesters, a variable number of forwarders have GPS and GIS hardware, or on-board telemetrics. In the best cases route optimisation systems, based on GPS and GIS, are available and are in use for wood haulage trucks.
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GIS and GPS play a central role in the planning and management of wood harvesting operations. Current technology enables the machine (harvester, forwarder or truck) to have a GIS map on-board and to receive information via telemetric data transfer (e.g. using mobile phone transmissions). Such GIS maps can be updated or overlaid with new information as it arises. In some cases telemetric transfer may not be feasible (e.g. due to poor mobile phone coverage in the area) and hence daily updates may be required (e.g. through land-line phone transmissions or on CD). These data updates can be passed from one machine to another (in real time if telemetric links are available), thus aiding the overall efficiency of operations. Vehicle movements can be tracked and controlled by combining GPS positioning data with map data. For example, the “base map” of the harvest site on the harvester’s computer can be updated with information on “no-go” zones such as heritage areas, soft zones or riparian buffer zones. The operator may be able to use GPS position sensing to avoid such areas. Other site features such as winter harvest zones can be identified as can the location of landing areas. GIS can play a central role in the planning of within-forest routes in order to ensure that soil and stand damage is minimised. Route optimisation models are available to assist in this process. Ground truth data will need to be collected prior to completion of the harvest plan, in order to verify conditions on the site. In addition, maps can be updated telemetrically during harvesting operations as new features are identified (e.g. areas of butt rot in Spruce, exceptionally soft zones, etc); and this information enables subsequent operations to take account of these new features. Map detail is important, and clarity of presentation is essential. Maps need to give sufficient details to enable the operator to carryout his tasks efficiently yet not overburden with too much detail. The use of warning symbols helps improve clarity.
This GIS map shows a stream (left picture) and its buffer zone (right picture)
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Cost of telemetric systems Estimates indicate that a fully integrated telemetric system (for the complete wood harvesting chain) would incur an expenditure of €25,000 to €45,000, depending on the make and model of system used. However, some elements of these costs may be spread over a number of machines. The associated variable costs could range from 0.01 to 0.1 €/m3 of harvested wood, depending on the frequency of data transfer, i.e., whether batch or real-time transmission is adopted. While no cost-benefit analysis of their impact on system efficiency has been carried out in the literature, it is expected that the cost benefits would far outweigh the operating costs. In addition, the system offers considerable collateral benefits to the environment.
3.4 Operational benefits The key operational benefits of the use of data capture and telemetric systems include: • Effective scheduling, control and monitoring of operations; • Improved productivity, reduced labour inputs and increased machine availability; • On-line data such as parts and service manuals; • Machine fault diagnosis and service scheduling; • Machine tracking for operation management and safety; • Reduced fuel consumption, machine maintenance and down-time; • Timely delivery of quality logs to the end-users, and; • Timely updating of databases in the logistics of wood supply.
3.5 Environmental benefits The environmental benefits of the use of data capture and telemetric systems are quite significant. These include: • The use of on-board GIS maps and satellite navigation to monitor the movements of machines in the forest.
This assists in certifying that the operations have been carried out in an environmentally compatible manner. For example, the machines can be kept away from “no-go” zones such a riparian strips and archaeological sites. In addition, the number of passes can be limited to avoid excessive rutting on soft soils, surface scuffing in high erosion risk areas, or tree root damage;
• The efficient use of machines reduces their energy consumption; • The optimum bucking (viz. cross cutting) of the logs ensures reduced wood wastage, thereby extracting
maximum product use from the forest, and; • Truck route optimisation to minimise road damage, consistent with economic efficiency.
3.6 Recommendations The use of data capture and telemetric systems offers considerable environmental and economic benefits in the future development of wood harvesting mechanisation within the EU. This OP advocates the use of such telemetric and data capture systems on sensitive sites both for day-to-day operations and production certification. The technology exists (albeit with certain deficiencies such as lack of consistent mobile phone coverage and satellite signal) but needs to be promoted on a pan-EU basis. Investment in hardware, GIS data quality, improved mobile phone coverage and data transmission speeds are key elements in achieving this goal. In particular, a partnership approach is needed with the telephone service providers in order to address the latter two issues. Education and training are essential in order to enable the industry to utilise the full potential of the technology. This requires considerable investment in training modules, operator certification schemes, and the use of virtual reality simulators as training and systems optimisation aids. A more detailed discussion of telemetrics in wood harvesting is given in Kanali et al (2001)4.
4Kanali, C. L., P. M. O. Owende, J. Lyons and S. M. Ward. 2001. Assessment of on-board Electronics, Operator Assist and Telemetric Controls, and Logistical Systems within the Wood harvesting Chain. Project Deliverable D1 (Work Package No. 2) of the Development of Protocol for Eco-efficient Wood Harvesting on Sensitive Sites (ECOWOOD). EU 5th Framework Project (Quality of Life and Management of Living Resources) Contract No. QLK5-1999-00991 (1999-2002). 92 pp
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4 RECOMMENDED PRACTICE The practices presented in this OP have two main components, (a) those applicable to all sites (viz. general conditions); and (b) those additional constraints that are site specific. The user must consider both components in the application of the protocol to a given site.
4.1 General recommendations The following recommendations apply to all sites (but the user must add to these the site-specific components, presented later): 1. Every effort must be made to minimise the risk of damage to the stand and site. It is essential that
the risk of groundwater and watercourses pollution, and soil erosion, arising from mechanised harvesting operations are minimised;
2. Wheeled machines (viz. those fitted with tyres as distinct from band tracks or fully tracked machines) are the most suitable for eco-efficient harvesting on sensitive sites;
3. Machines and tyres should be selected to suit the site and soil type (see specific site details, later); 4. Riparian buffer zones should be included in order to minimise the risk of run off into watercourses; 5. Machines should avoid travelling closer than 50 m to a watercourse without adequate protective
measures in place.
4.2 Site specific recommendations There is considerable variation in the types of sensitive sites throughout Europe. These range from wet peat soils in Ireland (where run off into local watercourses is a major concern) to steep dry escarpments in Mediterranean countries (where erosion is difficult to contain). Site slope is of particular importance in regard to run off and erosion risk, and the mechanisation system needs to be matched to the site, and the option of using cable extraction systems must be considered. Peat soils are common in Ireland, Britain and parts of Fennoscandia. There are two main categories of these soils: 1. Raised bogs and fen peats (typical GBC range: 30 – 80 kPa) which are common in the Irish
midlands, Finland and parts of Scotland. These are generally on flat ground and the peat can be several metres deep.
2. Blanket peats (typical GBC range: 10 – 60 kPa) which occur in highland terrain in Ireland and Scotland. These are generally on sloping ground (or on flat areas of highland from which water drains to lower reaches) and have lower ground bearing capacity (GBC) than raised bogs. Peat depth can vary from 0.5 to 2 m with an impervious layer beneath the peat. These particular sites are very prone to rutting and severe soil structure breakdown (viz. slurrying).
Similar principles would apply to wet clay soils which have low ground bearing capacities. In the case of soils at risk from erosion, particular attention must be paid to the avoidance of surface scuffing. The use of tracked vehicles is not recommended as the cleats can cause considerable soil scuffing. In addition, brash mat should be used in particularly difficult situations.
4.3 Machinery Selection
4.3.1 Site factors The incorrect choice of machine or perseverance with unsuitable existing machines may lead to severe ground damage. Harvesting and extraction machines should also be compatible with respect to environmental impact and productivity. Contractual timber harvesting is often based on compromise machines (i.e. may not be optimal for a specific site) since they carry out harvesting work on different types of sites. Contracts for the harvesting of sensitive sites should therefore stipulate preferred machine types, i.e. ensuring that only contractors with site-suitable machines are allowed on sensitive sites.
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4.3.2 Machine types Figures 18 and 19 show the common configurations of harvesters and forwarders that are used in CTL wood harvesting systems (see also Appendix 1). The nominal ground pressures (NGP) for typical configurations are indicated, with further details provided in Appendix 2.
(a) 2 axle harvester, tyre widths range from 500 – 800 mm (see Appendix 1)
(b) 3 axle harvester, tyre widths range from 500 – 800 mm (see Appendix 1)
(c) 4 axle harvester, typical tyre width = 600 mm (see Appendix 1)
(d) Tracked harvester
* NGP is highly dependent on tyre size and general vehicle configuration (see Appendix 2)
Figure 18. Common axle configurations (2,3 and 4 axles) for harvesters and the associated nominal
ground pressures (NGP).
Typical NGP > 80 kPa *
Typical NGP range 50 – 70 kPa *
Typical NGP range 45 – 60 kPa *
Typical NGP < 30 kPa *
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* NGP is highly dependent on tyre size and general vehicle configuration (see Appendix 2) Figure 19. Common axle configurations (viz. 2, 3 and 4 axles) of forwarders and associated nominal ground pressures (NGP), when fully laden. Inset shows the fitting of band-tracks to increase traction and reduce the NGP, hence minimising the risk of rutting and soil damage on sensitive sites. The GBC of raised and fen peat soils varies from a high of ca. 80 kPa when dry (or frozen as in Finnish winters) to a low of ca. 30 kPa when wet (as during Irish winters); while blanket peats can have a GBC as low as 10 kPa (no harvester or forwarder on the market can achieve such a low ground pressure, in practice). Therefore, considerable restrictions on mechanised harvesting operations are necessary, particularly for blanket peats, during periods when their GBC values are low. This means paying particular attention to the time of harvest (avoid periods when the soil is soft), the choice of machine (particularly its weight), tyre selection and the layout of the traffic routes (trails) within the forest.
Typical NGP 80 – 100 kPa *
Typical NGP 50- 60 kPa *
Typical NGP 50 – 60 kPa *
Typical NGP 70- 80 kPa *
Typical NGP 40 – 50 kPa
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Tyres Wheeled machines (viz. those fitted with tyres as distinct from those fitted with band tracks or fully tracked vehicles) are the preferred option for both harvesters and forwarders as they offer the best compromise between manoeuvrability and soil/stand damage. Judicious selection of the machine and tyre size can enable forwarders to operate at ground pressures as low as 40 kPa (see Appendix 2). Tyre width can be a limiting factor in thinning operations, with 800 mm wide being the maximum feasible. This implies that on the wetter sites (L-GBC), particularly wet blanket peat sites, such machines have the potential to cause considerable soil damage. As the use of band tracks or fully tracked vehicles is not recommended on bare soils (see below), this implies that peat sites should not be harvested when they are particularly soft. This means restricting such sites to relatively dry harvesting periods, or winter harvesting in Fennoscandia (when the soil is partially frozen). The machinery should be fitted with as wide a set of tyres as possible. The fitting of 700 mm wide tyres is recommended for raised or fen peatlands, while 1 m wide tyres (viz. dual tyres) may be used for blanket peatlands, where overall machine width is not a problem (e.g. clear felling). The use of such tyres will help ensure that it generally takes several passes of a fully laden forwarder (or harvester) to achieve soil rutting greater than 100 mm, on an un-brashed surface. Band Tracks While band tracks offer excellent flotation characteristics for poor sites (and may be the only option available), they: 1. may cause considerable surface scuffing which leads to increased run off risk and higher levels of
root damage; 2. may tend to break down the brash mat layer by incorporating it into the soil surface, thereby
negating its beneficial vehicle supporting effects; 3. may produce deeper ruts at corners due to their partial scuffing or skidding action; 4. may transport soil out of the forest on to the landing used for piling the timber pending collection
by trucks. This makes it difficult to maintain a clean roadway and landing area; 5. make short distance road transfer more difficult (track removal or low-loader required). Full (metal) Tracks (Bulldozer type) Full (metal) tracked machines offer the best flotation for such soft conditions, but are not recommended for the following reasons: 1. they have poor manoeuvrability compared to wheeled vehicles; 2. low ground clearance; 3. they cause considerable scuffing of the soil surface (particularly at corners) and damage to shallow
roots; 4. they have higher repair costs and down-time than wheeled vehicles; 5. they also transport considerable volumes of soil out of the forest on to the landing area, similar to
band tracks; 6. they are ergonomically poor. Band tracks which are suitable for traction on slopes have a different cleat design than those used for flotation.
4.3.3 Effective Use of Brash The cutting of timber involves de-limbing the trees, and the branches that are removed can be placed on the forest floor to act as a type of mat over which the machines can move (viz. “brash mat”). These brash mats are quite strong, although their strength varies considerably between species and branch size. Nevertheless, brash mats offer considerable support for the machines and can be very effective at reducing soil damage. The quantity of brash available varies with tree species, site and harvesting operation. For example, there is usually plenty of brash available during first thinning, but it may be scarce during subsequent thinning operations (as less trees are taken out and the trees tend towards more crown than branch growth). In contrast, clear felling operations usually have plenty of brash available (as the trees are mature and all are being felled). This scarcity of brash during the second and subsequent thinning operations, and in some species, may necessitate that, on sensitive sites, such operations should be carried out only during periods when the soil bearing capacity is relatively high
34
(viz. during drier summer months in mild climates and winter months in cold climates, when the soil may be partially frozen). In Finland and Sweden, all the brash may not be available for brash mats as the brash may be collected from the cutting area for energy use.
Figure 20. After 28 passes on heavy brash mat (picture on right) there is no sign of soil disturbance while after 4 passes with no brash mat (picture on left) the soil surface is exposed. Machine traffic routing within the forest 1. In a normal thinning operation the feeder trails have an adequate covering of brash mat. Brash
may not be essential since such feeder trails only require very few passes of a fully laden forwarder or harvester, thereby limiting rutting potential. However, in cases where the feeder trails are long (> 200 m), additional forwarder passes will be required, hence the use of brash mat is essential, particularly at the exit end of the trail. In addition, a good cover of brash mat is also essential at the junctions where the feeder trails meet the main exit (extraction) trails, as considerable rutting can occur here due to machine manoeuvring while turning.
2. It is desirable that the main extraction trails have a full covering of brash mat and that this is
maintained after repeated traffic. Brash mat has a variable life depending on its thickness and quality, hence it may need constant repair/replacement when used along the main extraction trails which can have 50 or more passes. However, this may not be possible in practice due to insufficient supply of brash, in which case the layout of the main trails must be such that drainage and run off water is prevented from entering watercourses. This involves establishing a detailed water flow profile for the site and the imposition of dams, silt traps and riparian buffer zones.
3. In a clear-fell operation, normal mechanised harvesting patterns ensure that brash tracks are laid
down and that traffic is confined to such tracks. This will help to ensure that rut depth does not exceed 100 mm which is the maximum desirable for the minimisation of run off.
4. Landings, where the forwarders unload (viz. headlands), are particularly prone to severe damage
(due to repeated traffic and manoeuvring), and are often adjacent to an open drainage ditch. In this situation it is very difficult to avoid some run off occurring into the drain. Therefore, this must be dealt with in either of two ways:
(a) The rutting minimisation and brashing procedures outlined above, must be implemented. If drains need to be crossed, a temporary crossing should be put in place (see later).
(b) If the above (item a) cannot be guaranteed, such sites should not be harvested until the GBC is in the M-GBC category. This restricts them to summer sites in mild climates and/or winter sites in cold climates where soil freezing occurs.
It is recognised that even with the best planning and upkeep, main extraction routes eventually degenerate through wear and tear. Some damage is also inevitable when the extraction is over long distances, and is more serious where brash supply is exhausted and a limited choice of routes exist. In such situations, ruts will form, which may lead to ponding in low lying areas. However, in a typical
35
harvesting operation only a small proportion of the ground (< 10 %) is covered by extraction trails and routes, hence, such damage may be remedied after the operation. Supervision of operations should recognise developing problems and be able to implement effective counter-measures. There is limited flexibility in the choice of machine when contractors are engaged for harvesting operations. Therefore, damage levels on some sensitive sites may be high due to poor planning, layout and choice of machine by the contractor. For example, intermittent working may degrade the brash before the extraction is complete, and poor route choice and maintenance may result in a site having to be completed by cable systems. The use of partial loads and double handling on particularly soft soil conditions may be an option; but this can increase the overall cost of forwarding by up to 30 %. In order to avoid the outlined risks of site damage, it is recommended that: (1) potential long distance forwarding operations should be reduced by optimisation of extraction route
networks; (2) extra brash should be laid over suspected weak areas; (3) adequate track reinforcement (with brash or other retrievable material), stream crossings, and
embankment rolling should be provided in time and before the start of harvesting operations; (4) sensitive sites that require the laying of brash should be completed when the brash is still fresh and
effective in the control of traffic induced site damage; (5) plan operations to avoid acute corners.
4.4 Management Considerations
4.4.1 Management of watercourse crossings and site drainage structures The impact of harvesting operations on aquatic resources may be minimised by pre-harvesting planning. It is important that the inputs of soil and other suspended solids (e.g. wood debris) and sedimentation resulting from harvesting operations are minimised since they can have a long-term effect on aquatic biota and their surrounds. Harvesting plans for sensitive sites must include details of soil and sediment management regimes. Salient techniques for minimising soil and sediment movement towards watercourses are: (1) Machinery roads/tracks should be away from streams to prevent the direct discharge of surface run
off to the streams. Management of machinery traffic for operation on slopes should be such as to prevent surface run off directly down the slope;
(2) Long ground extraction routes on steep slopes (> 15o) should be avoided, especially if the cutting and extraction operations are done under wet weather conditions, and where there is potential risk of land slides;
(3) Stream banks and stream bed should be protected at machinery crossing points, in order to prevent excessive machinery slippage and bank collapses;
(4) Riparian buffer zones should be included in the planning of harvesting operations in areas adjacent to river and stream beds, and drainage channels from such areas should not discharge directly into the surrounding streams;
(5) On sensitive sites, cable extraction rather than forwarding should be considered, in order to minimise soil disturbance;
(5) If the harvesting and extraction schedules are such that they must be done under wet weather conditions, operating procedures should be modified to minimise soil loss and sedimentation. Practical options include: (a) the construction of adequate silt-traps and filtration of run off through vegetation before discharge into watercourses; (b) provision and maintenance of adequate brash mat (Figure20), and / or temporary traffic corridors (Figure 21).
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Figure 21. Possible mechanical strengthening of ground with wooden platforms (left) and discarded tyre mats (right) to minimise rutting. The economic feasibility is a function of distance to be strengthened and volume of wood to be transported (Lassila, 20025.).
4.4.2 Forest road maintenance Forest roads are a significant cause of soil erosion and associated sedimentation as they expose bare soil, change slope profiles, concentrate flows and can disturb riparian buffer zones. Therefore road maintenance is important in keeping road design features operating properly to avoid excess erosion or concentration of flow. Control and mitigation measures for road maintenance include: (1) Traffic restrictions on certain roads to prevent road deterioration, erosion and sedimentation. Wet
weather traffic may be restricted to prevent rutting. In cold climates, certain roads may be restricted to times when soils are frozen.
(2) Harvesting equipment can be equipped with lowered pressure tyres and central tyre inflation to reduce ground pressure on forest roads/routes, thereby reducing rutting, sediment yield and road maintenance.
(3) Regular inspections of roads, especially during and following high rainfall, snow melt or spring thaw (particularly on steep slopes prone to landslides). Inspection is a key element of road maintenance and represents a step towards operational adaptive management. Some actions that might result from inspection include: grade or resurface road, repair or unclog culverts, reconstruct road dips and water bars that were flattened during harvesting operations.
4.4.3 Landing Area Landing areas are where logs are delivered during the extraction process, piled and stored temporarily for secondary transport to the processing facilities. As the interface between extraction and transport operations, landing areas and their surroundings are exposed to potential hazards such as excessive soil puddling and deep rutting (Figure 22) due to multiple machine passes. There are also potential hazards from fuel spills and oil contamination, since they are also used as service and repair areas for harvesting machines and equipment. On sensitive sites, the scarcity of firm soil foundation also increases the possibility of sedimentation or pollution of surrounding streams or groundwater. Surfacing with crushed stone or gravel may be required to develop adequate performance, that will allow for extraction and transportation of timber (Figure 22). These areas are frequently associated with roadside drains and these drains will also need to be protected.
5 Lassila, K. 2002. Ajouran mekaaninen vahvistaminen puunkorjuussa maaperävaurioiden vähentämiseksi (Mechanical strengthening of ground to decrease rut-formation in forwarding). Thesis (in Finnish) for M.Sc.(For.), Department of Forest Resource Management, University of Helsinki. 68 p. + 2 app.
37
On sensitive sites it is recommended that: (1) landing areas should be selected in order to avoid any interference with the movement of other
normal traffic on the roadways. Repeated forwarder traffic should be kept off all roadways and landing areas in order to maintain these in a suitable condition for normal vehicular traffic i.e. forwarders should remain off-road when depositing timber on the landing areas. The increased intensity of off-road forwarder movement close to the landing area may require extra preparatory work or remedial work through the use of a brash mat (see damage, Figure 22b). This may necessitate brash having to be transported from further afield in the forest. Studies have shown that where an adequate brash mat is available, 50 or more passes of a loaded forwarder on soils with a GBC as low as 30 kPa are possible without causing excessive soil damage.
(2) measures should be taken to avoid spillage of fuel and lubricants. Refuelling should be restricted to specific areas (not having tanks precariously perched on stacks of timber). The use of bunded tanks is recommended to prevent pollutants from entering streams or ground water. In case of spillage accidents, the procedure outlined in Figure 23 should be followed.
(3) landing areas should be rehabilitated after use. Debris should be removed. Any damage to drains should be repaired or blockages removed. Where the landing areas are not to be used again, further operations may include levelling of the deep ruts, and the establishment of vegetation in order to return the site to its original state.
(4) landing areas should be kept litter free at all times.
(a) (b)
(c) (d) Figure 22. Illustration of damage and counter measures associated with landing areas on sensitive sites showing: (a) deep rutting and puddling along the main trail leading up to the landing; (b) waterlogging (left foreground) in the unpaved area adjacent to the landing area; (c) & (d) surface stabilisation with gravel to allow efficient stacking and transportation of logs.
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4.4.4 Environmental Pollution The risk of significant oil or chemical spillages may be higher at landings than elsewhere. Landings are the temporary timber storage areas for secondary transportation and they also act as the end-points for the transportation cycles of both extraction machines and timber haulage trucks. They are also used for the delivery and storage of fuels, machine oils, chemicals and spare parts; and hence may be vulnerable to spills of oils and chemicals. A set procedure for dealing with potential incidents of pollution may therefore be considered as an important component of eco-efficient wood harvesting on sensitive sites. Figure 23 suggests a generalised procedure that may be used to contain possible pollution incidences. Forest Chemical Management The environmental impact of forest chemicals can be minimised by the selection of the least-impact chemicals and the application of minimum amounts at the appropriate times. Spray drift should be minimised by the imposition of weather restrictions on spraying (e.g. no spraying when there are high wind velocity, temperatures and relative humidity), the use of shotgun or stem inject chemical and the maintenance of a vegetative riparian buffer zone. Only trained operators should be employed for any such operations.
Life Cycle Analysis (LCA) Mechanised wood harvesting systems utilise fossil fuels and consume mineral oil lubricants, each of which has a significant contribution to green house gases. Environmental concerns and general public awareness currently impose a requirement to minimise the emission of such gases, hence, it is desirable that wood harvesting machinery should have low fuel and oil consumption in relation to their productivity. They should also have low oil leakage and be suitable for the use of environmentally friendly (biodegradable) oils and lubricants. Life cycle analysis (LCA) is a technique for assessing the potential environmental conservation associated with a production system, by compiling an inventory (energy audit) of relevant inputs and outputs. LCA evaluates the potential environmental impacts associated with those inputs and outputs and interprets the results of the inventory and impact phases in relation to set objectives. With respect to wood harvesting, such an energy audit should be aimed at identifying the elements of the overall energy demands that impact most on the environment, and to formulate an Energy Reduction Strategy (ERS) for possible reduction in energy consumption with minimal influence on machine productivity. For CTL wood harvesting systems the recommended ERS comprises a suite of measures, including: the reduction of fuel and lubrication hose breakages through improved guarding; increased use of biodegradable vegetable oils; and use of ultra-low chainsaw oil drip-feed system (Klvac et al, 2003)6. Dealing with spillages Most minor oil or chemical spillages can be dealt with by means of a pollution control kit (Figure 23 a & b). This comprises a small (< 10 m long) portable floating boom and absorbent pads that can be placed across a stream to stop the surface flow of the pollutant slick; and the absorption pads are placed on the upstream side of the boom to absorb the slick. Such kits are available commercially and are contained in a small sack suitable for carriage on the machine. It is recommended practice that all machines carry such a pollution control kit. In contrast, major pollution incidents require a concerted action that may involve local authorities such as emergency services, environment agencies, etc. The procedure for dealing with such situations is depicted in Figure 23 c.
6 Klvac, R., S. Ward, P.M.O. Owende and J. Lyons. 2003. Energy Audit of Wood Harvesting Systems. Scandinavian Journal of Forest Research, 18. In Press.
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Figure 23 (a) This portable pollution control kit is suitable for use on small spillages. A kit should be
carried on all machines.
Figure 23 (b): Example of the deployment of the pollution control kit depicted in Figure 23 a. The surface oil slick (visible on the right of the picture) is absorbed by floating absorption pads (light blue). The inflatable boom (white) prevents the absorption pads from moving down stream.
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Figure 23 (c). Model for handling of harvesting related pollution incidences.
Are emergency services required?
1. OVERALL ASSESSMENT
Is it safe to enter spill area?
2. ASSESS POLLUTION INCIDENT
Carry out First Aid if Required
3. STOP FURTHER SPILLAGE
Can watercourses be protected with resources on site?
4. CONTAIN SPILLAGE
Site manager assumes control of incident.
Has spill been contained?
Who needs to know?
5. SUMMON ASSISTANCE e.g. forestry board or environmental agency
Will incident have environmental repercussions?
6. INFORM OTHERS
Return Site to original State
7. CLEAN UP
8. PREPARE INCIDENT REPORT
Yes
No
Yes No
Yes No
Yes No
Summon Relevant Emergency Services
Keep Clear of Spill Area (Personal Safety is a Priority)
Use resources to Divert & Contain Pollutant
Assess Resources Required
Inform Relevant Authorities
Yes No Si
te M
anag
er to
Org
anis
e Re
sour
ces R
equi
red
to
Con
tain
Spi
ll
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4.4.5 Operations monitoring It is important that all harvest sites are monitored and that harvesting operations are carried out in accordance with Best Management Practices, and the principles and criteria of SFM and legislation relevant to each country. A harvest site should be monitored at regular intervals during and also on completion of harvest operation to ensure compliance with the harvesting plan. Such inspections should be documented, and any violations promptly reported and rectified. The harvest site monitoring form is essential to minimise environmental degradation arising from harvesting operations. It will ensure that adverse effects identified on a site can be minimised. Where a thinning operation has occurred the site should be monitored to ensure the thinning plan was followed and minimal site damage was achieved. A thinning control assessment should be made frequently, at predetermined and agreed intervals. The following table is an example of some of the information that should be included in a harvest site monitoring form.
Table 7. Example of Irish Harvest Site Monitoring Form. Site Quality Inventory
Rating * Recommended Action
Access/Exit points adhered Adherence to felling pattern Agreed rack layout Agreed refuelling/servicing areas adhered to Amenity/Recreational/Archaeological sites protected Control of litter Damage control on forest roads Drains slash free Fences protected Full recovery of produce Harvest Site Plan on site Hazards/Safety plan Log Quality Control in operation Maximisation of product segregation Roads (vehicular) Roadside stacking Slope stability Soil Disturbance Stem damage control Stump height Stump treatment Thinning control Warning signs erected Water courses protected Water Quality *S = satisfactory; U = unsatisfactory One of the objectives of eco-efficient harvesting is to ensure that operations are conducted without significant pollution of waterways. A pollution incident report should therefore be an integral part of on-site pollution control (Table 8).
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Table 8. Illustration of a pollution incident report form. Pollution Incident Report Form Pollution incident reporting should be part of the overall safety procedures or ‘Work Safe’ protocols in timber harvesting
Forest:…………………………………………… Location:………………………………………….
Incident Summary: ……………………………………………………………………………………….. …………………………………………………………………………………………………………….. …………………………………………………………………………………………………………….. …………………………………………………………………………………………………………….. ……………………………………………………………………………………………………………..
Report initiated by:……………. Date:…………………………… Time:…………………………..
Local assistance summoned:………………………………………………………………………………
Emergency services summoned:………………………………………………………………………….
List of persons involved or notified of incident: ………………………………………………………… ……………………………………………………………………………………………………………. ……………………………………………………………………………………………………………. ……………………………………………………………………………………………………………. ……………………………………………………………………………………………………………. State any further follow up that may be necessary: ……………………………………………………… ……………………………………………………………………………………………………………. ……………………………………………………………………………………………………………. State the necessary recommendation following incident:………………………………………………… ……………………………………………………………………………………………………………. …………………………………………………………………………………………………………….
Signed:…………………………………………… Date:……………………………………………...
This form should be forwarded to the relevant Operational Managers
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4.5 Selection and operation of cable systems on sensitive sites Harvesting of sensitive forest sites presents considerable limitations to the use of ground-based forest harvesting machines as significant damage to forest ecosystems may be incurred. In some cases, cable systems may be the only alternative. Cable extraction or cable logging systems involve the transportation of material within the forest by means of steel cables, the load being partially or wholly lifted off the ground. It is different from the ground-based wood extraction systems (forwarders and skidders) in that soil-machine interaction is minimal or eliminated altogether, hence, it offers possible means of minimising the site disturbance and damage that may result from wood harvesting and extraction. For example, soil losses of between 0.16–0.51 m3 per m3 of extracted timber have been recorded for skidding operations with a crawler-tractor under the unfavourable condition of low soil bearing capacity7. In contrast, the expected soil erosion resulting from the use of cable system and by skidding with horses are both less that 0.14 m3 per m3 of extracted timber. Although wood extraction with cable systems is environmentally friendly, hence may contribute to Sustainable Forest Management (SFM) on sensitive sites, it is also recognised that it is more complex and expensive than current alternative option such as ground skidding. Generally, there has been a decline in the use of cable systems in Europe due mainly to the cheaper cost (less that 50% of the production costs for cable extraction), and increased capability of harvester and forwarder combinations to operate on steep terrain. Currently, less than 3% of the annual timber harvested in the European Union (EU) countries is by cable systems. The relatively lower productivity of cable systems (1−10 m3 per Productive Machine Hour), when compared to ground-based systems (5−25 m3 per Productive Machine Hour) significantly reduces profit margins. In addition, the high manual workload and skill demands for operating the systems, and comparatively low wages, impede the recruitment and retention of personnel. While wood extraction with cable systems may be more complex and expensive than ground-based systems, it is a viable complement to the adaptation of ground-based machines for SFM on sensitive sites. New trends in wood harvesting with cable systems are therefore geared to the development of: integrated machine processes (to maximise on productive time) and enhancement of mobility of harvesters used with cable extraction systems on difficult terrain (bearing capacity < 40 kPa, and gradient > 20% or 12o); improvement of related operational planning/logistics, and; ergonomic consideration (viz. minimisation of workload, and improvement of tools and accessories), in order to enhance the cost-effectiveness. Advances in these areas, and the need for eco-efficient wood harvesting and extraction suggest that cable systems will continue to play a significant role in Sustainable Forest Management on sensitive forest sites. Tables 1 & 2 can be used to determine if a cable system is appropriate for a given site.
Motorised yarding Motorised yarding involves the use of a motorised carriage, cable lines and cable towers to extract timber. A radio controlled petrol engine moves the carriage. Motorised carriages are a new innovation that eliminates the need for a haul back line (Figure 24), which reduces the set-up times significantly. The need for winch drums for the cables is replaced with a motorised carriage. A small winch is required to tension the main cable. Figure 24. Woodliner™ motorised carriage and setup (Konrad Forsttechnik, 2001). 7 Tiernan et al (2002) [page 54]
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The motorised carriages can extract both uphill and downhill, but the carriage is more suited to downhill extraction as a very large engine is required to haul loads uphill. Motorised carriages weigh approximately 300 kg and load capacities are approximately 1.5 to 2.5 tonnes. The main advantage of this system is the reduced set-up times as it uses only one cable, and the reduction in the number of personnel required to operate the system. Timber can be extracted in cut lengths or whole trees. Recent developments have seen the introduction of cable systems that combine cable yarders and processing vehicles (Figure 25). Figure 25. Details of a combined yarder/processor (Konrad Forsttechnik, 2001). Use of steep terrain harvesters and excavator based cable units The use of ground-based harvesters was traditionally not possible on steep terrain with slopes over 35%. Up to recently these areas were seen as the sole preserve of chainsaw harvesting because other harvesting machinery such as skidders and purpose-built harvesters and forwarders could not operate safely on these steep slopes. However, developments in the late 1990’s have seen the production of steep terrain harvesters that are capable of operating safely on slopes between 35–55% (Figure 26). This new development is a more productive (particularly when processing larger diameter trees), cost-effective and safer means of felling timber on steep terrain, when compared to motor manual harvesting (Figure 27), and is becoming popular in countries where there is a shortage of forest workers.
The following parts are radio controlled: + Swing cylinder + Winch for help rope + Tension drums + Timber landing plate + Stabilisers
Options: • Processor head • Grabsaw • Grab Penz
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Figure 26. Examples of steep terrain harvesters
0
20
40
60
80
100
0 10 20 30 40 50 60DBH (cm)
Prod
uctiv
ity m
3 /PM
H
Steep terrain harvesterChainsaw
Figure 27. Variation of productivity with Dbh for mechanised and conventional
(chainsaw) harvesting on steep slopes (after Oswald and Fruti, 2001). The combination of steep terrain harvesters with cable crane extraction has resulted in large increases in productivity. The productivity of the steep terrain harvester is 12 to 15 times higher than the productivity of chainsaws and this difference increases with increasing tree size dimensions (Figure 27). The innovations in tiltable cabins on tracked chassis and concept walking harvester (Figure 28) will enhance the eco-efficient operation of ground-based machines for operations on sensitive sites with soft soils.
46
Figure 28. Valmet™ steep terrain harvester and Timberjack walking harvester (concept machine). Excavator Based Cable Systems Excavator based cable yarders are considered to be cost-effective alternatives to the conventional (purpose-built) yarders. These excavator based cable units are converted into cable systems by adding winches to the excavator and modifying the boom to act as a tower (Figure 29). This option is proving to be more cost-effective than purchasing a purpose-built cable system, mainly because it utilises existing excavator base machines that were redundant (fully or almost fully depreciated). The main advantages of excavator based cable yarders are:
• fast set-up times (no requirement for tower anchors); • multipurpose machine; • ease of operation, and; • good off road ability.
The necessary modifications depend on whether the highlead or skyline rope configuration is to be used. The modifications may include: • Guarding the undercarriage; • Installation of Falling Object Protective Structures (FOPS), i.e., guard on front window; operator
protection frame, and; steel mesh on operator protection frame guarding the front window; • Work lights; • Detachable skyline tower on dipper (secondary boom); • Winch mounting chassis; • Double drum winch; • Two 200 mm pulleys (attached to tower); • Strawline drum; • Hydraulic motors and control system; • Automatic release choking system.
The required modifications for a skyline are similar to the highlead, but also include a skyline drum and a locking skyline carriage.
47
Figure 29. End and side views of an excavator based cable extraction system in working position.
Operation of cable system With the use of cable extraction systems on sensitive forest sites, it is recommended that: (1) the capacity of the yarders and cable cranes selected should be commensurate with the size of
material to be handled (trees or logs), and the limitations imposed by the nature of the terrain of operation, bearing in mind there can also be some limited site and stand damage (Figure 30)
Figure 30. Situations that may cause shock loading of a cable system (Visser, 1999).
(2) skyline systems are preferred over highlead systems as they ensure adequate suspension of the
loads above the ground to minimise site disturbance or eliminate it altogether, and they also allow for longer extraction distance in multi-span systems;
(3) proper planning, adequate crew training, and operation control should be implemented.
48
(4) well rooted and stable support and anchor trees must be carefully selected, hence, on low gradient
soft soil sites with shallow root-plating (e.g. peat based soils of western Europe), heavy mobile plant such as tracked excavators may be used as anchors instead of trees. Intermediate supports should be used at regular intervals.
(5) where practicable, the road networks should be located along ridges, and as far away as possible
from stream networks.
4.6 Socio-economic considerations The increased reliance on technology in harvesting operations has resulted in major social and economic changes for the individual worker and the rural economy. Some of the salient socio-economic impacts are economically quantifiable factors such as employment levels, productivity and income as well as factors that are not easily measured but nevertheless important such as quality of employment and health and safety issues.
Employment Levels One of the major direct effects of the mechanisation of harvesting operations has been the dramatic decline in the number of forest workers directly employed by the forest owner and industry. Contract labour now accounts for a large and growing share of the harvesting workforce. Statistics on the numbers employed in harvesting operations are often difficult to obtain and can be unreliable as a high share of self-employed, farmers and seasonal or part-time workers do not get recorded. However, in Finland official figures have shown a 76 % reduction in the numbers employed in felling since 1970. In Ireland and Spain, no official figures are published on the numbers employed in wood harvesting. Nevertheless, the reduction in employment can be estimated using productivity and harvest volume figures. Therefore, at the current level of mechanisation in Ireland, there was an estimated 94 % reduction in employment for each m3 harvested. While mechanisation has reduced the numbers directly employed, studies have shown that indirect employment in auxiliary industries has increased.
Productivity A direct productivity comparison between operators or countries is not possible because of differences in stand characteristics. Nevertheless, considerable differences in productivity may be observed. For example, in Ireland a harvester operator can be more than ten times as productive as a chainsaw operator. Developments in harvesting operations in Finland between the 1970 and the 2000 resulted in a productivity increase from 1,264 m3/worker-year to 11,429 m3/worker-year. Technological advancements have enabled the harvesting industry to expand production while lowering unit costs per m3 thereby improving its competitive position in the global market. Training and work experience are also paramount in optimising production. Income For the majority of workers employed in wood harvesting, mechanisation has improved their standard of living. In harvesting the most common method of payment is based on productivity. Hence, as productivity has increased due to mechanisation so has the income of operators. However, despite the increased income, many operators were still earning below the average industrial wage of their respective countries. Operators often tried to compensate for the low wage level by working over the legal maximum working week. Therefore, it was not surprising that a recent study showed that a substantial proportion of operators considered their wage level to be poor.
Quality of Employment Working conditions in harvesting operations have improved due to mechanisation (Figure 31). It has eliminated most of the heavy physical labour associated with harvesting: much of the work is now physically light, sedentary work that is however mentally demanding. Mechanisation has exposed machine operators to multi-stress situations. Operators are responsible for the selection of trees, protection of the remaining trees and the environment, as well as the maintenance of expensive machines. In Spain and Italy, the inherent differences in the physical working environment means that
49
some harvesting machines do not properly suit the terrain - this may increase operators’ mental workload. Training and work experience are shown to reduce the mental workload associated with operating increasingly sophisticated harvesting machinery. Mechanisation has increased the working year for the majority of the workforce. Nevertheless, the increased responsibility and independence experienced by machine operators has resulted in greater work satisfaction.
Figure 31. Forest machinery operators’ opinions regarding working condition, expressed as % of respondents (O’Sullivan, 2002)8
Training Technological advancement and changing production requirements have made considerable demands on everyone involved in harvesting operations. These demands can only be meet after systematic preparation for their tasks during training. Manufacturers of harvesting machinery offer short training courses to operators, teaching them how to operate and maintain their machine. However, the growing complexity of equipment and harvesting standards means that basic training is no longer sufficient. Specialised training is required for operators of forwarders, harvesters and cable cranes, but because of the high costs involved operators working for contractors or on their own account often remain insufficiently trained. Therefore, the high level of training reported from Ireland and Finland is a positive indication that forestry contractors are prepared to participate in organised training courses or they were already forest machine school graduates and were aware of the long-term benefits of such investments. European Social Fund (ESF) support has been very beneficial in this respect in Ireland. Lack of appropriate training creates a shortage of skilled operators and this reduces production levels and increases pressure on the operator, as well as compromising worker safety.
Healthy and Safety Concerns Mechanisation has changed the health and safety concerns affecting forest workers. Improved ergonomics and training together with mechanisation have significantly reduced acute accident rates. However, while acute accident rates have reduced, mechanisation has brought new previously unconsidered risks such as whole body vibration (WBV), repetitive strain injury (RSI) and problems related to mental isolation. WBV can cause pain and discomfort by affecting the back, shoulders, neck and arms and in some cases the internal organs of the operator. The repetitive nature of using the machine controls is likely to cause RSI and this problem will be exacerbated by WBV. Despite
8 O’Sullivan, G. (2002). The Socio-Economic Impacts of Increasing Levels of Mechanisation in Harvesting Operations in Ireland, Finland and Spain. Master of Agric. Science (Forestry) Thesis. National University of Ireland, Dublin. 150 p.
* No operators surveyed in Finland were currently working as chainsaw operators
0%
20%
40%
60%
80%
100%
Chainsaw Operators
Machine Operators
Chainsaw Operators*
Machine Operators
Chainsaw Operators
Machine Operators
Ireland Finland Spain
Good Average Poor
50
substantial ergonomic improvement since the advent of mechanisation the number of operators suffering from RSI and WBV has only reduced slightly. Machine operators often work on their own, following non-standard hours and in areas that are often not easily accessible, hence the need for safety systems is significant.
Considerable advances have been made in the past few decades in developing and introducing highly mechanised and specialised wood harvesting machinery. Increased levels of mechanisation in harvesting have altered former socio-economic patterns and have been central to economic expansion and improvement in the quality of life for forest workers. The major conclusions emerging regarding the socio-economic impact of mechanised harvesting systems are that such systems result in: • a reduction in the numbers directly employed in harvesting operations; • increased productivity; • increased income for operators; • a reduction in the heavy physical workload associated with harvesting; • increased mental workload; • improved working conditions; • a reduction in the risk of acute injury; • new health risks such as WBV and RSI. Due cognisance should be taken of these factors when introducing mechanised systems, particularly in countries where manual methods are still in common use.
51
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APPENDIX 1: SPECIFICATIONS FOR SOME COMMERCIALLY AVAILABLE FOREST HARVESTERS AND FORWARDERS Specifications for harvesters
AVAILABLE CRANES Dimensions mm TYre options
Torque kNm MACHINE
Max. felling diameter mm
Ratio max. felling diameter/weight
Number of wheels
Weight kg
Length Width 500 600 700 800
Turning radius m
Engine output kW
Hydraulic system Transmission Autobalancing
system reach m lifting turning
Measuring system Optimal tree-size l
Optimal work Further information
Caterpillar 550 550 0.042 4 13000 6650 2780 122 180 Thinning/clearcut
Caterpillar 570 550 0.037 15000 6790 2780 165 180/ 220 Clearcut/thinning
Caterpillar 580 550 0.031 6 17500 7300 2990 165
Power-controlled/load-sensing
Hydrostatic Yes 10,1
220
Motomit 4/ Cat <2700
Clearcut/thinning
Farmi Trac 775 450 0.046 9850 7050 2200 4,6 75
Relieved constant pressure/load-sensing
Hydrostatic-mechanical No 7-8,7 75 22 Several alternatives 200/300 Thinning
Tracked, not manufactured any more
Logman 801 550 0.050 4 10000-10900 5750 2700 5,5 100
129 Relieved constant pressure
Hydrostatic-mechanical 9,4 140 35 Several alternatives 300/500 Thinning/clearcut
Logset 6H 550 0.035 6 15500 7100 2880 Front and rear
129 Motomit 4, Motomit IT, Dasa 4 Late
thinning/clearcut
Logset 8H 600 0.034 6 17500 7260 2940 Front and rear
168
Load-sensing Hydrostatic-mechanical Yes 8.3/10 168/188
Motomit 4, Motomit IT, Dasa 4 Clearcut
Logset 506H 650 0.045 6 14500 7000 2700 4,5 123 Constant pressure/load-sensing
Hydrostatic 10 168 38,4 Motomit 4 100-500 Clearcut/Thinning Not manufactured any more
Mefor-Fendt 395 GHA harvester
450 0.055 4 8200 8300 2380 5,8 88 7,5 69 200/300
Mefor-Fendt 380 GTA harvester
400 0.060 4 6700 4750 2100 4,7 59
Relieved constant pressure/load-sensing 6,5 55
16 Harvemeter 4W50, volume measuring
300
Mefor-Fendt 380 Metsänpoika
4 6000 6700 2100 4,6 59 Open system
Mechanical/ hydrostatic-mechanical additional
No
6 30 8,7 ARSCA Electro
Thinning
Nokka 16 WD 400 0.053 6 7500 5160 1060 4,0 84 7,3 75 22 200
Not manufactured any more
Nokka Profi 500 0.043 6 11500 6300 2500 Front and rear
4,75 95 8.0-9,5 120 28 200/300
Nokka Profi Smart 500 0.050 6 10000 6300 2300 Front and
rear 4,65 95
Relieved constant pressure/load-sensing
Hydrostatic No
8,0-9.5 75 22
Epec 4W50/Motomit 4
200
Thinning
Pika 854 550 0.048 11500 6200 2640 5,5 113 100-300 100-400 Thinning/clearcut
Not manufactured any more
Pika 8500 600 0.050 6 12000 6750 2600 6,0 113
9,3 135/ 186 35/42 100-400 100-500 100-600
Clearcut/thinning Not manufactured any more
Pika 856 Classic 650 0.047 6 13750 6300 2700 6,5 113
No
10 180 42
Motomit 4
100-500 100-600 Clearcut/thinning
Pika 956 Verticab 650 0.047 6/4 13850 6720 2640
Front and rear
Front and rear
113
Load-sensing Hydrostatic-mechanical
Yes 10 180 42
62
AVAILABLE CRANES
Dimensions mm Tire options Torque kNm MACHINE
Max. felling diameter mm
Ratio max. felling diameter/weight
Number of wheels
Weight kg
Length Width 500 600 700 800
Turning radius m
Engine output kW
Hydraulic system Transmission Autobalancing
system reach m lifting turning
Measuring system Optimal tree-size l
Optimal work Further information
Ponsse Cobra HS 10 650 0.048 8 13600 7160 2590 6.6 157
Constant pressure/load-sensing
Hydrostatic-mechanical No 10 155 38 Ponsse Opti 0-2700
0-3300 Clearcut/thinning Not manufactured any more
Ponsse Beawer 600 0.048 6 12500 6870/7070 2600 Front
Front and rear
6.6 125 10
Ponsse Ergo 700 0.042 6 16800 7680 2670 Front and rear
6.6 180 10 190 Clearcut
Timberjack 1470 650 0.037 6 17700 7705 2990
Front and rear
183 Load-sensing Yes 9.3/10 178 43.6
Timberjack 1270 C 650 0.038 6 16900 7205 2680/2860
Front and rear
Front and rear
163 Power-controlled/load-sensing
Hydrostatic-mechanical No 8,6/10 178 43.6 Tj 3000 80-1200 Clearcut/thinning
Timberjack 1070 550 0.041 6 13500 6550 2620-2780
Front and rear, rear also 650
Front 123
Relieved constant pressure/load-sensing
No 8.6/10 135 38,4
Timberjack 770 470 0.044 4 10800 5880 2400
Front and rear 650
82 Load-sensing No 7,9 95 24 80-600 Thinning
Valmet 901 2 4WD 480 0.035 4 13600 5830 2650
Front and rear
5.925 95 9,6/10 102/ 136 100-500 Thinning/clearcut
Valmet 911-4 600 0.039 4 15200 6110 2750-2900 Front and rear
Front and rear
5.925 8.7-10 148/ 136 100-500 250-800
Valmet 911-6 600 0.036 6 16900 6890 2750-2900 Front and rear
Front and rear
6.225
129
Yes
8.7-10 148/ 136
33
100-500 250-800 >400-1000
Clearcut/thinning
Valmet 921 640 0.033 6 19300 7450 2990 Front 650 Rear 155
1-district Load-sensing Hydrostatic
Yes 8,7-10 168/ 178 39
Valmet MaxiHarvester
>400-1000 Clearcut
Valtra Forest 400 0.047 4 8500 2245-2600 4,5 85
Relieved constant pressure/load-sensing
Hydrostatic-mechanical No 8,0 60 22 Several alternatives 200 Thinning
TBM 84/1 450 0.049 6 9100 5900 2450 Front 550 Rear 5,4 88 Power-controlled/load-sensing
No 8 95 24 Epec 4W30 Thinning
TBM 85/1 450 0.036 6 12400 5900 2520-2700 Front and rear
5,4 133
Hydraulic
9,1 125 38,4 Epec 4W30 300- Thinning/clearcut
TBM 86/1 600 6 Front and rear
165 Hydrostatic DASA 280/380/Epec 4W30 500- Clearcut/thinning
UTC F 1047 600 4 5680 2600 5,0 89 Hydrostatic 8 86
UTC FS 2665 600 6 6840 2700 6,2 126
Volume-adjustable, load-sensing piston pump
Hydrostatic No
10 143 Motomit 4 100-500 Thinning/clearcut
63
MACHINE
Max. felling diameter mm
Ratio max. felling diameter/weight
Number of wheels
Weight kg Dimensions mm Tire options Turning
radius m
Engine output kW
Hydraulic system Transmission Autobalancing
system AVAILABLE CRANES Measuring system Optimal tree-size l
Optimal work Further information
Rottne SMV Rapid TGS 700 0.044 6 or 8
15900 or 17200
Front and rear
Front and rear
8-10 150 25 DSP 4000 (optimization, communication etc.) Clearcut
Two-grip-system, separate felling and processing units
Rottne SMV Rapid EGS 600 0.029-0.042 6 or 8 14200 -
20500
2860
Front and rear
Front and rear
Unloaded constant pressure
Hydrostatic-mechanical, power control
No
10 200 40 DSP 4000 (optimization, communication etc.) Clearcut/thinning Single-grip
harvester
Rottne 5005 600 0.040 4 15000 2700 Front and rear
Front and rear
138
Hydraulic pump mounted in transfer case with mechanical clutch
10.3 150 32 Rottne D4 Late thinning/final feling
Rottne 2004 450 0.074 4 6050 1840 Front and rear
Front and rear
Front and rear
93 Disengagble tandem-mounted hydraulic pump
Hydrostatic Yes
7 53 12 DSP 4000 (optimization, communication etc.) Thinning
Individually adjustable wheel arms
Rottne H-20 750 0.041 6 18500 8600 3000
Front 750, rear 700
187 Yes 10 200 40 Rottne D4 Clearcut
Gremo 950 HPV 600 0.043 8 13970 7490 2600 or
2760 Front and rear
Front and rear
7,5 or 6,35 bogie lifted
123 Load-sensing Hydrostatic-mechanical No 10 125 DASA 4 Thinninng/clearcut
Sampo Rosenlew SR 1046/1046X
400 0.057 4 7000 4600 2100-2300 Front and rear Front 4,7 73,5 Load-sensing Hydrostatic-
mechanical No 6/7 52 16 Harvemeter 4W50 200 Thinning
Silvatec 886 TH 8 14900 7650 250 Front and
rear
Front and rear
Front and rear
150 Load-sensing/constant pressure
Hydrostatic-mechanical No 8.8/10.1 131 39
Silvatec 896 TH 635 0.038 8 16540 7700 262 Front and
rear
Front and rear
Front and rear
150/190 Load-sensing/constant pressure
Hydrostatic-mechanical No 8.6/10.1 172 46 TM 2000/125/130
ProSilva Ässä 810 450 0.045 4 10000 5300 2400-2950
Front and rear
4.65 114 Load-sensing Hydrostatic No Scaanmat/Motomit/Epec 300 Thinning
Tigercat-Hemek H 09 410 8 1900
Front and rear 400/500/550
101 No 6.6/7.5/8.7 66 16 Thinning Liftable bogies
Tigercat-Hemek H 16 6 8135
Front and rear
Front and rear
181
Load-sensing
Hydrostatic-mechanical with HTC control equipment Yes 110 34
Dasa 380
Clearcut
COMBI-MACHINES AVAILABLE CRANES
Dimensions mm TYre options Torque kNm MACHINE
Max. felling diameter mm
Ratio max. felling diameter/weight
Number of wheels
Weight kg
Length Width 500 600 700 800
Turning radius m
Engine output kW
Hydraulic system Transmission Autobalancing
system reach m lifting turning
Measuring system Optimal tree-size l
Optimal work Further information
RCM remote controlled 4 <3500 3960 1800 1,9 35 Load-sensing Hydrostatic No 3,1 Epec 4W30 First thinning Combi
Pika Combi Trac 550 0.041 8 13500 8360 2600-2800 6,5 115 10 135 50-200
100-400 Thinning Combi
Pika 728 T (combi) 400 0.035 11500 8200 2600 5,5 115
Volume-adjustable, load-sensing piston pump
Hydrostatic-mechanical
9,3-10,5 72/99 35/42 Motomit 4
50-200 Thinning Combi
64
Specifications for fowarders MACHINE Ratio loading
capacity/ net weight Ratio tractive force/ total weight
Loading capacity kg
Total weight kg
Net weight kg
Weight distribution (empty)
Tyre options DIMENSIONS mm Engine output kW
Tractive force kN
Transmission Hydraulic system
CRANE
Front Rear 600 700 800 Length Width lifting torque kNm
reach m
Cat 554 0.8 5.6 10000 22000 12000 8400 3600 Front and rear
Front and rear
8638 2590 91 123 Hydrostatic Load-sensing 63 8.5
Cat 574 0.9 5.6 14000 30000 16000 9600 6400 Front and rear
Front and rear
9360 2830 122 167 Hydrostatic Load-sensing 66 10
Farmi Track 775/975 0.6 4,4/5,7 6000 15950 9950 9060 2200 75 70/91 Hydrostatic-mechanical
Load-sensing/relieved constant pressure
52 8
Logset 3-F 1.0 6.4 9500 19400 9900 6000 3900 Front and rear
Front and rear
8290 2550 81 125 Hydrostatic Load-sensing 60 9.2
Logset 4-F 0.8 5.9 10000 22000 12000 7000 5000 Front and rear
Front and rear
8956 2460 91 130 Hydrostatic-mechanical
Load-sensing 60 9.2
Logset 5-F 0.8 5.9 11000 25500 14500 8250 6250 Front and rear
Front and rear
8956 2500 91 150 Hydrostatic-mechanical
Load-sensing 77 9.3
Logset 6-F 0.8 6.1 12000 27000 15000 8500 6500 Front and rear
Front and rear
9680 2870 123 165 Hydrostatic-mechanical
Load-sensing 99 10
Logset 8-F 0.9 5.7 14000 30000 16000 9500 6500 Front and rear
Front and rear
10000 2940 123 172 Hydrostatic-mechanical
Load-sensing 99 10
Logset 6-E 0.8 5.9 12000 27500 15500 9680 2870 123 161 Hydrostatic-mechanical
Load-sensing 99 10
Pika Classic 728 0.9 6.0 10000 21500 11500 7000 4500 Front and rear
8120 2600 113 130 Hydrostatic-mechanical
Load-sensing 59 10
Pika Classic 826/Verticab 828
0.9 5.4 12000 26000 14000 7500 6500 Front and rear
8600-8860 2500-2980 113 140 Hydrostatic-mechanical
Load-sensing 66/80/100
10
Gremo 950 8-wheeled 0.9 4.6 10000 21185 11185 Front and rear
Front and rear
7960 2600 or 2760 106 98 Hydrostatic Load-sensing 59 6,5
Ponsse Caribou S10 0.8 5.7 10000 22800 12800 8300 4500 Front and rear
Front and rear
8790 2587 125 130 Hydrostatic-mechanical
Relieved constant pressure
95 7.3/9.1
Ponsse Bison S15 0.8 5.9 12000 26900 14900 7500 7400 Front and rear
Front and rear
9000-10000 2780/2810 125 160 Hydrostatic-mechanical
Load-sensing 95/124 7.3/9.1/7.8/10
Ponsse Buffalo S16 0.9 6.0 14000 29900 15900 9530 6370 Front and rear
Front and rear
9800 2960 157 180 Hydrostatic-mechanical
Load-sensing 95/124 7.3/9.1/7.8/10
Tigercat-Hemek F 700 14000 Front and rear
Front and rear
8630 147 160 Electro-hydraulic operated powershift gearbox with torque converter
Load-sensing 6.85
Tigercat-Hemek F 14 H/C/HP/CP
165 172
Tigercat-Hemek 1018 18000 Front and rear 650
Front and rear 750
3.2 11.5 180 Variable speed hydrostatic
7.5
Timberjack 810B 0.8 5.8 8500 18900 10400 Front and rear
Front and rear
7959/8624 2520 81 110 Hydrostatic-mechanical
Load-sensing 64 6.5/8.7/9.6
Timberjack 1010B 0.8 6.4 10000 22000 12000 Front and rear
Front and rear
9000 2700/2880 82 140 Hydrostatic-mechanical
Load-sensing 91 7.2/8.5/10
Timberjack 1110 6-wheeled 0.9 6.4 11000 23600 12600 Front and rear
Front and rear
8910/9170 2680/2860 113 150 Hydrostatic-mechanical
Load-sensing 99 7.2/8.5/10
8-wheeled 0.8 5.9 11000 25300 14300 Front and rear
Front and rear
Timberjack 1410 6-wheeled 1.0 6.1 14000 28500 14500 Front and rear
Front and rear
9205/10405 2890/3070 129 175 Hydrostatic-mechanical
Load-sensing 110 7.2/8.5/10
8-wheeled 0.9 6.9 14000 30000 16000 Front and rear
Front and rear
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MACHINE Ratio loading
capasity/ net weight Ratio tractive force/ engine output
Loading capasity kg
Total weight kg
Net weight kg DIMENSIONS mm
Engine output kW
Tractive force kN Transmission Hydraulic
system CRANE
Length Width lifting torque kNm
reach m
Timberjack 1710 6-wheeled 1.0 5.9 17000 34000 17000 front 700, rear 650/750
10050 2990 160 200 Hydrostatic-mechanical
Load-sensing 151 7.2/8.5
8-wheeled 0.9 5.6 17000 35500 18500 front and rear 650/750
Valmet 830 0.9 4.7 9000 19500 10500 Front and rear
Front and rear 8122 2600 80 91 Hydrostatic
Relieved constant pressure
67 6.8-9.3
Valmet 840.1-S2 6-wheeled 0.8 5.5 11000 24000 13000 Front and rear 8707 2620 94 132 Hydrostatic-
mechanical Load-sensing 77 7,2-9,1
8-wheeled 0.7 5.1 11000 26000 15000 Front and rear
Valmet 860 6-wheeled 1.0 5.7 14000 28300 14300 Front and rear 9170 2730 125 160 Hydrostatic-
mechanical Load-sensing 87 7,2-9,2
8-wheeled 0.9 5.4 14000 29900 15900 Front and rear
Valmet 890 6-wheeled 1.0 5.9 16000 31600 15600 Rear 650 Front 9708 2995 154 186 Hydraulic Valmet Sauer DTC
Load-sensing 77 7,2-9,2
8-wheeled 1.0 5.2 18000 36000 18000 Front and rear 650
Front and rear 750
Dasser ts 6-wheeled 0.0 8500 8500 91/115/136 Hydrostatic-
mechanical
Load-sensing, constant pressure with adjustable pump
100 7.2-10
8-wheeled 0.0 10000 10000
Dasser tsh 8-wheeled 0.0 12000 12000 115/136 100 7.2-10
Dasser trs 8-wheeled 0.0 10000 10000 91/115/136 100 7.2-10
UTC 6/8-wheeled 7850 2500 89-136 Powershift transmission 69 7.2
Rottne Rapid 6-wheeled 0.9 5.0 12000 24800 12800 Front and rear
Front and rear 8810 2650 93 125
Hydrostatic-mechanical, power control
Unloaded constant pressure, disengagable hydraulic pump
60 6.9/7,5
8-wheeled 0.8 4.7 12000 26400 14400
Rottne SMV Rapid 6-wheeled 1.1 5.1 16000 31100 15100 Rear Front and rear 9600 2880 138 160 90 7,1
8-wheeled 0.9 4.8 16000 33500 17500 Front and rear
Front and rear
Rottne Solid F9 8-wheeled 0.8 4.9 9000 20500 11500 Front Front and rear 8513 2480 93 100
Load-sensing, constant pressure
60 6,9
Rottne Solid F12 6-wheeled 0.9 6.1 12000 25500 13500 Front and rear
Front and rear 9650 2550 122 155 72 6,9
8-wheeled 0.8 5.8 12000 26900 14900
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APPENDIX 2: CALCULATED NOMINAL GROUND PRESSURES (NGP) FOR A RANGE OF FOREST MACHINES Machine Type Empty Payload Total No. Tyre Size Radius Tyre Band Tracks Duals Tyre+Track Track NGP (f=forwarder) weight weight wheels Width fitted or not width c-c
(h=harvester) kg kg kg m mm Yes/No Yes/No mm m kPa Gremo 950 HPV (f) 10800 10,800 8 600/50-22.5 0.585 600 No No 38 Gremo 950 HPV (f) 10800 6,000 16,800 8 600/50-22.5 0.585 600 No No 59 Gremo 950 HPV (f) 10800 10,800 8 700/45-22.5 0.585 700 No No 32 Gremo 950 HPV (f) 10800 6,000 16,800 8 700/45-22.5 0.585 700 No No 50 10800 6,000 16,800 8 700/45-22.5 0.585 700 No No 50 Gremo 950 HPV (h) 14000 14,000 8 600/50-22.5 0.585 600 No No 49 Gremo 950 HPV (h) 14000 14,000 8 700/45-22.5 0.585 700 No No 42 Valmet 840 (series 2) (f) 15000 15,000 8 600/50-26.5 0.667 600 No No 46 Valmet 840 (series 2) (f) 15000 8,000 23,000 8 600/50-26.5 0.667 600 No No 70 Valmet 840 (series 2) (f) 15000 15,000 8 700/45-26.5 0.667 700 No No 39 Valmet 840 (series 2) (f) 15000 16,500 8 700/45-26.5 0.667 700 4 band tracks No 900 1.51 25 Valmet 840 (series 2) (f) 15000 8,000 24,500 8 700/45-26.5 0.667 700 4 band tracks No 900 1.51 37 Timberjack 1070 (h), 6 wheel 13500 13,500 4 700/45-22.5 0.585 700 No No . 2 650-26.5 0.666 650 No No 53 Timberjack 770 (h) 10800 10,800 4 650-26.5 0.666 650 No No 61 Timberjack 810-B (f) 10500 12,000 8 600/50-22.5 0.585 600 No No 42 810-B (f)+Tracks 10,500 12,000 8 600/50-22.5 0.585 600 4 tracks over 8 wheels No 1.3 24
810-B + tracks and duals 10500 13,500 8 600/50-22.5 0.585 600 4 tracks + extra wheels Yes
400mm 1150 1.3 17 Valmet 860 (f) 15900 15,900 8 700/45-26.5 0.666 700 No No 42 Valmet 860 (f) 15900 8,000 23,900 8 700/45-26.5 0.666 700 No No 63 Valmet 860 (f) 15900 17,400 8 700/45-26.5 0.666 700 4 tracks over 8 wheels No 900 1.51 26 Valmet 860 (f) 15900 8,000 25,400 8 700/45-26.5 0.666 700 4 tracks over 8 wheels No 900 1.51 38 Valmet 911 (h), 6 Wheel 14500 14,500 4 700/45-22.5 0.585 700 No No . 2 700/50-26.5 0.666 700 No No 55 Valmet 911 (h), 6 wheel 14500 15,500 4 700/45-22.5 0.585 700 Tracks on 2 bogies No 900 1.3 . 2 700/50-26.5 0.666 700 No No 40 Valmet 911 (h), 6 wheel 14500 15,500 4 700/45-22.5 0.585 700 Tracks on 2 bogies No 900 1.3 . 2 700/50-26.5 0.666 1170 Duals, extra 400mm Yes 1170 35
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Where: w = vehicle weight r = tyre radius b = tyre width n = number of tyres
For band tracks: NGP = W/A Where A = tyre/soil contact area, and is given as: A = b(1.25r+L)
Some examples of tyre dimensions
where L = distance between centres of the bogie axles (i.e. c-c in the drawing)
For example:
Tyre Size Diameter (mm)
Radius, r (mm)
Width, b (mm)
c-c for 22.5 tyres (as fitted on Timberjack 810B) = 1.3m 600/50-22.5 1170 585 600
c-c for 26.5 tyres (as fitted on Timberjack 1210B) =1.51m 700/45-22.5 1170 585 700
700/50-26.5 1333 666 700
600/65-34 1650 825 650
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ADDENDUM: GENERAL STATISTICS ON FORESTRY OPERATIONS IN THE ECOWOOD PARTNERSHIP COUNTRIES (FINLAND, IRELAND, ITALY AND SPAIN)
after: Lyons (2002)9 Table 1. Forest data and ownership in the ECOWOOD Project partner countries Description Country Finland Ireland Italy Spain Forest data Forest area (ha) 23,000,000 641,250 8,000,000 13,904,660 Percentage (%) of total country area
75.4 9.0 21.0 27.5
Productive area (ha)* 19,600,000 - - - Percentage of total country area 64.3 - - - Productive % of forest area 85.2 - - - Forest area on sensitive sites (ha) 4,600,000 160,000 - - Sensitive sites % of forest area 20.0 25.0 - - Ownership State (%) 27.6 68.0 40.0 32.6 Private (%) 61.1 Company (%) 8.9 32.0 60.0 67.4 Others** 2.4 * The productive forest is defined as managed forests with a minimum growth rate of 1 m3/ha/year ** The others category includes forest area owned by cities, villages, and churches The dash (-) denotes lack of data Table 2. Examples of sensitive forest sites in partner countries, and problems associated with the use of wood harvesting and extraction machines on the sites Country Examples of sensitive forest sites Problems associated with the use of
wood harvesting machines on the sites Finland Peatlands; most of spruce forests; wet and
soft soils Risk of butt rot root damages; deep ruts and excessive machine sinkage (especially during the snow-free season)
Ireland Forest on low bearing capacity soils (peat and wet gleys); forests besides fish populated watercourses; forest and peat soils with bedrock of low-buffering capacity; natural woodland broadleaf forests
Unpredictability of weather patterns; lack of contingency harvest plans; diversity of machines used by contractors; lack of grant aid for additional eco-efficient measures (e.g., tracks, wider tyres, mobile bridges, pollution kits)
Italy Mountain forests; forests on steep slopes (52% of the forests are located on land with slopes greater than 40%)
Soil erosion; solid transport; landslides
Spain Forests for erosion protection that are located on steep slopes with erosion prone soils
Use of ground-based systems on steep terrain; high costs associated with the use of cable systems
9 Based on a questionnaire by Lyons (2002) Lyons, J (2002) Current wood harvesting practices on sensitive forest sites in the ECOWOOD project partnership countries. www.ucd.ie/~foresteng
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Table 3. Inventory data for the ECOWOOD Partnership countries Description Country Finland Ireland Italy Spain Availability of harvesting and extraction route network data (%)
100 100 83 50
Existence of environmental and terrain constraints data
yes yes yes some
Rate of updating forest data 1 year in 10 Annually 1 year in 10 1 year in 10 Data updated by Finish forest
research institute
Forest professionals
Contracted consultants
Forest state administration
Average forest size (ha) 26 19,000∗ NA Range in size of compartment (ha) 1–10 5–10 20–30 5 Range in size of sub-compartments (ha) 0.5–5 0.5–20 2–10 - NA, not applicable ∗Forest Management Units range from 8 to 30 kha. Countryside units of 1 kha are being developed. Note: Public or state owned forests in Ireland have good inventory. The national forests are mapped by the Irish Forest Service and Coillte (Irish Forestry Board). Privately owned forests are developing and no inventory is done for these forests. In Italy, public forests are more likely to be under a forest management plan, which includes inventory data. On the other hand, private forests are often too small to have much economic importance, and therefore owners have little interest in updating either the inventory or the management plan. In Finland, forest management plans cover most of the country. Table 4. Yield class (m3/ha.year) of principal tree species in the ECOWOOD Partnership countries Tree species Country Finland Ireland Italy Spain Range Average Range Average Range Average Range Average Spruce 1–6 4 4–28 16 2–15 8 10 Pines 1–6 4 4–18 14 4–12 7 1.5–20 - Larch 4–14 14 5-10 Birch 1–6 6 Chestnut 4–20 10 1-3 Beech 2–6 3 4-8 Eucalyptus 10–20 - Populus 10–20 - The dash (-) denotes lack of data Table 5. First thinning, age (years), mean Dbh (mm) and volume (m3/tree) of tree species in the ECOWOOD Partnership countries Tree Country species Finland Ireland Italy Spain Age Dbh Vol Age Dbh Vol Age Dbh Vol Age Dbh Vol Spruce 30 120 0.07 18-22 160 0.12 25 140 0.11 Pines 30 120 0.07 18-22 160 0.12 25 130 0.07 *10–35 - - Larch 18-22 160 0.12 Birch 30 - - Chestnut Beech 35 150 0.14 Eucalyptus - - Poplar - - Dbh, diameter at breast height; V, volume The dash (-) denotes lack of data
70
Table 6. Final felling age (years), mean Dbh (mm) and volume (m3/tree) of tree species in the ECOWOOD Partnership countries Tree Country species Finland Ireland Italy Spain Age Dbh V Age Dbh Vol Age Dbh Vol Age Dbh Vol Spruce 80–130 230–300 0.5 40–45 300 0.4 100 400 1.40 70-120 Pines 80–160 230–310 0.5 40-45 300 0.4 85 330 1.00 ~40 - - Larch 40-45 300 0.4 Birch 60–80 230–300 - Chestnut 18? 140 0.12 80/100 Beech 100/120 Eucalyptus 12-30 - - Poplar 10/30 - - Dbh, diameter at breast height; V, volume The dash (-) denotes lack of data Table 7. Prevalence and ownership of mechanised and motor-manual harvesting systems in the ECOWOOD Partnership countries Description Country Finland Ireland Italy Spain 1) Type of harvesting system • Shortwood (%) 100 97 98 90–95 • Tree length (%) 2 1 5–10 • Full tree (%) 1 1 2) Mechanisation • Motor-manual (%) 5 3 94 20 • Mechanised (%) 95 97 6 80 • Purpose-built wheel based harvesters (%) 100 60 65 - • Excavator-based harvesters (%) 40 35 - 3) Type of extraction system • Cable system (%) 2 4 • Purpose-built forwarders (%) 100 88 2 85–90 • Tractor-trailers (%) 2 52 • Skidders: tractor + winch (%) 8 39 10–15 • Others* (%) 3 4) Timber volume removed by • Thinning (%) 50 40 - 50 • Clearfell (%) 50 60 - 50 5) Harvesting machine ownership • Forest owners (%) 2 5 • Private contractors (%) Mainly 98 Mainly 95 • State (%) 6) Miscellaneous • Need for further specialised machines No Yes Yes Yes • Local manufacture of harvesting machines Yes No Yes Yes (5%) • Existence of significant machine development Yes No Yes Yes *Others include draught animals Table 7 further shows that private contractors own the largest proportion (above 95%) of the harvesting and extraction machines in all the countries. It was noted that there is need for specialised machines in Ireland (more cable systems; lightweight forwarders), Italy (steep terrain and low impact harvesting systems) and in Spain (specialised machines that can adapt to difficult terrains). Italy is involved in significant design/develop of cable yarders, and their future machine development expectations concern Italian-built prime-mover for harvester units.
71
Table 8. Operation requirements for wood harvesting and extraction systems in the ECOWOOD Partnership countries Operation requirements Country Finland Ireland Italy Spain 1) Existence of flexibility in timing of operation Yes Yesa) Partial - 2) Shortage of mechanised harvesting capacity No Yesb) Yesd) 3) Method of wood extraction in thinning operation • Follow-defined tracks (line selection) Yes Yes
(Mostly) • Random tracks with selection Yes • Forwarders use harvester tracks Yes Yes 4) Range of extraction distance (m) 100–2000 50–1000 25–3000 0–1000 5) Average extraction distance (m) 300 200 600 500 6) Range of number of forwarder passes 1–20 1-20 - 7) Average number of forwarder passes 10 6 - 8) Type of harvester traction mechanism used • wheel chains All round partially • band tracks Partially Partially 9) Type of forwarder traction mechanism used • wheel chains All round yes • band tracks Partially 10) Availability of grant/aid for machine purchase No Not now Yesc) Not now 11) Computation of ground contact pressures No No - No 12) Percentage of trained operators (%) 100 90 100 13) Percentage of certified operators (%) 15e) 0 14) Operator competence • Unskilled (%) 5 33.3 • Semi-skilled (%) 15 33.3 • Highly-skilled (%) 100 80 33.4 15) Payment method for operator Hour 30 40 - Day-shift/bonus 70 60 - a) Some wet sites are classified as Summer only (drier, Irl) or Winter only (firmer, Finland) b) Occurs in steep sites for lack of cable systems and labour c) Depending on regional requirement can amount to about 30% or more d) Unavailability of suitable machines that can be adapted to operate on the steep terrain e) Certification scheme commenced and will be circa 40% by end 2002
72
Table 9. Management of wood harvesting and extraction operations in the ECOWOOD Partnership countries Management Country Finland Ireland Italy Spain 1) Consultations prior to harvesting • With locals Yes Seldom Yes • With statutory bodies Yes Yes Always Yes 2) Site supervision methods • Operator interfaces with a manager Daily Daily Daily • Operator uses a mobile phone Daily Daily Daily Daily 3) Site supervision done by • Forest owner Yes • Purchaser Yes Some Yesb) Yes • Contractor Some 4) Updating of inventory data after harvesting • Companies Yes • Harvest manager Yes • Forest owners association Yes • Statutory board Yesa) • Forest technician Yes • Public administration Yes 5) Harvesting plan prepared by: • Companies Yes • Forest owner associations Yes • Forest manager Yes • Contractor • Certified forest consultant Yesc) 6) Monitoring of harvested stocks • Measured randomly on site visits Yes Yes Mostly Yes • Estimated on site visits Yes • From harvester head data Mostly commencing commencing • Operator estimates Occasionally • Measure at the mill Yes Yes Yes • Mobile text estimates Occasionally 7) Accuracy of information provided on stocks > 95% ~ 90% Dependsd) 90–95% a) Irish Forest Board (Coillte) b) Based on their needs c) If lot is larger than 5000 m2 d) Depends on the method, which in turn depends on the value of the stock
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Table 10. Operation requirements for system productivity in the ECOWOOD Partnership countries Operation requirements Country Finland Ireland Italy Spain 1)Estimate of Wood harvested (%) from sensitive sites during thinning and final felling operations
15/20 ~30 NA ~ 80
2) Reduction of machine output on sensitive sites slightly Yesa) Yes slightly 3) Logs cut to: • Standard lengths Yes Yes Yes Yes • Individual customer specifications Yes Yes Yes • Random lengths (m) 3.7-6.1 4) Common range of log lengths (m) 4–6 2.5–5.5 1–4 2–2.2 5) Timber sold standing (%) 73 48 ~ 100 100d) 6) Machine operators operating on shift work (%) 30 5 NA - 7) Operator working hours per day • Harvesting 10 10 7–10 8–10 • Extraction 10 10 7–10 8–10 8) Wood owner payment basis for timber harvested • Volume of wood cut Yes Yes • Measured at weigh-bridge Yes Yes Yes • Scanned in sawmills Yes • Estimated Yes 9) Improvements in productivity expected from; (i) Technology • Short term Yes • Medium term Telemetrics Yes Yes • Long term Yes (ii) Systems and planning • Short term Yes Yes • Medium term Yes Yes Yes • Long term Yes Yesb) Yes (iii) Operator competence • Short term Training Yes yes • Medium term Yes Yes Yes • Long term Yes Yes 10) Improvements in quality expected from; (i) Technology • Short term Yes • Medium term Yes Yesc) Yes Yes • Long term Yes (ii) Improvements from Systems and planning; • Short term Yes Yes Yes • Medium term Yes Yes Yes Yes • Long term Yes yes Yes a) Sometimes if harvest manager requires changes to normal operations (e.g., use of deep brash mat, temporary stream crossings.) b) Harvest/scheduling Sales lot formation c)Harvesting Head calibration d) Unless the forest is owned by the mill
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Table 11. Environmental concerns in wood harvesting and extraction operations in the ECOWOOD Partnership countries Environmental concerns Country Finland Ireland Italy Spain 1) Existence of data on extent of rut formation on particular sites with respect to:
• Number of machine passes - some No No • Axle loads - No No No • Ground contact pressures - No No No 2) Level of soil erosion, scuffing, siltation and leaching into waterways in thinning/final felling
Lowa Lowb) - Low
3) Level of damage to residual stands during thinning operations
1.6-5.1% - - -
4) Types of lubrication oils used (i) In bar and chain systems • Biodegradable (%) 100 3c) NA • Non-biodegradable (%) 97 NA Yes (ii) In machine hydraulic systems • Biodegradable (%) 70 2 NA • Non-biodegradable (%) 30 98 NA Yes 5) Lack of suitable machines for sensitive sites - Yes No Yes 6) Existence of guidelines on excessive environmental and residual stand damage
Yes Yesd) Yes Yes
7) Acceptable level of damage determined by: • Regional Forest Centres Yes • Harvest manager Yes • Forest service personnel Yese) 8) Existence of DSS to minimise negative impacts of harvesting on sensitive sites
No No No No
9) Decision to cease operations if conditions on sensitive site worsen or change made by:
• Operator Yes • Purchaser Yes • Land owner Yes • Harvest manager Yes • Forest service Yes • All parties concerned Yes 10) Operation cessation related costs born by: • Purchaser Yes • Land owner • Contractor Yes Yes Yes 11) Penalties for causing site damage None Yes DSS, decision support systems a) Because of flat terrain b) According to SFM audit on harvesting practices c) Being introduced and will be 100% in 2003 d) Timber harvesting guidelines (Forest Service) e) Based on provincial regulations
