Trees in Hard Landscapes Consultation Draft 28 May 2014

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Treesin HardLandscapesA Guide forDelivery

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Trees and Design Action GroupThe Trees & Design Action Group (TDAG)is a pioneering group of individuals,professionals and organisations fromboth the public and the private sectorswho have come together to increaseawareness of the role of trees in thebuilt environment throughout theUnited Kingdom.

The group shares the collective visionthat the location of trees, and all thebenets they bring, can be securedfor future generations by inuencingthe planning, design, construction andmanagement of our urban infrastructureand spaces.

Now a registered charity, TDAG wasestablished in 2007. It is not-for-prot and apolitical. Its membership,online publications and information

are free. This approach enables TDAGto assimilate ideas and knowledgeindependently of organisationalhierarchy, prot or commercial interests.

More information found at:www.tdag.org.uk

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4/130Trees in Hard Landscapes2 Consultation draftTrees in Hard Landscapes2

Starting from the pointwhere the decision toinclude or retain treesin a new development orretrot scheme has been

made, this guide exploresthe key building blocksfor success.

Maintenance andsustainability considerationsare included throughoutas they are key to ensuringthat the early concept and

vision produce the intendedoutcome over the long-term.

Collaborative ProcessFrom project initiation to maintenanceand monitoring, when, how and withwhom joined-up working needs to happen.

Designing with TreesPractical strategies to ensure trees best

contribute to the delivery of the designobjectives of a project.

Technical Design SolutionsThe available technical design solutionsto build-in success, rather than failure.

Species Selection CriteriaThe frame of reference to use as a basisfor tree selection.

Overview

Multiplebenets

Designobjectives/

brief

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Introduction: the need for sustainableintegrated infrastructureThe purpose of this guide 00The focus of this guide 00The audience for this guide 00How this guide was developed 00

Collaborative

Process 00

Securing value throughout theproject lifecycle 00

1.1 A good start: leadership, valueunderstanding and funding 00

1.1.1 The need for leadership 001.1.2 Integrating trees in the project brief,

value assessment and team 001.1.3 Setting the funding strategy on the

right track 00

1.2 Design: multi-discipline input andholistic above/below-ground response 00

1.2.1 Integrating trees into the audit process 001.2.2 Securing early and substantial input

from the tree specialist 001.2.3 Proactively designing the below-ground

environment 001.2.4 Designing with maintenance in mind 001.2.5 Capitalising on trees for community

consultation and planning permission 00

1.3 Implementation: joined-up worksequence and site supervision 00

1.3.1 Selecting and managing contractors 001.3.2 Optimising the work sequence 001.3.3 On-site presence and supervision 00

1.4 Maintenance and monitoring: closingthe value loop 00

1.4.1 Post-establishment maintenance is key 001.4.2 Monitoring and continuous learning 001.4.3 Innovative approaches to contracts 00 In Summary and References 00

Designing with Trees 00

Using trees as a positive asset 002.1 Effective use of space and sense 00

of place2.1.1 Making space for trees: a shared 00

responsibility2.1.2 Adapting tree choices to local conditions 002.1.3 Tree and local distinctiveness 002.1.4 Tree for immediate (and lasting) impact 002.1.5 Tree strategies for year-round impact 00

2.2 Safe movement for all 002.2.1 Trees and urban road safety 002.2.2 Trees for trafc calming 002.2.3 Trees for inclusive walking and cycling 00

2.3 Unobstructed splays 002.3.1 Trees and junction visibility splays 002.3.2 Trees, commercial signs and shop 00

window visibility2.3.3 Trees, lighting and CCTV 00

2.4 Water sensitive design 00

2.5 Safety, health and comfort 002.5.1 Trees and public safety 002.5.2 Trees and peoples health 002.5.3 Trees and air quality 002.5.4 Trees, temperature and wind control 002.5.5 Trees and wildlife health 00

2.6 Surface treatment, cleaning and 00de-icing

2.6.1 Leaf fall and droppings 002.6.2 Surface treatment and cleaning options 002.6.3 De-icing salt 00

2.6 Surface treatment, cleaning andde-icing 00

2.6.1 Leaf fall and droppings 002.6.2 Surface treatment and cleaning options 002.6.3 De-icing salt 00 In Summary and References 00

Technical Design Solutions 00

Building-in sustainable success 003.1 Basic tree knowledge for success 003.1.1 Terminology 003.1.2 Why longevity matters 003.1.3 Roots, oxygen and rooting volume 003.1.4 Dispelling the topsoil myth 003.1.5 Securing access to water 003.1.6 Above-ground protection3.1.7 Implications for tree rooting 00

environment design

3.2 Load-bearing 003.2.1 Structural substrates 003.2.2 Crate systems 003.2.3 Raft systems 00

3.3 Integrity of surfaces and above ground 00structures

3.3.1 Tree-based strategies 003.3.2 Infrastructure-based strategies 003.3.3 Addressing existing damage by roots 003.3.4 Subsidence 00

3.4 Underground utilities 003.4.1 Documenting and optimising the use 00of below-ground space

3.4.2 Avoiding indirect damage 003.4.3 Avoiding direct damage 00

3.5 Sustainable urban drainage 003.5.1 Key considerations for success from 00

design to delivery3.5.2 Design options for managing surface 00

water runoff with treesIn Summary and References 00

Species Selection Criteria 00

Asking the right questions to get theright answers

4.1 Key site constraints 00

4.2 Ecological resilience requirements 00

4.3 Desired aesthetic and functional 00attributes

4.4 Shortlist of options and customer 00feedback

4.5 From tree choice to tree specications 00 In Summary and References 00

Case study nder 00Glossary 00Financial support 00Acknowledgements 00Afterword 00

Contents


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Trafccalming

Enjoyable journeys

Enhancedwalkingenvironment

21st century opportunitiesand challenges

Designingwith TreesThe inclusion or retention of trees is bestapproached as a means to an end ratherthan as an end in itself. Achieving long-term benets and value from trees requiresa concerted strategy. This guide explorescurrent evidence on the enabling factors thatturn trees into functional components of thehard landscapes in which they grow.

CollaborativeProcessWeaving natural resources, especiallytrees, into the built environment requires across-disciplinary collaborative approachfrom project initiation through to design,implementation, maintenance and monitoring.This guide looks at when, how and withwhom joined-up working needs to happen.

Trees in Hard Landscapes4

Integration of treesand sustainable

drainage eg swalesand structural soilProtection andaccess to utilities

Collaborativeapproach to fundinggreen and greyinfrastructure

Cooling andsheltering

Longevity for treesand surroundinginfrastructure

Efcient projectdelivery

Attractive retailenvironment

Adequate substrate forroot development eg crate

Time in Years

6025

5

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Communityinvolvement withurban orchard

Colourfulseasonaldisplays

Technical DesignSolutionsDesign of the below-ground environmentis key to achieving long-term compatibilitybetween trees and the built infrastructurethat surrounds them in towns and cities.This guide examines innovative and availabletechnical solutions to help build lastingsuccess from investing in trees.

Species SelectionCriteriaWhile tree species selection alone cannotmake up for a poor design strategy orinadequate underground growing conditions,choosing the right tree for the right place isan essential nal ingredient for success. Thisguide offers a ve-step process for makingthe best shortlist of available options andachieving resilient and successful tree choices.

Trees in Hard Landscapes 5

Integration ofadequate provisionfor trees in theplanning andadoption processes

Resilience to pestsand diseases

Supportingmental health

Air quality

Senseof place

Mindset to trialand learn

Load bearing andnon-compacted

rooting environmenteg rafts

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IntroductionThe need for sustainable integrated infrastructureThe purpose of this guideTrees in Hard Landscapes: A Guide for Delivery explores the practicalchallenges and solutions to integrating trees in 21st century streets, civicspaces and surface car parks. It builds on the principles offered in Treesin the Townscape: A Guide for Decision Makers to provide practitioners

with advice and examples for project delivery, detailing process, designand technical options.

Investments in infrastructure are driven by wide-ranging agendasincluding economic development, health and wellbeing, housing, oodand water quality protection, climate adaptation and mitigation. Ina context in which public resources may be limited and sustainableoutcomes a priority, wise infrastructure investment will seek to satisfymore than one objective at a time. Research and practice demonstratethat, with care and understanding, integrating trees with otherinfrastructure can often help to achieve such a range of benets.

However, the track record for achieving successful and lastingintegration of trees in hard landscapes in the early 21st century hasbeen poor. A comprehensive survey from 2004, published in the 2008DCLG report Trees in Towns II , found a 25% failure rate for new urbantree planting and an average life of 12 years for street trees 1. This isdisconcerting considering that it is only through growth over timethat trees can full their potential to deliver returns on investment.The gures have not been updated in the past decade but the DEFRAcommissioned draft report Barriers and Drivers to Planting and

Retaining Urban Trees (March 2013) also voices strong concerns 2 .

1Department forCommunities and LocalGovernment (2008).Trees in Towns II: ANew Survey of UrbanTrees in England andTheir Condition and

Management. London:Department forCommunities and LocalGovernment

2Found at:www.tdag.org.uk/uploads/4/2/8/0/4280686/btp_barriers_and_drivers_nal_report_march_2013.pdf



The context in which trees can thrivein hard landscapes is in a state ofux, offering new challenges andopportunities for success. With theadvent of cable television and theinternet, there is increased crowdingbeneath our streets. Utility records,where they exist, often present anincomplete and inaccurate picture ofthese networks. The way we use our

streets is changing, with heightenedconsideration for cyclists, pedestriansand public transport. Those whodesign and manage streets areincreasingly looking to local solutionsto accommodate the needs of all users.Finally, with changes to weather patterns,and especially more rainfall, surface watermanagement needs more comprehensiveapproaches. There is evidence frominnovative practices around the worldthat trees can be valuable and versatile

additions to strategies designed toalleviate the pressures on traditionalwater management systems while alsooffering cooling and UV protection whenneeded. Reecting this context and associatedchallenges, Trees in Hard Landscapes shows how different approaches canenable greater long-term compatibilitybetween trees and other infrastructure. Itoffers those directly involved in creatingand managing hard landscapes thecommon language and tools they need toachieve better performance and reducelong-term maintenance costs.

Starting from the point where thedecision has been made to include orretain trees in a new development orretrot scheme, this guide exploresthe key building blocks to doing sosuccessfully, including:1. The role and opportunities for

collaboration to secure better

outcomes and value throughoutthe project lifecycle.2. Practical strategies to ensure trees

best contribute to the delivery ofthe design objectives of a project.

3. Technical design solutions to buildin success.

4. A frame of reference to use whenselecting trees.

Maintenance and sustainabilityconsiderations are included throughoutas they are the key to ensuring thatthe early concept and vision produce asuccessful outcome.

The focus of this guideTrees in Hard Landscapes focuses onhard surfaced areas in urban settingssuch as streets, civic spaces and surfacecar parks. These hard landscapesare arguably the most challengingenvironments for growing trees, but theyare also the areas where much is to begained from their inclusion.

This guide does not advocate thattrees should be planted in every streetor public square, but rather looksat situations where, following dueconsideration of townscape inuencesand the historic environment, a decisionhas been made to include trees. Itdoes not cover trees planted over builtstructures such as basements, or treeson podiums and roof gardens, as theserequire very specic strategies forsuccessful delivery.

The audience for this guideTrees in Hard Landscapes is aimedprimarily at highway engineers, designersand tree specialists. It will also be ofvalue to developers, planners, electedrepresentatives, local communitiesand anyone involved in hard landscapedesign, construction and management.

How this guide was developedTrees in Hard Landscapes was developedby the Trees and Design Action Group(TDAG), in association with the CharteredInstitution of Building Services Engineers(CIBSE), the Chartered Institution ofHighways and Transportation (CIHT), theInstitution of Civil Engineers (ICE), andthe Institute of Chartered Foresters (ICF).The acknowledgements section providesmore details about the wide range ofindividuals and organisations who gavetheir time to steer, review and inform thecontent of this guide. Such a rich cross-disciplinary, knowledge-sharing effort

would not have been possible withoutthe generous nancial support of 37sponsors as shown on page 125.



CollaborativeProcess

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1.1 A good start: leadership, valueunderstanding and funding 00

1.1.1 The need for leadership 001.1.2 Integrating trees in the project brief,

value assessment and team 001.1.3 Setting the funding strategy on the

right track 00

1.2 Design: multi-discipline input andholistic above/below-ground response 00

1.2.1 Integrating trees into the audit process 001.2.2 Securing early and substantial input

from the tree specialist 001.2.3 Proactively designing the below-ground

environment 001.2.4 Designing with maintenance in mind 001.2.5 Capitalising on trees for community

consultation and planning permission 00

1.3 Implementation: joined-up worksequence and site supervision 00

1.3.1 Selecting and managing contractors 001.3.2 Optimising the work sequence 001.3.3 On-site presence and supervision 00

1.4 Maintenance and monitoring: closingthe value loop 00

1.4.1 Post-establishment maintenance is key 00

1.4.2 Monitoring and continuous learning 001.4.3 Innovative approaches to contracts 00 Section Summary and References 00

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Collaborative ProcessSecuring value throughout the project lifecycleWeaving natural resources into the built environment requiresa cross-disciplinary approach.

The Department for Transports Local Transport Note1/08 Trafc Management and Streetscape (LTN 1/08) 3 sets out a generic design and implementation process forhighway schemes from project initiation through to design,implementation, and maintenance and monitoring. This four-step approach can be applied to all types of projects fromnew developments to changes to existing streets and squares.

Informed by the experiences shared by highway staff, designleads and tree specialists during interviews, this sectionoffers suggestions about when, how and with whom joined-up working on trees can t within and contribute to thisexisting framework. Success factors and potential benets arealso highlighted. Where relevant, issues related to planningconsent and infrastructure adoption are discussed.

3

Found at:www.gov.uk/ government/uploads/ system/uploads/ attachment_data/ le/3810/ltn-1-08.pdf



Retail

Retail and Residential



BUSLANE

Square

Deliveries

Retail

Town Hall

L o a d i n

g

Mixed use

Vacant site to beredeveloped fornew retail, ofcesand Park and Ridecarpark

Proposed commonutility service enclosureto be funded byadjacent newdevelopments

Planting deliveredthrough highway-led capitalinvestment toenhance cycling

Trafc calmingproposed. Schemevalue assessmentreects value addedby tree planting

Project managertrained to installload-bearing systemfor tree rootingenvironment

Reducedimplementationcost throughintegrationof highwayengineeringand tree works

CCTV, lighting,drainage, trafcsafety, planner,highway engineer,landscape architect,maintenancemanager and treeofcer jointly agreedesign brief for newdevelopment andPark and Ride

Existingtrees

PedestriansCyclists

Not to scale for illustrativepurposes only

Buses



1.1A good start: leadership, projectteam and funding

1.1.1The need for leadershipAs Trees in the Townscape (Principle 9,pp56-61) highlighted, whether in localauthorities or private organisations,leadership is required to create anenvironment of empowerment, mutualrespect and trust, where there is pridein the inclusion of trees and a positive

attitude towards resolving any conictstheir introduction may generate. A strong message from the top is anenabling mechanism for empoweringindividuals to work as teams andsuccessfully integrate trees in theirprojects. In practical terms, this requires: Clear standards for the protection, care

and planting of trees in the local planand/or other key policy documents,including local transport plans, highwaydesign guides and supplementaryplanning documents addressingtrees in new developments. Suchstandards may equally be set by privateorganisations in corporate policy

documents (see the example of LandSecurities on p23 and Tor Homes onp25 in Trees in the Townscape ).

Personal commitment from the electedand/or executive team to the policiesand standards set.

The interviews conducted for this guideshowed that success in integratinggreen (natural) and grey (engineered)infrastructure delivery also relies onleadership at staff level, including: Arboriculture or design staff who

actively engage in policy work toarticulate the relevance of trees withinbroader strategic policy or businessagendas and place individual decisionswithin the wider framework of theoverall management of the local treepopulation.

Arboriculture and highway staff whofeel condent in overseeing operationaland construction work.

Arboriculture and highway staff whoshare an interest in and appetite forinnovation and learning. This is ofparticular importance when it comesto highways. It ensures that innovativeapproaches such as those designed toenhance the tree rooting environment

Integrating trees into the LTN1/08 design process, ow, inputs and outputs

Applied aboveand below

ground

Including roleof trees

in supportingthe vision

Trained towork with loadbearing rootingenvironments

Tree ofcer,lightingdesigner,CCTV manager,highwaymaintenancemanager,access advisor,utilities,communityrepresentatives

Includingpost-plantingcare (5 yearminimum)

Including trees

Including post-planting care

Includingcanopy coverand tree health

Initial treefeasibility

survey(above and

below ground)

Detailedunderground

survey todelivery

accuracy

Treeprocurement

Tree specialistregularly

onsite



beneath load-bearing hard surfaces canbe examined and, potentially, trialledlocally and embraced. Flexibility inthe use of local standards to guideresponses to proposed design is critical.

1.1.2Integrating trees into the value argumentand team compositionBuilding a shared vision for the tree

project is highlighted in LTN 1/08 (paragraph 2.3) and other guidance as anessential starting point.

For such a vision to provide a robust

platform for later design stages, the rolethat trees and other green componentsare expected to play in supporting thedelivery of agreed objectives needs to bearticulated clearly. This should be seen in: The wording of the project brief . The

brief represents an opportunity toexpress the vision as well as describe

the schemes purpose and desiredoutputs. Existing policies on trees andthe particular role trees may be ableto play in the scheme should be madeexplicit, together with the capacity and

Case study 1Melbournes coordinated approachto streetscape projects

LocationMelbourne, Australia

Melbourne is aiming to double the canopycover from its current 22.5% to 40% in 2040.To achieve this goal, the councils urbanlandscape department, which is leading thestrategic planning, management and capitalinvestment for the citys public open spaces(including parks, gardens and the urbanforest), conducted a comprehensive surveyof all the trees in Melbournes streets. Thesurvey looked at species, size and conditionsto assess the useful life expectancy (ULE)of each tree. This database was then usedto model how the canopy would evolveunder different circumstances, includinga do nothing scenario. The modellingshowed that reaching the 40% canopy covertarget would require planting an average of3,000 trees a year for the next decade. Themodelling did not focus exclusively on treenumbers but also considered how the treeplanting conditions would affect canopysize. The process showed that achieving thetarget set would require moving trees onthe other side of the kerb line, where thereis more adequate below and above space toaccommodate root and crown development,and where it is much easier to give the treesaccess to moisture. Extensive communityconsultation is underway to establish foreach neighbourhood or precincts as theyare locally called a ten-year urban forestplan identifying priority for tree planting andreplacement, how the planting will support

the local unique character of the area, andthe benets to be delivered through theplanting. Delivery of such an ambitiousurban forestry programme would not bepossible without strong interdepartmentalcollaboration. To facilitate this, a streetscapecoordination committee has beenestablished bringing together, on a monthlybasis, the trafc and parking, capital worksand urban landscapes departments. Thecommittee ensures that, wherever capitalor refurbishment work is being planned inthe highway, adequate green infrastructureprovision is integrated into the projects,following the priorities and principles dened

in the precinct plans. It also enables budgetsand community engagement efforts to beshared across teams. Similar coordinationtakes place with the urban design team,

when new developments make contributionsto public realm improvements.

In its urban forest strategy, the City ofMelbourne has committed to ensuring thatfuture planting and management decisionswill result in a dramatic increase of thediversity of the urban forest with no morethan 5% in any individual specie, 10% or anygenus and 20% in any family. The strategyexplains: When managing nancial assets,diversication is a basic rule for reducing risk.The same principle applies to urban forests,and tree managers around the world areinvestigating urban forest diversity. A greaterrange of species provides greater resilienceand long-term stability for the forest as awhole.

Extract from the City of Melbournes onlineurban forest map available athttp://melbourneurbanforestvisual.com.au



resources available for long-term treecare.

The content of the scheme valueassessment . While the benets broughtby trees and other green elements arenot always easy to quantify in monetaryterms, the HM Treasury Green Book 4 recognises the importance of greeninfrastructure and emphasises that,...material costs and benets that

cannot be valued in monetary termsshould clearly be taken into accountin the presentation of any appraisal orevaluation. A growing number of toolshave become available to assess the

replacement value of existing trees, aswell as estimate the benets associatedwith new trees.

The composition of the core andwider project team . Input from treespecialists within the core team fromthe earliest stages will enhance therobustness of the work on the projectbrief and facilitate the value assessmentrecommended above. It will also help

identify what level of site assessmentmight be required further down theline (soil test, tree safety audit, utilitiesmapping, etc), thus allowing for timelycommissioning and delivery. It will help

Case study 2South Shields Ocean Road

LocationSouth Tyneside, England

One of the keys to building a sustainablefuture for South Shields in the North East ofEngland is to strengthen the visitor and retaileconomy. Led by South Tyneside councilsregeneration department, with strong inputfrom the councils leadership team, the SouthShields 365 Town Centre Vision changed thelevel of ambition for the boroughs OceanRoad. This all-purpose urban A-road linedwith restaurants and guest accommodationruns from the retail heart of South Shieldsstown centre to South Tynesides sandy beachand parks a natural asset that attracts 1.7million visitors per year. The street, whichcarries an average daily trafc of 4,829vehicles and high pedestrian footfall, hadbeen scheduled for a simple refurbishment.It became a focal point for enhancing thedistinctiveness of the public realm and thecouncils chief executive argued that theinclusion of trees would be one of the bestways to achieve this. Working as part of amultidisciplinary and cross-departmentalproject team, the asset management,infrastructure and design staff explored howto incorporate an avenue of 78 long-lastingtrees in a shop front-lined street, deliveringhigh accessibility standards for widenedfootways and new on-street parking. Thedesign solution combined: A selection of hornbeams (Carpinus

betulus), a tree that can withstand windand saline content in the air. The cultivar

chosen, called Frans Fontaine, has acolumn-shaped crown, which ensures thatmaximum visibility to restaurant frontageswill be maintained. A trial planting of sixtrees was conducted in a nearby parkto determine with business owners thebest spacing for the trees. The councilslandscape staff visited the supplyingnursery soon after the project brief wasnalised to select the tree specimen thatwould be planted over two years later.

Use of below-ground engineered systemsto provide a non-compacted rootingenvironment and good load-bearingcapacity. The systems chosen were also

designed to address utility constraints: acrate system (StrataCell) was preferred forthe south side of the street where greaterlong-term access to utilities was desired

while a raft system (Permavoid SandwichConstruction) was used on the north side ofthe street. Demonstration days were heldwith the product suppliers and the councilengineering team to discuss the installationprocess and conrm that good access toutilities could be maintained where it wasneeded.

The project was funded through councilrevenue budget and local sustainabletransport funding and regeneration funds.Phase one was completed in April 2014 andphase two is expected to be completed inSeptember 2015.

Ocean Road newly completed in March 2014;choice of trees with column-shaped crownsmaintains good visibility to shop fronts.Image: South Tyneside Council

4The Green Book:

appraisal and evaluationin central government .HM Treasury, April 2014update. Found at:www.gov.uk/ government/ publications/the-green-book-appraisal-and-evaluation-in-central-governent


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identify key consultees who shouldbe involved in order to pre-empt anypotential conicts (eg engagement withCCTV managers).

1.1.3Setting the funding strategy on the righttrackEstablishing a robust strategy for fundingthe successful integration of trees in

projects relies on two tenets: Ensuring that the rst ve years ofpost-planting care, essential to enablea newly planted tree to successfullyreach independence in the landscape(as per BS 8545:2014 5 , paragraph 11.2),are budgeted for as part of the capitalinvestment sums.

Taking a partnership approach todesigning a funding strategy. Whilededicated tree budgets are often verylimited, the multiple benets trees can

deliver if well articulated in the valueassessment or project brief and fullyrealised through the project design can justify access to funding andresources ranging far outside the greensector. An overview of possible leads topursue is provided below.

Funding and resources within thehighway teams reach Sources available to highway/ roads teams across Britain typicallyinclude maintenance fund allocationsfrom central government as well ascomplementary centralised funding forsafety improvements and alternativetransport development.

Highway/roads maintenance fundingcan be allocated from capital or revenuesources: Capital sources will cover scheduled

structural renewal of highway assets.This is one of the most effective waysto plan and deliver an incremental

increase of tree planting sites. Highwaymaintenance funds might be able tocover the full planting costs. If not,a recognised alternative is for thehighway fund to cover the excavationof the planting hole and surfacing upto the tree opening, while the greenasset team nds complementaryresources for post-planting care aswell as soil, plant and tree openingsurfacing materials and installation. Thiscost-splitting approach requires goodcoordination between the highwayand arboriculture teams. Advancenotice of the structural renewal workschedule needs to be given to the treeofcer, allowing for match funding

(such as developer contributions) andprocurement of works to be arranged ina timely manner.

Revenue sources cover the repair ofworn or damaged roads and facilities,either short-term patching or apermanent replacement. In additionto maintenance of the road surfaceitself, it also includes the cost oflighting, footway repair and cyclical

maintenance of verges, which shouldinclude the safety inspection andpruning of street assets such as trees.

Complementary centralised transportfunds are subject to rapid changes andare structured differently across Britain.These funds often allow the nancingof new planting, including materialsand installation costs. However, in mostinstances, the budget allocated underthis type of grant funding has to be

spent within the project timeframe. Iftrees are planted in the last year of aproject, this leaves no resources for post-planting care, which must be coveredby other means. Current examples ofcomplementary centralised transportfunds for England include: Integrated transport block funding .

This funding covers all expenditureon new infrastructure such asimprovements at bus interchangesand rail stations, local safety schemes,pedestrian crossings, footways,trafc management, route and

junction improvements, and cyclefacilities. Given the role trees canplay in facilitating trafc calming andenhancing walking and cycling as wellas improving junction legibility (seeparagraph 2.2), integrated transportblock funding is particularly well suitedto providing capital funding for newplanting.

Local Sustainable Transport Fund(LSTF) . The LSTF is a 600 million

DfT fund running until March 2015. Theaim is to support the local economyand reduce carbon emissions throughpromoting greater use of sustainableand low carbon travel choices. Thefund will continue in 2015/16 throughthe Local Growth Fund (100m capital)and via a bidding competition directlymanaged by the Department forTransport (78.5m revenue).

Cycle Safety Fund (CSF) . The CSFis a 20 million DfT one-off grantscheme launched in 2013 and coveringnancial years 2012/13 and 2013/14. Ithas provided funding for over 80 localprojects that are improving routes and

junctions to enhance both cyclist safety

5British Standard 8545:

2014, Trees: fromnursery to independencein the landscape .Recommendations.London: BSI



and the perception of safety for cyclists,which can be a real barrier to travel.As highlighted in paragraph 2.2.3, anddemonstrated in several examplesin this guide, trees can provide aneffective asset under this agenda.

Through the planning process, highwayor roads authorities can secure paymentsfrom new developments to create or

improve existing highways. These arecovered below together with mechanismsavailable to ensure new developmentsalso include trees in car parks and othernon-adopted hard landscapes.

Funding and resources within the planning teams reachEnglish, Scottish and Welsh legislationall contain provisions to allow localplanning authorities and highway/roadsauthorities to secure payments from

new developments to create or improveexisting highway infrastructure andensure that, where appropriate, treesare incorporated in newly developed orrefurbished hard landscapes. In England,this includes: Direct provision on new developments .

The most effective mechanism availableto planning authorities to secure treesin streets and other public areas is torequire planting to be carried out aspart of the landscape design schemeassociated with new development.Local authorities have a duty, underSection 197 of the 1990 Planning Act,to ensure the preservation or plantingof trees wherever appropriate whengranting planning permission. Thiswould generally be practised throughthe use of planning conditions andTree Preservation Orders. If a newdevelopment incorporates new roads orpublic spaces, including car parks, thereis a very signicant opportunity tointegrate new tree planting with other

elements, such as services, lighting,carriageways, surface treatments andadjacent structures. A robust landscapedesign scheme should ensure thatall these elements are harmonisedand trees selected to meet long-termobjectives (see Sections 2 and 3 of thisguide). The use of planning conditionsshould also ensure that the quality ofmaterials, planting and aftercare meetacceptable standards, as recommendedin this guide. It is vital in these cases toensure that adopting bodies, such as ahighway authority, are fully consultedon any planting proposals and arecommitted to the ongoing managementresponsibilities.

Section 278 Agreements . A Section 278(S278) Agreement (of the HighwaysAct 1980) is an agreement betweenthe local planning authority and adeveloper which describes proposedmodications to the existing highwaynetwork to facilitate or service aproposed development (ie typicallythe scope of any off-site works thatare required to mitigate the impact

of the development on the existingroad network). The S278 Agreementprovides a legal basis for theresponsibilities (nancial and otherwise)of parties involved in constructingworks on the public highway, typicallyincluding the agreed highway worksdesign, payments associated withthe works and possible claims, landprovision and dedication.

Section 106 Agreements . Section106 (S106) of the Town and Country

Planning Act 1990 is used tosecure nancial contributions froma developer, for example to fundimprovements to the highway nearto the development site. This mightinclude tree planting or match fundingfor post-planting care as a complementto a central government capitalinvestment package. Coordinationbetween the local planning authoritystree and planning staff should ensurethat appropriate policy and fundmanagement measures are in place sothat S106 money collected specicallyas mitigation for tree losses or fortreescape enhancements is ring fencedand can be only spent on tree planting.

Community Infrastructure Levy (CIL) .CIL will increasingly replace the useof S106 Agreements as a source offunding for infrastructure related tonew developments. Local planningauthorities produce a CIL chargingschedule, which must be approvedby independent examination prior

to adoption. Local authorities mustinclude provision for tree plantingand associated maintenance (oran appropriate umbrella category,such as highway or street landscapeimprovements or green infrastructureprovision) within a Regulation 123List (from the CIL Regulations 2010).Once this has been adopted, alldevelopment subject to CIL payments,which may vary both between andwithin authority areas, will contributeaccording to locally xed tariffs.Section 106 contributions can thenno longer be sought or applied forinfrastructure included in the 123 List.The receiving authority must publish



annual reports indicating how themonies received have been spent.Some of the CIL receipts may also bepassed on to parish or town councilsor neighbourhood forums for localinfrastructure provision, which couldinclude tree planting and maintenance.

Funding and resources within thearboriculture teams reach

Its own tree budget . There might beopportunities to optimise resourceallocation between maintenance andplanting and free up some resourcesfor planting (see paragraph 3.1.2 of thisguide). Long-term strategic planning isrequired to realise such opportunities.

Community sponsorship scheme .Fundraising for popular local schemesthrough street parties and similarevents not only helps with the budget,it also builds up strong community

support and commitment for post-planting aftercare. In Bristol, oneof the street parties held in 2012 aspart of TreeBristol, the local planningauthoritys community engagementprogramme around trees, raised 3000for trees in the adopted highway.In Leeds, the in-kind contributionprovided by the local shopping centrein watering the newly planted plane treein Dortmund Square proved essential tothe survival of the tree during the 2013spring drought (see Case study 3, pXX).

One-off national/local tree planting fund . From time to time, national orlocal governments issue one-off treeplanting campaigns associated witha grant programme. Often focusedon achieving target numbers, theseprogrammes typically do not provideresources for post-planting care or foraddressing the more challenging hardlandscapes situation.

Compensation claims resulting fromdamage to or loss of council trees . A

case study in Trees in the Townscape(p67) provides a good example of how,in the context of planned works byWessex Water, Bristol City Council usedthe evaluation tool CAVAT 6 to retainmature trees and obtain monetarycompensation for replacement plantingwhere tree retention was not possible.Like Bristol City Council, the LondonBorough of Islington has embeddedinto its tree policy the principle ofvaluation and compensatory claimwhen loss or reduction of counciltree value occurs: The council willseek compensation from any externalorganisation responsible for signicantdamage to or removal of any council

owned tree(s) to the value as calculatedby CAVAT. For 2013-14, the LondonBorough of Islington estimates incomebrought from compensation claims tobe in excess of 45,000.

Funding and resources accessiblethrough other partnerships Partnerships with other teams withinthe local authority, with other public

bodies, third sector organisations,utility companies and other privateorganisations also offer signicantopportunities to nd resources for treesin hard landscapes. These may include: Regeneration funding , through

partnerships with town centreassociations and Business ImprovementDistricts as well as a local authoritysregeneration team.

Health and wellbeing funding , throughengagement with the local clinical

commissioning group and third sectororganisations. Housing monies , through engagement

with third sector organisations eligibleto receive funds from responsibleproviders for greening housing estates.

Landll tax credits funding , throughpartnership with local voluntaryorganisations.

In-kind contributions to conductconsultations, assist with planting andpost-planting care through partnershipswith local voluntary organisations, asachieved in Bristol (see Case study 13,pXX).

Partnership delivery with otherinfrastructure providers . This mightinclude water companies, wheretrees are integrated to local drainagesolutions, as demonstrated in theCounters Creek example (see Casestudy 27, pXX). It is also not uncommonfor energy companies and theiralliances to fund tree planting ascompensation for tree removal.

For updates and other examples,including funding sources available inScotland and Wales, please visit theTDAG website atwww.tdag.org.uk/trees in hardlandscapes/funding for trees

1.2Design: multi-discipline input andholistic above/below-ground response

1.2.1Integrating trees into the site assessmentprocessFor highway schemes, a quality audit isa process whereby a series of discrete

6The Capital AssetValue Amenity Tree(CAVAT) method forevaluating trees takesinto consideration bothreplacement costs andcommunity value. Moreinformation can befound at:

www.ltoa.org.uk/ resources/cavat



evaluations of design conditions and howthe space operates are collected andgiven due consideration within the designprocess 7. Other development projectsequally require such an evaluation andtrees are among the features that shouldbe included in such assessments. Thismay include: An assessment of the safe and useful

life expectancy of existing trees

and their potential to be compatiblewith and of benet to the futuredevelopment and use of the site, asper the tree survey recommendationsset out in BS 5837:2012 8 . This would

consider species, location, current size,conditions of existing trees and theirultimate potential size. It would alsoassess the contribution of existing treesto the streetscape or overall quality ofthe site, and any potential conicts ornuisance trees might cause.

Wider context analysis of the treescape:types of trees in private properties, inadjacent streets, etc (see section 4.2

of this guide on the importance of treediversity).

Some of the criteria applied for this initialtree survey should be kept in ongoing

7Department of Transport(November 2011) Trafc

Advisory Leaet TAL5/11: Quality audit Inthe street design

process . Found at:www.gov.uk/

government/ publications/quality-audit

Case study 4Wirral Waters Green Streets project

LocationBirkenhead, England

Over the next 20 years, Peel Groups WirralWaters regeneration scheme is expectedto bring to Birkenheads derelict docklandsabout 420,000 square feet of new ofcespace and 13,000 new residential unitsalongside leisure and retail facilities. ByApril 2014, in advance of the scheme, over600 trees across 8km had been planted instreets and green spaces within and aroundthe Wirral Water area with another 600due to be planted over the next two years.This ambitious scheme is part of MerseyForests Green Streets programme whichcombines extensive street tree plantingwith improvements to local parks to ensurethat the setting for what is expected to bethe largest regeneration scheme in the UKis as attractive as possible. The goal is tocreate green links between residential areasand places of employment and trainingso as to maximise the schemes economicdevelopment and health impacts. Deliveredin partnership with Wirral Council andBirkenhead Development Land Trust, theWirral Waters Green Streets project is alsodesigned to ensure that local people in theWirral Peninsula feel a sense of ownershipof the work that is happening in their area.Following consultation with local residents,the planting targets the main roads, includingroutes down to the Wirral Waters investmentarea, to Birkenhead, to the train station andto the Wirral Metropolitan College as well

as routes to and through parks and socialhousing landscapes. Funding sources tomeet the 1.46 million total cost are: The Local Sustainable Transport Fund

(LSTF) through Merseytravel and the

Department of Transport. The resultsof a door-to-door evaluation surveyconducted in the project area played a keyrole in allowing the Green Streets projectfor Wirral to access LSTF: 25% of localresidents suggested that Green Streetswould encourage them to cycle to workmore regularly and 15% said that theywould walk more.

The Forestry Commissions Setting theScene for Growth programme supportedby the Department of Business, Innovationand Skills (BIS). For Richard Mawdsley,development manager of Peel Group, thereis no doubt that the green infrastructureinvestment underway in the WirralPeninsula is critical to the future success ofthe Wirral Waters scheme: Occupiers wanta compelling place. Its more and moreimportant to get the place right and give itan identity a campus feel on the doorstepof a vibrant city. The green infrastructurewill be at the forefront of the marketing.

ForestClim, a European Interreg projecton the role of trees and climate changeadaptation.

The funding secured covers not only theplanting costs but also the consultation andengagement process with local residents, aswell as post-planting care for the rst ve years.Wirral Council will adopt the trees and takeover management from that point onwards.

Before and after implementation of the GreenStreets programme at the corner of Laird andBrassey Street in Birkenhead.Before image: McCoy WynneAfter image: The Mersey Forest

8British Standard 5837:

2012. Trees in relationto design, demolitionand construction .Recommendations.London: BSI



monitoring of the performance of thescheme. This might include measurementof the increase in tree size andimprovements to tree health (see 1.4.2).

Another essential dimension of the siteassessment process is associated withthe below-ground environment. Furtherdetails on this are in 1.2.2 below.

1.2.2Proactively designing the below-groundenvironmentUnderstanding the below-groundconditions is particularly important whendeciding if the inclusion of new trees isfeasible.

Understanding the below-ground conditionsis essential.Image: Pr. Kai Bong, University of Birmingham

For all projects, early liaison with utilitiesis an essential rst step in the feasibilityassessment process. This should enablethe project to: Compile utility asset data for the

project area. With water companies itis important to explicitly request waste,

surface water and clean water assetdata because records for each of thesetree elements are usually maintained inseparate databases.

Enquire about planned refurbishmentor upgrades, and opportunities for

joint-work scheduling, as was achievedalong Hornsgatan in Stockholm (seeCase study 25, pXX) and in Henley-on-Thames public car park (see Casestudy 6, pXX), or joint problem solving,as underway in Counters Creek (seeCase study 27, pXX).

Utility records often do not reectaccurately the layout and conditionsof the subsurface. As a result further

investigations will always be necessary toascertain the availability of below-groundspace for tree planting. The new PAS128: Specication for Underground UtilityDetection, Verication and Location ,to be released by the Institution ofCivil Engineers in the summer of 2014,differentiates between four differentquality levels of underground surveyranging from the collection of utility

records (quality level D) to exposing thepipes and cables using trial holes (qualitylevel A). Each quality level is associatedwith different vertical and horizontallocation accuracy levels. The detection ofburied utilities is commonly done usinggeophysical techniques (such as cableavoidance tools and single or multiplefrequency ground-penetrating radar) andthe most appropriate technique(s) needsto be chosen depending on the expectedpipe material, pipe size, depth and

ground. It may be necessary to selectmore than one technique to achieve thehighest detection quality level. Furtherguidance on utility surveys, includingpros and cons of different techniques, isavailable at no charge from the SurveyAssociation 9 .

In the context of planning applicationswhere trees are proposed, some localauthorities, such as the London Boroughof Southwark, are requiring survey proofthat trees can be planted as shownon plan before permission is granted.When using such survey information inthe context of planning application, it isimportant to understand the accuracylevel of the survey data to be provided.Investment in information at this stagecan provide signicant savings later inthe project.

Where new development orredevelopment occurs in conjunctionwith improvements to existing highways,

opportunities to introduce the use ofcommon utility service enclosures shouldbe explored. In urban inll locations,the planning team has a critical role inproactively identifying locations wheremultiple redevelopments could jointlysupport such shared infrastructure.In larger new developments, the useof shared ducting site-wide shouldbe a priority consideration. A holisticapproach to the design and positionof below-ground utility apparatus andabove-ground landscaping especiallytrees is key to success. It is mucheasier to move a pipe or cable when it isonly on paper than when it has alreadybeen installed. The lack of a joined-

9See: The Survey

Association. GuidanceNote The EssentialGuide to Utility Surveys ;and The Survey

Association. GuidanceNote Utility Survey

method of measurementIssue 2 . Both found at:www.tsa-uk.org.uk/?page_id=24



up approach to landscape (especiallytrees) and below-ground utility results insituations in which everyone loses: Trees might not be able to be planted

where they would strongly enhancedthe environment for those living orworking near it or moving through it, asdescribed in section 2 of this guide.

Conicts might easily arise if suitabletree choice and infrastructure design

measures, as detailed in 3.4, are nottaken, leading to the need for expensiveremedial work.

Opportunities to reduce the need for, orto downscale the size of, below-groundinfrastructure might be missed: treesare of particular relevance to assistwith the management of surface waterrunoffs and alleviate drainage networks(see 2.4 and 3.5).

Whether in the context of a private

development or a highway scheme,design of the below-ground tree-rootingenvironment will be a determining factorof tree health and of successful long-term co-existence between trees and allsurrounding infrastructure, including notonly utilities but also hard surfaces andabove-ground structure. Detailed adviceon this is provided in section 3.

1.2.3Securing early and substantial input froma tree specialistConsulting a tree specialist on treespecies selection and placement as wellas sizing and design of the below-groundrooting environment is essential, not onlywhen planting new trees, but also whenrefurbishing hard landscapes aroundexisting trees. In the latter situation, lackof engagement with a tree specialistoften results in missed opportunitiesto enhance the design of the rootingenvironment, and improve the longevityof both the tree and the surrounding

infrastructure.

Depending on circumstances and projectneeds, such a tree specialist might be: A project advisor or consultant with

adequate qualications and experiencein young tree establishment or remedialwork on tree roots and tree rootingenvironments.

The long-term tree manager/owner,such as the local authority tree ofcer.

The latter is particularly important asthey know the resource limitationsfor long-term maintenance. However,refurbishing around an existing highvalue tree or planting in most challenging

hard landscapes situations might requireexpert input from specialists in youngtree establishment or root environmentremedial work.

Involving the tree specialist(s) early inthe design process will help to identifypotential conicts between trees andinfrastructure, and allow the team to workout effective solutions collaboratively.

This can be greatly facilitated by: A willingness to give and take: it isimportant for the tree specialist(s)to take a whole urban forest view,accepting that this may mean theloss, at times, of some trees as long asadequate provision for replacements ismade (preferably using canopy coveror diameter at breast height as thepoint of reference see Trees in theTownscape Principle 3).

A readiness to consider proposed

specications that depart from localdesign standards and to take part inknowledge sharing sessions wheretechnical issues can be discussedin the context of real life examples.For example, Norwich city councilstree ofcer invited the crate system manufacturer he wanted to use in theSt Georges scheme (see Case study21, p XX ) to facilitate a thorough in-situdiscussion of the load spreading andinstallation issues that were of concernto his highway colleagues. The go-ahead for the project was agreed soonafterwards.

1.2.4Designing with maintenance andadoption in mindPost-planting care is important if longevityin the landscape is to be achieved. A fullyoung tree maintenance programme withbudgetary provision should be in place forall planting schemes. This maintenanceprogramme should be in place for at least

ve years and include not just wateringand re-staking but also formative pruning (see 1.4.1).

Beyond post-planting care, a tree should,for the most part, be healthy and self-sustaining. Future anticipated capacityfor maintenance (in terms of technicalskills, budget and time) should informdesign choices. Seeking feedback on theproposed design from the maintenanceteam is essential to help determinewhether the option being pursued ispractical. Important topics to exploreinclude: Ease of cleaning around the base of the

tree.



The maintenance record of thematerials proposed for the surfaceopening at the base of the tree (egaggregate, permeable pour-in rubber,tree grille/grate, etc), including cost,frequency and ease of repositioning,repair, rell or replacement.

Inclusion and maintenance of anirrigation and/or aeration system.

Inclusion and maintenance of a silt trap

and drainage outlet. Formative pruning and crown lifting . Provision for access to underground

utilities.

The designer must ensurethat maintenance is simpleand if not followed throughfor whatever reason, theconsequences will notcompromise the tree. Far

too many trees have diedbecause of bad designeg steel cages, metal tree

grilles.Howard Booth, Transport for London

1.2.5Capitalising on trees for communityconsultation and planning permissionWith many highway schemes therewill be a need for thorough publicconsultation and involvement.

Bristol city councils highway staff foundthat by working more closely with thegreen space teams arboriculturists,greater inclusion of tree planting inschemes often eased the consultationprocess.

In the minority of instances where treesraise concerns (see the Brislington Hillexample in Case study 13, pXX), theability to take community groups on a

tour of similar projects delivered jointlyby the highway and the arboricultureteam made a decisive impact.

For projects requiring planningpermission, a positive approach towardstrees can help facilitate the approvalprocess. Such an approach will bedemonstrated through: The proactive adoption of protective

measures towards existing on-site treesor adequate replacement measureswhere this is not possible (see Trees inthe Townscape principle 3 and Casestudies on pp23-24).

The inclusion of new trees providedwith sufcient space and sustainable

growing conditions. Articulating the value added by the

planting of new trees and the retentionof existing trees through the use of treevaluation methods, and using graphicsto help visualise the canopy coverenhancement.

1.3Implementation: joined-up work

sequence and site supervision

1.3.1Dening contracts, qualications androlesAfter a well-designed scheme witha competent specication has beenprepared, the next stage is to implementit.

For a public works scheme,implementation may be handled in a

variety of ways. A local authority mayhave in-house staff responsible formanaging the project and, in some cases,undertaking construction, or they may gothrough a tender process to award thecontract externally.

For private developments, contractsare usually awarded through a tenderprocess.

In all cases, responsibility for specicaspects needs to be well delineated, andthe delivery programme must clearlyidentify the order in which the work isto be undertaken. This is particularlyimportant where load-bearing systemsare integrated into the design of the root-growing environment (see 3.2).

Where existing trees are present, tendersand statements of work for constructionor maintenance around trees should beexplicit on qualication levels: Contractors undertaking work on trees

should provide evidence of adequateinsurance and an arboriculturequalication accredited by the relevantprofessional body.

Contractors conducting specialisedinstallations of load-bearing systemsfor tree planting (such as crate systems see 3.2.2) should have access toadequate engineering expertise.

Contractors working near trees (whichis almost anyone conducting workon streets) should also demonstrateadequate environmental awareness (egISO 9001 certication).

Tender documentation, which includescontracts as well as references to


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Case study 6Joint working with Waitrose toretrot trees in public car park

LocationHenley-on-Thames, England

When the time came to refurbish a SouthOxfordshire council-owned car park locatedadjacent to a large Waitrose in Henley-on-Thames, the council and the retailer decidedto work together. Waitrose customers wereextensive users of the public car park and itneeded resurfacing due to a combination ofnormal wear and tear, drainage issues androot damage caused by mature plane treesthat predated the car parks creation. Theoriginal planting scheme comprised some 14trees, predominantly rowans (Sorbus spp.),that had been planted when the car park wasestablished. Due to soil compaction and lackof adequate rooting environment, the rowantrees were either missing, dead or dying.

Having been notied by the councilsproperty management team that the carpark was to be resurfaced, the councilsarboricultural lead approached Waitroseto seek their support in integrating a treereplacement strategy into the project. Afew years earlier the council had secureda nancial bond for tree works in relationto another Waitrose site and both partiesagreed that the Henley car park provided agood opportunity to use this fund.

The agreed strategy relied on the use ofpermeable asphalt over the root zone of theexisting mature planes and a load-bearingcrate system (SylvaCell) to plant four newplane trees to replace the rowans. The designof the rooting environment for the newplanes also featured aeration and irrigationpipes connected to vents integrated intothe new surfacing. The choice of largecanopy trees combined with good designof the below-ground environment wouldensure that, although only four trees were

being replanted, the impact, in terms ofshading, aesthetics and longevity, would bemuch greater while parking space would bemaximised.

The rst phase of the scheme consistedof the installation of two of the fourreplacement trees plus the laying of thepermeable asphalt near those existingmature plane trees that were to be retained.This went ahead as planned in combinationwith the car park resurfacing work, allowingsignicant cost savings to be made sincethe tree work could be conducted withequipment and ground teams already on site.However, the cross-departmentalcollaboration that had enabled the successfuldelivery of phase one was not sustained.Drainage upgrade works that affected thearea where phase two was expected totake place went ahead without prior noticehaving been given to the arboricultural team.The opportunity to use the tree-rootingenvironment to assist with surface waterattenuation or to simply share costs onmachinery use and ground workers was lost.When priced in isolation, the planting of thetwo remaining replacement trees provedto be twice as expensive as phase one andcould not be accommodated within theavailable budget.

Top left: Surface damage around mature planeprior to resurfacing. Image: Martin Gammie

Right: New replacement tree, one year afterplanting. Image: Martin Gammie

Bottom left: Surrounds of mature plane post-reinstatement, featuring permeable asphalt.Image: Martin Gammie



1.3.3On-site presence and supervisionSimple things can make a big differenceto effective implementation and to theteam condence. For example: The presence of the tree specialist on

site can help identify tree protectionzones for existing trees and alsocontribute to the resolution of day-to-day issues for both existing and new

tree planting. See Case study 13 on howBristol appointed a dedicated tree staffto a large capital improvement scheme.

It is essential that where/when lessfamiliar techniques are used to enhancethe tree rooting environment (throughthe use, for example, of one of theload-bearing planting systems), theconstruction manager and the treespecialist build a shared understandingof the construction details, worksequence and quality of workmanship

required. In Lyon in France andStockholm in Sweden, two cities whereskeleton soils have been extensivelyused, training sessions for constructionmanagers and/or site controllers areregularly held to continuously improvesustainable integrated infrastructuredelivery capacity.

Alliances are built if, as excavations takeplace and reveal an opportunity fortree planting (eg if utility apparatus isnot where expected), the constructionmanager takes note and puts anoffer out to his landscape design orarboriculture colleagues to t in anadditional tree.

1.4Maintenance and monitoring

1.4.1Post-installation maintenance is keyAs highlighted in Annex G of BS 8545:2014, provision of ve years of post-planting care is essential. This should at

least involve: Watering. For four to ve months aftertransplanting, a tree exclusively relieson the water found in the soil within theroot ball . Frequency and regularity ofirrigation at this early stage is essential.The period over which irrigation isrequired is likely to be at least two fullgrowing seasons.

Checking and adjustments of treestakes and ties or below-ground rootanchor systems.

Removal of support and protectivedevices when they are no longerneeded.

Checking that grates, grilles andother furniture do not damage or

compromise the tree, taking remedialaction where appropriate.

Replenishing mulch at the base of thetree.

Formative pruning . Nursery pruningis an integral part of the productionprocess of trees but the branchstructure created is usually temporary.Trees without formative pruning aremore prone to develop defects. These

in turn can shorten the tree life and putpeople and property at risk. Remedialpruning once trees have grown moremature is much more expensive.Formative pruning is therefore anessential part of the post-plantingmanagement and maintenance oftransplanted trees.

1.4.2Monitoring and continuous learningA formal assessment of young tree health

and development should be carried outannually, as recommended in BS 8545:2014, paragraph 11.5.1. Monitoring shouldalso include qualitative dimensions, asrecommended in LTN1/08 paragraph 4.2.

Local authorities may have obligationsto monitor the performance of someschemes. However, other competingobligations, such as scheme delivery orresource restrictions, may compromisethe achievement of effective monitoring.In larger schemes, it might not befeasible to nd the time and resources tomonitor all trees but it is recommendedthat at least a representative sample ismonitored. Indicators might include treecover and tree health.

Monitoring can empower the projectteam through: Learning about what works well and

what does not. Enhanced understanding of the

contractors performance.

Increased opportunities to undertakeadjustments before failure requiringsignicant expenditure occurs.

Evidence to build the case for futureinvestment in good practice.

1.4.3Innovative approaches to contractsMany different types of contracts areavailable to local authorities and otherorganisations to procure maintenanceand works.

It is essential to review contractualarrangements very regularly to ensurethe best procurement route is securedfor the services to be delivered.



Case study 7Research and development in theGreater Lyon Authority

LocationLyon, France

A few years ago, excavation of LyonsBellecour Square revealed a set of mid-19th century underpinned footways andporous irrigation pipes that made use ofgravity to take in surface water runoff. Thediscovery revealed that over 150 years agothe knowledge existed to build sophisticatedgreen-grey-blue infrastructure solutionswhich are only being rediscovered today.This was one of the triggers that led theGreater Lyon Authoritys arboriculture teamto make research and learning an explicitobjective of project delivery. As a result,inclusion of an element of research anddevelopment in each major highway projectis one of the key commitments written in thetree charter agreed by the Greater LyonAuthority (GLA) and 65 local authoritiesand other local partners. This innovationprinciple and continuous improvementapproach is focused primarily on threethemes: soil, water management and climatechange. The R&D work associated with theGaribaldi project (see Case study 15, pXX)explores the last two themes.

As part of the Garibaldi Street refurbishment,an old underpass that had allowed cars toavoid ground level intersections is beingconverted to a rainwater collection cistern.Water from the cistern will be used for,among other things, the irrigation of the newplanting areas. Trees will be integrated intothe new streetscape created by the project.Beyond the rst three growing seasons,

irrigation will only take place during droughtperiods in the growing season. The objectiveis not only to ensure the vegetation survives,but also to maintain its ability to cool localtemperature through evapotranspiration.One of the strategies trees use to managewater stress is to close the stomata ontheir leaves so as to limit water loss dueto transpiration. Maintaining good waterprovision enables the tree to keep its stomataopen for gas exchange and perspiration.Censors to be installed within and around thenewly planted trees and vegetation strips,as well as around existing trees, will allowthe team to quantify the cooling effect ofvegetation at different stages of maturityand under different irrigation regimes.Censors are also being installed further downthe street, where the refurbishment is to becompleted in later phases, to provide controldata. The cost of the censors installed arecovered as part of the capital budget forthe Garibaldi Street refurbishment whiledata analysis is being nanced through thearboriculture teams own budget.

Garibaldi Street, after phase one refurbishment.Image: Frdric Sgur

For further images see p XX and p XX



Consideration should be given to: The impact of contractual choices on

the quality of the work or servicesbeing procured and the diversity of alocal pool of skilled contractors. TheGreater Lyon Authority has embeddedin its tree charter (see Case study30, pXX) the principle of developingrelationships with local nurseries soas to build a robust and traceable

supply chain for its ambitious treeplanting programme. It also requiresthe use of multiple local contractors forarboricultural work in order to build uplocal long-term capacity to deliver veryhigh quality schemes economically.

The sharing of contracts across councildepartments. Savings can be made inthe delivery of routine maintenanceactivities through sharing contractsfor services used by both highwaysand green space teams. The unit rates

a client can secure will often varyaccording to the volume purchased.For example, within a local authority,a highway department may manageto secure a much lower car haulagerate than their green space colleagues.In Bristol city council, it is thereforecommon practice for the two teams toshare contracts to procure services they

both use. According to Russell Horsey,former arboricultural manager at Bristolcity council, There are two possibleattitudes: I get you a budget to manageour highway trees and I dont want tohear from you or lets work togetherand use each others contracts to getbetter value.

The sharing of contracts across localcouncils. Some types of arboricultural

work, such as planting and caringfor young trees in hard landscapes,requires skilled labour. However,procuring such services on a singlecouncil basis might be too onerous oruncertain (in terms of the volume ofworks) to be practical. Yet resortingto the default contractor used formaintenance might not deliver thequality of services required. Procuringsuch specialised services on a cross-council scale offers a good alternative,

allowing the spreading of the overallcost of the tendering process. TheLondon Borough of Islington and otherneighbouring councils are currentlyexploring this route for procuring treeplanting services. The City of London isusing the London Borough of Islingtonscontracts for tree works.

Whiteladies Road after completion of the GBBN scheme.Image: City Design Group 2014, Bristol City Council



Demonstrate leadership Ensure that there are clear policies

for the protection, care and plantingof trees in the Local Plan (for localauthorities), Highway Management Plan

and/or other relevant corporate policydocuments.

Demand and enable strongcommitment to the implementation ofadopted tree policies at all levels of theorganisation through collaborative andcross-disciplinary working.

Integrate the right range of tree skillsand information (particularly on below-ground conditions) from the outset of

projects.Secure adequate resources Take a partnership approach to funding,

capitalising on the multiple benetsdesigning with trees can deliver.

Fund critical post-planting care fromthe capital investment budget.

Explore community involvement inaftercare where appropriate.

Look after implementation and aftercare Secure competent implementation

through a good specication and adelivery manager well briefed in oradvised on technical solutions for treesin hard landscapes.

Seek seamless integration of highwayand treeworks this will deliver bettervalue for money.

Explore innovative approaches to

contractual arrangements, maximisingopportunities for cross-department orcross-council sharing.

In Summary

Trees in Hard Landscapes28 Consultation draft



British Standard 8545: 2014.Trees: from nursery to independencein the landscape. Recommendations .London: BSI.

British Standard 5837: 2012.Trees in relation to design, demolitionand construction. Recommendations .London: BSI.

References

Non-technicalpublicationsand resources

Professionalpublicationsand resources

Scholarlypublications

Trees in Hard Landscapes 29Consultation draft



Designingwith Trees

Consultation draft


33/130Trees in Hard Landscapes 31Consultation draft Trees in Hard Landscapes 31

2.1 Effective use of space and sense 00of place

2.1.1 Making space for trees: a shared 00responsibility

2.1.2 Adapting tree choices to local conditions 002.1.3 Tree and local distinctiveness 002.1.4 Tree for immediate (and lasting) impact 002.1.5 Tree strategies for year-round impact 00

2.2 Safe movement for all 002.2.1 Trees and urban road safety 002.2.2 Trees for trafc calming 002.2.3 Trees for inclusive walking and cycling 00

2.3 Unobstructed splays 002.3.1 Trees and junction visibility splays 002.3.2 Trees, commercial signs and shop 00

window visibility2.3.3 Trees, lighting and CCTV 00

2.4 Water sensitive design 00

2.5 Safety, health and comfort 002.5.1 Trees and public safety 002.5.2 Trees and peoples health 002.5.3 Trees and air quality 002.5.4 Trees, temperature and wind control 002.5.5 Trees and wildlife health 00

2.6 Surface treatment, cleaning and 00de-icing

2.6.1 Leaf fall and droppings 002.6.2 Surface treatment and cleaning options 002.6.3 De-icing salt 00 Section Summary and References 00

Consultation draft



Designing with TreesUsing trees as positive assetsPrinciple 6 of Trees in the Townscape: A Guide for DecisionMakers argues that the inclusion or retention of trees isbest approached as a means to an end rather than as anend in itself .

The guide further advises: When considering the aspirationsfor a neighbourhood, street or single site, the question

should always be asked: how can trees support the visionfor this place? How can trees provide solutions to the issuesidentied? [...] Designing with trees is a matter of trying toachieve a balance between securing the maximum requiredbenets with the least possible disadvantages .

The list of benets urban trees can deliver to their immediatesurroundings is rich: quality of place, economic potential,health and wellbeing, nature conservation and habitatconnectivity, local food and community links, trafc calming,surface water management, air pollution control, coolingand sheltering, noise abatement and more (see Trees in theTownscape , pp40-45).

Fully realising any of these benets requires a concertedstrategy that both exploits enabling factors and devises

solutions to potential conicts. This section explores theabove-ground components of such a strategy.



Retail




Attractive retailenvironment alongthe high street

BoulevardBUSLANE

Shadedsquare

Deliveries

Retail

Town Hall

Mixed use

L o a d i n

g

Retail and Ofces

Parking

Parking

Parking

Successful take-up

of alternativetransport modes

Park and Ridecarpark

Water-sensitiveurban design

Enhancingurbanbiodiversity

Trafc Calming

PedestriansCyclists

Downpipe directing roofrunoff to tree rootingenvironment

Surface water runoffdirected to tree rootingenvironment

Not to scale for illustrativepurposes only



2.1Effective use of space and sense of place

2.1.1Making space for trees: a sharedresponsibilityPrinciple 4 of Trees in the Townscape:

A Guide for Decision Makers advocatescreating places where trees can thriveand deliver their full range of benets

without causing harmful nuisance ( Treesin the Townscape , pp30-33).

Exploring the oft-cited adage rightplace, right tree, the guide emphasises

that good tree design involves bothadapting the selection of the tree to thecontext and ensuring the design of thesurrounding infrastructure allows fortrees to thrive. The guide argues that thelatter ought to be considered rst wherepossible because it largely predeterminesthe very possibility of having trees in theurban landscape.

Faced with an agreed design objective toplant trees but competing demands forspace, design teams sometimes resort toplanting trees in above- or below-groundcontainers with insufcient growing

Case study 8Lyon and London reclaim roadspace for trees

LocationLyon, France. London, England

In Lyon, the second largest metropolitanarea in France, high quality public space isa strategic priority to secure and sustaineconomic growth. Local municipalities havetherefore granted the Greater Lyon Authority(GLA) responsibility for highway and civicspace design. When residents startedchaining themselves to trees that were beingremoved to make way for urban motorways,a dramatic shift in both transport planningand public tree management ensued.Between 1990 and 2014, the GLA plantedover 50,000 new trees and replaced about18,000 existing older trees, all in publichard landscapes. This, explains FrdricSgur, the GLA arboricultural manager, wasmade possible by reclaiming space overvehicles: Our tree and alternative transportdevelopment strategies go hand in hand:the latter frees up space for the former, theformer creates the attractive environmentneeded for the latter. There is no other waywe could have succeeded .

In the UK, the City of London has pursuedsimilar trade-offs, driven by heightenedconcern for security. Reducing vulnerabilityto terrorist attacks required limiting vehiculartrafc. This, however, could not come at thecost of reduced accessibility for the UKsnance and insurance hub. The responsewas the ring of steel, the security andsurveillance cordon surrounding the City of

London, which allowed the City to reclaimapproximately six football pitches worth

of roadways for public space and extensivetree planting in what is probably the densestand most constrained urban centre in thecountry.

Below right: Tree and alternative transportstrategies go hand in hand in Lyon.Image: Anne Jaluzot

Bottom left and right: Before and afterreclaiming road space at West Smitheld in theCity of London.Image: City of London


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spacing. Where issues with access tolight arise from trees planted too closeto building frontages, reducing plantingdensity might be an appropriateresponse, along with careful choice oftree and leaf size.

Species : this choice will determineshape, colour, density of foliage, etc.However, aesthetic considerationsshould not override other important

criteria for long-term success whenselecting tree species (see section 4).

2.1.4Trees for immediate (and lasting) impactSecuring immediate impact is often aconcern on high visibility civic squaresor commercial projects. Addressing thislegitimate concern commonly leads to: Planting trees at a higher density to

compensate for the smaller size of thetree. This strategy, which is derived

from forest management practices, canoffer some advantages: trees competeand can attain height more quicklywhile protecting each other duringvulnerable early years. Regular thinningof the weakest trees to make space forthe strongest specimens is essential forsuch a strategy to yield good results.In urban settings such an approachmight be applicable for trees plantedin soft landscape areas, verges or largecivic spaces with open ground planting.Failure to undertake selective felling asthe trees mature can result in poor treegrowth, increased maintenance costsand nuisance for neighbours (see theSane embankment pictured on pXX).This planting strategy is unlikely to besuitable for trees in hard landscapeswhere competition for space is erce,high investment in providing goodquality rooting environment or loadbearing is needed, and/or progressivefelling of young trees to achieveadequate mature spacing is impractical

and likely to generate public outcry.

impact, in the townscape. A positivedesign aspiration is to aim for theinclusion of larger trees, even if thismeans planting a smaller number.

Arrangement of planting : thepossibilities are endless and will dependon the particular site and the designobjectives. Choices should reect thelocal setting: linear planting will supporta strong urban frontage while individual

accent planting might be more suitedto market town settings and intimatepublic squares. Where widths allow,double rows of planting is possible.

Spacing : unless otherwise agreedand supported through a long-termmanagement programme (see 2.1.4),trees should be planted at their nal

On the River Sane embankment in Lyon,France, removing half the number of treesyields the same townscape impact but muchimproved access to light for residents.

Images: Frdric Sgur

BS 3936 Part 1: Nursery stock Further guidance/description,specication for trees and shrubs as provided by Barcham Trees

Standardised Corresponding tree Description in Anticipated treeclassication girth size common language height when plantedLight Standard (LS) 6-8cmStandard (S) 8-10cm 7-9ft (2.1-2.7m)Select Standard (SS) 10-12cm Large tree 9-11ft (2.7-3.3m)Heavy Standard (HS) 12-14cm Instant impact tree 11-13ft (3.3m-4.0m)Extra Heavy 14-16cm Specimen tree 13-15ft (4.0m-4.6m)Standard (EHS)

Advanced Heavy 16-18cm 15-17ft (4.6m-5.2m)Standard (AHS)Semi-mature 18-20cm+ Mature and semi-mature 17-19ft (5.2m-5.8m) trees



Exclusively planting larger diameter orsemi-mature trees. Older, semi-maturetrees (as described in the table belowon tree sizes) are less adaptive thantheir younger, smaller counterparts.When planting semi-mature specimen,higher quality of tree stock, treehandling and post-planting care arerequired to achieve success. This needsto be reected in the budget and

procurement process.

Alternative strategies to secure instantimpact include:

Securing good growing conditions forthe trees as this will promote fastergrowth. The growth rates observed inStockholm among new trees plantedwith excellent soil aeration provides astriking example (see Case study 19,pXX).

Considering the use of multi-stem trees(if compatible with the design intent)as these could be planted alongside

smaller diameter trees until they havegrown sufciently. Combining species that have different

growth rates. Preserving and integrating existing

trees into the scheme while combiningtrees of different diameters in newplanting.

2.1.5Tree strategies for year-round impactIncreasing the diversity of the species

used not only supports better resistanceto pests and diseases and improvesresilience to climate change, it alsohelps ensure that the trees make avaluable contribution to the townscapethroughout the seasons. Consider: Incorporating evergreens. Where

uniformity is not required to maintainlocal character, the inclusion of someconifers or other types of evergreentrees can positively contribute to thelandscape. They need to be positionedcarefully as they will provide shadethroughout the year.

Mixing in species that shed their leaveslater in the season. As pictured belowin the new neighbourhood being

Multi-stem trees marking the entrance of thenew cinema created in converted shipyardsin Lyons Vaise neighbourhood (France).Image: Anne Jaluzot

In the former Sathonay military base being redeveloped as an urban extension near Lyon,new streets have been planted with oaks ( Quercus frainetto ), alders ( Alnus glutinosa ) andwillows ( Salix alba ). The fast growing willows will be removed within 20 to 25 years and thealders within 40 to 60 years. By then, the oaks will have grown to buffer these losses.Images: Anne Jaluzot (winter) and Frdric Sgur (summer)



Below left and right: The Greater LyonAuthority shifts new planting to the middleof the street to support its alter

Documents

Trees in Hard Landscapes Consultation Draft 28 May 2014