PART B

A practical guide to

managing Box woodlands

and trees in the countryside

The natural

and cultural

heritage of

Box woodlands

and trees in

the Chilterns

PART B

A practical guide to

managing Box woodlands

and trees in the countryside

An Area of Outstanding Natural Beauty

The natural and cultural

heritage of Box woodlands

and trees in the Chilterns

Published by the Chilterns Conservation Board

Grant-aided by the Heritage Lottery Fund

Written by Sarah Wright, Chilterns Box Woodland Project Officer

PART B has drawn on the assistance of volunteers, woodland owners and other supporters.Thanks to:

Boxmoor Trust, Chiltern Society, European Boxwood and Topiary Society, Forestry Commission, Millennium Seed Bank Partnership Kew, National Trust, Natural England, Royal Horticultural Society, Society of Wood Engravers, Wormsley Estate.

Lynn Batdorf, Colin Bradley, Clare Butler, Dorothy Cartwright, Huw Crompton, Chris Daunt, Christine Davis, Beatrice Henricot, Peter Jones, Stuart King, Keith Kirby, Andy McVeigh, Neil Melleney, Glyn Miller, Heather Barrett-Mold, Sandra Parkinson, John and Ben Pepper, Edward Raker, Sean Reid, John Trimmer.

PART B

A practical guide to managing Box

woodlands and trees in the countryside

Chilterns BoxWoodland Project

Contents

Managing Box woodlands and trees in the countryside

B.1 Introduction to the Chilterns Box Woodland Project and this publication

B.2 Managing Box woodland and trees for the future

B.3 Management challenges in the Chilterns

B.4 Managing Box trees to be healthy specimens and recognising signs of stress

B.5 Box management calendar

B.6 Managing for climate change

B.7 Growing Buxus sempervirens – propagation

B.7.1 Collecting and growing from seeds

B.7.1.1 Case study: Collecting Box seeds in the Chilterns for the

Millennium Seed Bank, Wakehurst

B.7.2 Collecting and growing from cuttings

B.7.2.1 Case study: Collecting Box cuttings from Ellesborough and

Kimble Warrens SSSI

B.7.2.2 Case study: Growing Box cuttings in a nursery

B.7.3 Propagation by layering – 'air' and buried

B. 7.3.1 Case study: Layering Box at Wendover Woods

B.8 Planting Box in the countryside

B.8.1 Sourcing stock to plant

B.8.2 Selecting sites to plant Box

B.8.3 Case study: New Box plantation managed for game at the

Wormsley Estate

B.9 Treework for Box trees

B.10 Managing ancient and veteran Box trees

B.11 Managing established Box woodlands and Box scrub, including managing

for timber

B.11.1 Harvesting timber

B.11.1.1 Case study: Harvesting timber from a Box plantation in Norfolk

B.11.2 Case study: Coppicing in Wendover Woods

B.11.3 Managing Box along access routes

B.12 Managing pests, diseases and other problems, including biosecurity

recommendations

B.12.1 Case study: Tackling Box blight in the publicly accessible Wendover

Woods

B.12.2 Yellowing leaves

B.12.3 Copper brown leaves

B.12.4 Box blight

B.12.5 Rusts

B.12.6 Macrophoma leaf spot

B.12.7 Phytophthora

B.12.8 Nematodes

B.12.9 Box tree caterpillar

B.12.10 Psyllid moth

B.12.11 Animals affecting Box

B.12.12 Climbing plants – ivy, wild clematis

B.13 Credits to volunteers and others

B.14 Reference list and further reading

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B.1 Introduction to the Chilterns Box Woodland

Project and this publication

The Chilterns Box Woodland Project began in January 2013 following receipt by the Chilterns

Conservation Board of a grant from the Heritage Lottery Fund. Over a period of two and a

half years, the Chilterns Conservation Board gathered information about Box trees and

carried out simple trials of different practical management activities. The focus was upon

Box in a countryside setting, not Box in gardens and topiary.

This guidance brings together all that has been learnt through the Project and aims to

provide woodland managers and others with the key information they need to sustainably

manage Box trees and woodlands in the Chilterns countryside and possibly elsewhere.

Questions and uncertainties remain, but this publication is a step forward and starting point

for informed conservation and heightened appreciation of the natural and cultural heritage

of Box.

Alongside this guidance, the Project has worked with the Forestry Commission at the

publicly accessible Wendover Woods to give everyone the opportunity to explore a Box

woodland and see first-hand how it can be managed.

In addition to this guidance called Part B addressing practical management, Part A covers

the ecology, history and cultural uses of Box in the Chilterns.

Visit for further information and to download the most up-to-

date version of this publication.

www.chilternsaonb.org/box

Managing Box woodlands and trees in the countryside

This guidance draws on the knowledge and experiences of numerous people engaged through the Chilterns Box Woodland Project. Various site visits were carried out, as shown here at Shirburn Hill.

Page 1

B.2 Managing Box woodland and trees for the

future

Having fallen into widespread neglect and obscurity, Box trees and woodlands are in need of

attention. A degree of urgency is created by the growing challenges of pests and diseases,

such as Box blight, and climate change. Significant restorative work is needed in some

places in the Chilterns, whilst in other locations it is just a matter of integrating small tasks

for Box into existing management routines. A positive driver for management is the

opportunity to secure a sustainable source of UK-grown Box timber to supply a small but

interested market.

Fortunately, large Box woodlands and vigorous Box trees can currently be found in the

Chilterns and natural regeneration is evident in many places. Prime examples include the

ancient woodland near Great Kimble and a publicly accessible woodland near Wendover. The

woodland at Great Kimble is designated as part of the Chilterns Beechwoods Special Area of

Conservation in recognition of its international biodiversity significance. Shirburn Hill SSSI is

another key site which provides a useful example of Box scrub in a chalk grassland context

that is publicly accessible. These Box sites make the Chilterns a useful reference point for

anyone wishing to understand the ecology, history and management of Box. The Chilterns

Area of Outstanding Natural Beauty is also a place to see how Box contributes to creating a

distinctive and attractive landscape.

It is worthwhile to work and learn with the network

of people who have an interest in Box: woodland

owners, foresters and arborists, woodworkers,

musicians, artists, gardeners, researchers and the

public. The Chilterns Box Woodland Project has

strengthened the links between these interest

groups and made information easily accessible

online at www.chilternsaonb.org/box. From this

point, it is possible to make further progress and

ensure the natural and cultural heritage of Box in

the Chilterns remains alive.

Managing Box woodlands and trees in the countryside

Box timber is used to make and repair some instruments. Musicians, such as Katherine Spencer, are amongst a network of people wanting to secure a sustainable future for Box trees and woodlands in the Chilterns.

Page 2

B.3 Management challenges in the Chilterns

The Chilterns Box Woodland Project carried out surveys of Box woodland and trees across

the Chilterns and beyond, and also discussed current and historic management with

woodland owners and others. It was found that the majority of Box trees and woodlands

received little management attention. Various aspects were identified which presented

managers and others with challenges particular to Box.

This guidance and other resources available at www.chilternsaonb.org/box can help

woodland managers and others to tackle the following problems and achieve sustainable

management of Box:

` Lack of easily accessible information about managing Box in the countryside. No

established network of people knowledgeable about Box.

Pests and disease, such as Box blight, affecting living trees and timber.

Few people with practical skills and experience specific to Box. Limited number of

informed contractors. Concerns about mis-management.

Neglected Box, and the consequent challenge and time needed for restorative work to

trees and woodland. Illegal camping and accumulation of litter are associated

problems.

Negative or limited perceptions of Box that distract from positive management action,

e.g. it is just about topiary; it isn't a tree; it isn't a timber tree; it isn't native; it

doesn't need managing; it isn't an attractive tree.

Quandry over conserving Box whilst also realising a diversity of species. Box often

shades out ground flora and seedlings of other tree and shrub species.

Managing the dynamic nature and relative proportion of Box

scrub growing in an open landscape.

Slow-growing tree means a long wait for timber.

The nature of the current Box timber market (small,

specialist, informal, adhoc) can make it difficult to organise

harvesting and sale.

Difficulties in obtaining stock for planting schemes in terms of

provenance/ genetics and available quantities.

Concern that livestock might consume Box which is toxic to

them.

Paucity of scientific or other research or published material to

inform management of Box.

Confidence in the identification of native Buxus sempervirens

as opposed to cultivated varieties and other species.

Page 3Managing Box woodlands and trees in the countryside

There are positive steps that can be made to manage Box trees. It is important that Box trees continue to be a distinctive feature of the Chilterns Area of Outstanding Natural Beauty.

B.4 Managing Box trees to be healthy specimens

and recognising signs of stress

Based upon observations in the Chilterns and desk-based research, a description of a healthy

Box tree or woodland in a countryside setting would be as follows:

A healthy Buxus sempervirens plant grows vigorously, with verdant growth at the tips of

branches in the spring. Larger bushes may lack leaves inside the canopy where light cannot

reach but the outer branches are thick with leaves. The bark is undamaged and branches

are not rubbing against each other and roots are undisturbed. There is space for the tree to

grow and it is left to develop its natural form. Livestock are not compacting the ground

beneath and around the tree. The tree is successfully regenerating, with box seedlings in a

2-3m radius of the plant and/or the tree is layering. In a woodland, there is good diversity

of age, structure and genetic material. There are ancient and veteran Box trees. If timber

is harvested, it is done sustainably. There are no signs of pests and diseases, although some

can be tolerated in the countryside as opposed to the garden context, such as psyllid moth

and rusts which do not present a terminal threat. If pests and diseases are present, the

tree exhibits a healthy resilience to infection and there is ventilation to the tree to avoid

humid conditions.

Box is an adaptable plant and can grow in most soils, including acid soils. The optimal soil

pH quoted by Lynn Badorf (2003) is between 6.5 and 7.2 as this allows the proper soil

nutrients to be available. It can grow in full sun but can also tolerate shade. When

established, it can stand hard frosts, hot sun and strong winds.

It is useful to recognise signs of stress, pests and disease so that the tree and site can be

managed appropriately. Box blight and Box tree caterpillar are current major threats. It is

important to maintain awareness of reports about pests and diseases in the wider

landscape, particularly in relation to neighbouring areas of Box, and make preventative

measures, such as thinning, a routine management practice. Should prevention fail, then

diagnosis in the early stages and prompt corrective measures provide an advantage when

combatting an infection. Batdorf (2003; page 15)

Unfortunately, the early signs of disease are all too often overlooked or not understood.

Pests and diseases are covered in a separate section so a brief overview of signs of stress, as

described by Batdorf (2003), is provided here.

A plant can be stressed by biotic conditions, such as

pests and competing plants, and by abiotic conditions

such as water and temperature extremes. Lack of

vigour, including small leaves, discoloured leaves and

heavy fruiting are a sign of sub-optimal growing

conditions or stress. Those in full sun are often

troubled by mites and leaf scorch, as well as winter

discolouration and damage, whilst those in full shade

support sparse foliage and therefore reduced vigour.

Exposed sites also give rise to rapid temperature

changes which are detrimental. 'Winter bronzing' is

associated with situations of a south or west aspect.

Red and orange pigments in the leaves arise as a

result of chlorophyll (green pigments) being lost.

Windy sites will reduce the amount of water that can

be absorbed by the tree.

Managing Box woodlands and trees in the countryside Page 4

Keep an eye out for signs of poor vigour and regeneration, aiming to catch problems in a timely fashion. A deliberate effort may be necessary where Box is in locations that are little visited as part of day-to-day management.

B.5 Box Management calendar

April

March

June

February

January

December

November July

AugustOctober

September

MaySPRINGWINTER

SUMMERAUTUMN

FLOWERIN

GGRO

WIN

G SE

ASO

N

PRU

NIN

G

SEMI-RIPE CUT STING

LAYER

ING

SOFTW

OO

D C

UT

TIN

GS

Managing Box woodlands and trees in the countryside

Prune old wood during growing season. Avoid creating wounds if there is risk of exposure to frost or intense sun.

Take care to avoid frost damage.

The diagram below sets out how it may be best to time the range of management activities

applicable to Box throughout the year in the Chilterns.

This calendar should be used with caution. It is useful to observe Box at a particular

location over the seasons and carry out trials in order to understand the best timings for

management operations at that location. Frosts are possible from Autumn through to Spring.

Particular caution is needed for any treework affecting veteran or ancient or specimen Box

trees.

Note that there may not be regrowth around wounds created at this time of year. Take care to avoid frost damage.

Page 5

treework

propagation

plant phenology

GNI

NNI

HT

Bare rooted stock may be best planted in winter

COLLECT ED SE

SEEDS N R EIP

B.6 Managing for climate change

Box has attributes which make it relatively

resilient, including great longevity and multiple

regeneration strategies. It is a species that has

been identified as one which could see expansion

of its bioclimatic space in the British Isles by over

90% as a result of climate change.

When managing Box for the future, points to

consider alongside general climate change

guidance include:

1. Reduce other pressures such as pests and

diseases, pollutants, mis-management etc. This is

particularly important for those Box areas, edges

and isolated trees that are already stressed in

positions exposed to full sun or lots of frost.

2. Risk of pests and diseases is expected to increase with climate change. Adopt

appropriate biosecurity practices, involving monitoring and timely responses.

3. Maximise the resilience of the Box population by encouraging natural regeneration,

maximising core area and establishing a diversity of age, physical structure and genetics.

Carry out management activities at the ideal time of year to avoid undue stress to the tree.

Do not increase the risks of losing a Box population by unsustainably harvesting for timber or

undertaking extensive Box scrub clearance.

4. Adapt the conservation management of veteran, ancient and other specimen Box trees

to address climate change impacts.

5. Maintain Box in a variety of topographical situations to allow for differential impacts

and resilience. Box in sheltered Chiltern coombes (dry valleys) and along the springline will

probably be protected from extreme conditions, acting as refugia locations.

6. Bear climate change in mind when choosing locations for new plantings and planning

species composition. Climate change is expected to favour Box across a wider area of the

British Isles, in contrast to other native tree species which will see a reduction in suitable

bioclimatic space. Woodland communities and planting schemes on the Continent may

provide some ideas.

7. Climate change impacts upon Box trees and woodlands will have consequences upon

epiphytes living on Box. Targeted management will be needed.

8. Manage Box to provide for wildlife seeking shelter from extreme conditions. Refugia will

be increasingly important under extreme conditions and longterm stress, with Box around

springlines and in sheltered valleys potentially developing concentrations of species

diversity and numbers.

9. Manage livestock and people to ensure that their need for shelter from extreme

conditions does give rise to damage to Box. Maintain fences and access routes as necessary.

Managing Box woodlands and trees in the countryside

Various epiphytes are found growing on Box leaves at the box woodland SSSI near Great Kimble. Epiphytes are at risk due to climate change.

Berry et al (undated)

ibid

Morecroft et al (2013)

Porley et al (2005)

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2

3

2

4

3

1

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Page 6

B.7 Growing Buxus sempervirens - propagation

A number of options are possible when seeking to grow Buxus sempervirens.

Circumstances will dictate which propagation method is most suitable, as

set out in the table below. Propagation can be sexual or asexual/vegetative.

In all options, the following general considerations apply:

1. There needs to be confidence in the identification of the parent plant as

native Buxus sempervirens.

2. Pests and disease risks need to be managed carefully throughout the

propagation process. Parent plants should be healthy.

3. Information about exactly where the parent plants are growing should

be recorded and their progeny labelled with provenance information. Provenance is all-important. These Box seedlings are labelled in the nursery so that information about their parent tree can be traced.

Propagation technique

Considerations or constraints

Scheduling Relative difficulty and resources/costs

Time needed

Semi-ripe cuttings

Requires one or more healthy, vigorous parent plants from which to collect cuttings.Good option if lots of plants are needed. Box is often grown from cuttings. Plants are genetically identical to parent plant.

Collect cuttings early to mid summer when the current season's growth has stiffened; pot up urgently after collection.

Box is easy to grow from cuttings, relative to other plants. Pots, medium etc will be needed.

18 months to 2 years before hardy enough to plant out. Cuttings will take longer to root if collected outside of ideal collection period.

Seed from Chilterns Box trees

Seeds can be treated to eradicate pests and diseases. Seed is a propagation option for notable trees showing signs of disease. Plants are genetically different.

Collect ripe seeds late August/early September. Seed capsules ripen only in a good summer.

Slowest method for producing a plant.

Seed from seed sellers

Layering in the ground

Requires a healthy, vigorous parent plant with low-growing branches and existing or prepared bare ground around the base of the plant to bury branches. Ensure the layered plants are watered. Not the best option for producing lots of plants. Plants are genetically identical to parent plant.

Early spring to obtain rooted plants for the same year.

Really easy and cheap in terms of equipment needs. Large saplings created immediately.

Quickest method for establishing a plant.

Air layering on a stem

Requires a healthy, vigorous parent plant where it is possible to air layer. Need to monitor to ensure specimen remains secure. Not the best option for producing lots of plants.

Fiddly. Requires cheap materials. Large plants can be produced.

Quick method for establishing a plant

Managing Box woodlands and trees in the countryside Page 7

Seeds present only on some trees. Germination is not certain. Pots, medium etc will be needed.

Seeds may not be available from sellers. Seed should be free of pests and diseases. Issues regarding provenance.

Follow instructions provided with seed.

Germination is not certain. Pots, medium etc will be needed.

Not known.

Not known.

B.7.1 Collecting and growing from seeds

Seed can be collected when capsules have ripened in August-September. Batdorf (1997)

suggests that seeds will germinate very easily and uniformly if given a cold stratification

of 4°C for ten weeks. The Chilterns Box Woodland Project could not trial propagation by

seed but one Project volunteer successfully realised a shoot from one potted seed.

In the Kew Gardens laboratories at Wakehurst, germination specialists reported that two

tests of their Buxus sempervirens seed stock had failed (not UK seed) - one test linked to

low viability and the other to declined in germination. This indicated that there 'may be

dormancy issues' and 'this genus may be short lived'. Further testing on high viability

collections would be needed to give any degree of confidence to this finding.

B.7.1.1 Case study: Collecting Box seeds in the Chilterns for the

Millennium Seed Bank, Wakehurst

Box sprig collected in 2014. At the top of the photo, note the shrivelled capsule and black seed to the left, alongside a semi-ripe capsule with plumper black seed. The seed capsules on the sprig show various stages of ripening.

Germination specialist at Millennium Seed Bank, personal communication April 2014.

5

5

Growing from seed was not considered a viable

option for the Chilterns Box Woodland Project due

to time constraints. However, the Project collected

seed in September 2014 from Ellesborough and

Kimble Warrens SSSI and Wendover Woods to

donate to international stores at the Millennium

Seed Bank based at Wakehurst. Landowner

permission was sought and, in the case of the SSSI,

methodology agreed with Natural England to avoid

detrimental impact to the designated interest

feature.

In total, 10,908 seeds were donated; 4332 seeds

from Wendover (equivalent to 722 full capsules)

and 6576 seeds from SSSI (equivalent to 1096 full

capsules).

Since seeds arise from flowers, the collection areas focused upon box that was exposed to

sunshine beside glades, field boundaries and access routes. The interior of dense Box

clumps and wooded areas was therefore not sampled. In other circumstances, it may be

possible to access the tops of box trees within the interior of clumps to check for flowers

and seed capsules.

Seed capsules were pinched off the plant and then split open to check the seeds. Partly

opened capsules were preferable. Fully ripened capsules were loosely attached to the

branch, whilst less ripe capsules required a slight tug or pinch to remove them. Sometimes

capsules that were not fully ripe (partly green) were collected. Some seeds within ripened

capsules were found to have mould. By the end of September 2014, many capsules had

already ejected their seeds so collection was less successful.

In September 2014, capsules on a single tree were observed to be in various stages of

ripening, with those nearer the tip of the branch or in otherwise more exposed locations

being more advanced. In some instances, it appeared that failed capsules from the previous

year(s) remained on the branch alongside the current year's capsules. This was most obvious

where there were green capsules alongside shrivelled brown capsules. Fully ripened seed

capsules were observed to sometimes fail to eject all 6 seeds upon opening. It is important

Managing Box woodlands and trees in the countryside Page 8

to select the current season's seeds in case viability of

seeds is reduced for those capsules of previous year(s)

which failed to eject their seeds or ripen fully.

To ensure regeneration by seed would not be negatively

impacted by seed collection, it was important not to

remove all the seed capsules/seeds from any one tree.

Seeds were put into a cotton bag with string ties

provided by the Millennium Seed Bank. One bag was

used for each tree sampled. These bags allowed

ventilation to aid drying. Two matching labels were

made with small card jewellery tags; one to be held

inside the bag with the seeds and the other to attach to

the string-tied top. The label reference linked the

seeds to information about the parent plant etc.

The bags of seeds were carefully stored and then

posted to the Millennium Seed Bank. Silica gel in the

bags helped draw moisture away from the seeds.

A typical sprig of Box was collected from each of the

two sites as herbarium samples to accompany the seeds

at the Millennium Seed Bank.

Information about the parent trees and seeds was typed

up into a spreadsheet and sent to the Millennium Seed

Bank. The spreadsheet contained the following

information/column headings:

Collectors

Date of collection

Collection number – this is a Millennium Seed Bank

reference indicating collecting organisation, site

name and date, e.g. CCB/Wendover2014

Tree reference – this is a reference determined by collectors, e.g. W1, W2 (as in

Wendover 1, Wendover 2).

Number of seed capsules collected (where less than 6 viable seeds are contained in a

capsule, part capsules were combined to approximate the number of full capsules)

GPS reading for location of tree

Accuracy of GPS hand-held unit in relation to GPS reading (metres unless otherwise

stated)

Sampling location description – to compare with GPS reading

Form – description of tree form and leaves, e.g. layering, upright, narrow leaves,

yellowing leaves etc.

Diameter (where significant)

Height at which diameter taken (1.5m or before a fork, whichever applies first from the

ground)

Growing conditions and other notes – associated tree species, soils, topography.

Tagged (only significant girth trunks and trunks that can be safely reached are tagged)

Volunteer Dominic Harvey gently taps a metal disc tag onto a Box tree at Wendover Woods. Seeds from this tree were donated to the Millennium Seed Bank. The tag helps identify the parent tree.

Managing Box woodlands and trees in the countryside Page 9

B.7.2 Collecting and growing from cuttings

How to take cuttings

Wait until the current season's growth has hardened off, i.e. the new tip does not bend

too easily. It will be necessary to check the population/plants every now and then

during the growing season, e.g. once a week.

Select a parent tree. Record information about the parent tree on record sheet,

including its location. Give the tree a reference. This reference could be the GPS co-

ordinates if parent trees will be spaced far enough apart to have uniqe co-ordinates.

Use sharp secateurs to cut the branch just below a leaf. The leaf node is where

growth hormones are stored. 10cm long cuttings of the current season's growth are

needed. New growth must not bend too much. New growth on Box is identified by its

softer, misted leaves and by a stem that is not woody-looking. Strong, plentiful new

growth tends to be on the side enjoying the most light.

Wrap cuttings in tissue and secure with an elastic band. Then dampen the tissue.

Put the wrapped cuttings in a plastic bag that can be sealed (to retain moisture and

prevent spread of disease/pests). Freezer bags work well.

Note the tree reference on a label and stick to the plastic bag. It is best to use one bag

per parent tree.

Store the bags of cuttings in a cool bag to keep the samples from drying out. Take care

not to let the cuttings touch ice packs.

Urgently after collecting, plant up the cuttings or post to a nursery for potting up.

Essential basic principles for collecting cuttings

Use disinfected equipment. If you come into contact with disease or pests, it will be

necessary to disinfect before moving on.

Take cuttings from healthy, disease and pest –free trees.

Select trees with vigorous growth – these trees indicate greater amounts of growth

hormone which bodes well for propagation. It is also a sign of useful genetic material.

Account for losses from start to

finish. The National Trust Plant

Conservation Centre suggests as few

as 40% of the number of cuttings

will amount to successfully

transplanted seedlings.

Calculate how many cuttings need

to be taken from each parent tree.

Plan how to sample the population,

e.g. random or targeting specimen

trees.

Managing Box woodlands and trees in the countryside Page 10

Cuttings from a single tree were bundled together. A label notes the site reference and grid reference of the sampled tree. Kitchen towel was moistened to prevent drying out.

7.2.1 Case study: Collecting cuttings from Ellesborough and Kimble

Warrens SSSI

Three donor sites were selected based upon the Chilterns Box Woodland Project's interest in

growing plants which most likely came from native stock and contained valuable genetic

material. The focus was upon Ellesborough and Kimble Warrens Site of Special Scientific

Interest (SSSI) and Wendover Woods in Buckinghamshire, with a small sample from Aldbury

Nowers, Hertfordshire. Ellesborough and Kimble Warrens SSSI is regarded as one of few

native areas of Box in the country and also offered interest in terms of its status as an

ancient woodland with varied topography. Landowner permission was sought to allow

collection at each site and, in the case of the SSSI, the methodology was agreed with

Natural England to ensure no detriment to the designated features.

Collection of cuttings took place in August and September 2014 and in the cooler period of

the mornings to minimise the possibility of cuttings drying out and to allow for next day

delivery to the nursery for potting up.

In addition to the essential basic principles for collection, project-specific principles for

collection were added:

Sample to reflect the variety of growth forms present at the site, e.g. erect, layering

and various leaf shapes and sizes.

Large girth trees to be sampled.

Sample across the variety of growing conditions in terms of degree of slope, position on

slope and aspect.

Fourteen volunteers gathered cuttings from three Box sites in the Chilterns during August and September 2014. From left to right: Graham Bradshaw, Judith Waring, Valerie Tordoff, Clare Butler, Sarah Wright, Martin Schultze.

Managing Box woodlands and trees in the countryside Page 11

On a paper map, the box area of the SSSI was

divided into sample areas for the purpose of

ensuring collection was evenly spread across the site

and consequently representative. The three

coombes at the SSSI formed natural sampling units

and then the valley sides were sectioned. Within

these sample areas, the collectors could select the

most appropriate trees to sample. Routes through

the woodland offered easier and quicker movement

across the site but they were corridors for

disease/pests.

In order to obtain 500 cuttings, it was calculated

that 17 bushes would need to be sampled in each of

the 3 coombes. 10 cuttings would be taken from

each of the 17 bushes. It was also important to

gather together enough volunteers to collect this

material during the period agreed with the

landowner.

Trees showing signs of disease or pests or general

lack of vigour were not sampled; this meant that

some large parts of the SSSI that were most affected

by infection (e.g. Little Kimble Warren) and many

ancient trees were not sampled. A map showing the

location of diseased trees or most vigorous trees

would help focus collection of cuttings.

Managing Box woodlands and trees in the countryside

Practicalities of accessing suitable material was another constraining factor – dense Box

under which there was shade offered little foliage within reach and very steep slopes were

avoided for safety reasons.

When taking cuttings, co-ordinates of the tree

were recorded using hand-held GPS. To allow for

woodland cover and terrain giving rise to inaccurate

GPS readings, the accuracy reading was also noted

and the location judged by the collector marked on

the paper map. To help locate the tree at a later

date, trees of reasonable age/girth were also

tagged with metal discs hammered into the trunks.

Information about the tree was recorded, under the

reference of the GPS co-ordinates.

Cuttings were processed on-site as described in

previous section. Once collection was completed,

the bags of cuttings were quickly packed for

postage so that they could be posted for next day

delivery. To protect them from damage during

postage, bags of cuttings were put into cardboard VHS (video) boxes. Box cuttings are quite

bulky. The cardboard boxes were then put into a padded envelope and sent first class to the

National Trust nursery. 'Urgent, live plant material' was noted on the front.

Information about each parent tree was typed up into a spreadsheet and sent to the

National Trust nursery for their reference. This information was then linked to the National

Trust nursery reference system for each cutting they potted up.

The spreadsheet contained the following information/column headings:

Collectors

Date of collection

National Trust nursery reference – this reference became available only after the nursery

had processed the cuttings

Tree reference – this is a reference determined by collectors, e.g. W1, W2 (as in

Wendover 1, Wendover 2).

Number of cuttings collected – number of cuttings per tree

GPS reading for location of tree

Accuracy of GPS hand-held unit in relation to GPS reading (metres unless otherwise

stated)

Sampling location description – to compare with GPS reading

Form – description of tree form and leaves, e.g. layering, upright, narrow leaves,

yellowing leaves etc.

Diameter (where significant)

Height at which diameter taken (1.5m or before a fork, whichever applies first from

the ground)

Growing conditions and other notes – associated tree species, soils, topography.

Tagged (only significant girth trunks and trunks that can be safely reached are tagged)

Page 12

Sampled trees of a significant girth were tagged with a metal disc provided by the Millennium Seed Bank. This will help people locate sampled trees at a later date.

B.7.2.2 Case study: Growing Box cuttings in a nursery

At all stages, ensure there is no transmission of pests and diseases by people going in and

out of the nursery. At the National Trust nursery, tools and shoes were allocated to specific

areas of the nursery and foot dips at entrance/exit and disinfectants were in use.

Disinfectants in use by National Trust were Propellar and Jet 5. Where space is available, it

is recommended to keep plants in more than one location in order to avoid spread of pests

and diseases affecting the entire stock.

In August and September 2014, 407 cuttings were sent to the National Trust nursery: 30 from

Aldbury Nowers, 67 from Wendover and 310 from Ellesborough and Kimble Warrens SSSI. In

April 2015, there were 305 box plants growing in 9cm pots at the nursery: 25 plants from

Aldbury Nowers, 63 from Wendover Woods and 217 from SSSI.

Another 8 from Wendover and 174 from SSSI were still in Jiffy

plugs, presenting a maximum possible total of 487 plants.

1. The packages containing the cuttings were opened in the

'clean room'. Cuttings were screened for pests and diseases as

the first step. All cuttings were tested for Phytophera and found

to be clear. (Any positive results lead to immediate incineration.)

There is currently no test for box blight. Cuttings were also

soaked in a sink of 20% bleach concentration for several hours

(generic minimum time is 20 minutes). Some cuttings were

soaked for more than 24 hours in bleach without negative

consequences, although this long soaking is not recommended.

(In the case of large plants that cannot be soaked in bleach,

there is a period of quarantine for 6-8 weeks to check for pests

and diseases). The cuttings were then rinsed.

2. Cuttings were cut so that, in some cases, two to three

samples were made. Cuttings were inserted into moistened Jiffy

plugs and held in plastic trays. Plugs were labelled so that each

plant could be identified and linked to information about where

the cutting came from etc. These plugs comprise of a dry coir

compost which expands with water and is held together by a thin

membrane. The advantage of these plugs is that they can be

lifted up to check for rooting. These cuttings are kept moist by

regular misting in a greenhouse. Remove any plants showing signs

of pests and diseases. In

this case, several were

removed due to signs of

scale.

3. Once rooting is

observed, the Jiffy plugs

are planted directly into

bio-degradeable 9cm

height pots in plastic

trays (18 pots to a tray).

Managing Box woodlands and trees in the countryside

Jiffy plugs of coir compost sitting in their plastic tray. Plug on the left has been moistened so that it has expanded and is ready for a cutting.

Cuttings are kept out of direct sunlight in a greenhouse and under timed misting system. Cuttings are assigned a unique reference number and labelled.

Page 13

It is easy to check if the Box cutting is rooting when it is grown in a Jiffy plug rather than a plastic tray or pot.

The compost used in pots is peat-free, coir-based commercial

blend (known as T2). These pots receive regular watering in the

greenhouse – it is important the biodegradable pots do not dry

out. The temperature is regulated. Remove any parts or whole

plants showing pests and disease. Some plants were observed

with rust.

4. If the plants are to be transported, it is easier to do so

when the plants have grown up to 8cm in height.

5. [The following steps will take place after the Lottery-funded

period of the Chilterns Woodland Project has ended]. Once

rooting out of the pot is observed the plants need to be

transferred into larger 1 litre 'air pots'. This is likely to be after

a year of growth. These pots comprise a twisting roll of plastic

with holes around the sides to encourage side rooting. The top

lip of the smaller biodegradeable pot needs to be stripped off

for planting into the larger pot. They need to be kept in a

greenhouse or sheltered setting until ready for planting out in

18 months to 2 years. Again, remove parts or whole plants

showing pests and diseases.

Managing Box woodlands and trees in the countryside

Jiffy plugs are potted into 9cm pots. Labelling is important to ensure the provenance/ information of each plant can be traced.

The roots of this plant (not Buxus sempervirens) show that it is ready to be potted on from its current 9cm biodegradeable pot.

Various plants in 'air pots' in the greenhouse. Note the irrigation system and labels. Box cuttings will be ready for planting out in 18 months to 2 years.

Page 14

B.7.3 Propagation by layering – 'air' and buried

Box layers naturally when branches lie on the ground – it self-layers – and so layering as a

propagation method is relatively easy and Box is quick to root compared to other plants.

Layering by burying

1. Look for a suitable, healthy parent Box plant – the plant needs low-growing, non-

flowering branches and space around the base for layered plants to grow. This situation can

be found at the edge of a clump of Box trees or an individual Box tree.

2. Bend a low-growing branch to the ground (it must not be likely to break – some Box

branches exhibit a natural tendency to curve down to the ground) . The branch should be

flexible and long enough that 30cm from the tip will be left protruding from where the

branch is buried.

3. At the point on the branch where it touches the ground/will be buried, clip off the

leaves and any side branches along a length of 5cm so that the part of the stem to be

buried is clear.

4. To assist rooting,

use a sharp, clean

knife to make a

slanting cut through

the underside of the

stem at a leaf joint

(the point where a

leaf meets the

stem). Make this cut

2.5cm to 5cm long,

running through the

leaf joint. Ensure

the cut goes no

deeper than half the

width of the stem.

(It is not essential

to make a cut, but

it increases the

likelihood of

rooting).

5. Hormone rooting

powder can be

applied to the cut area but it is not essential.

6. Bend the branch down to the ground to confirm where to make a small trench to bury

the stem. Dig to a depth of around 5cm using a hand trowel or stick if the ground is soft.

7. Carefully press the prepared length of stem into the trench. The cut stem should open

up when the branch is bent down into the trench but you can use a toothpick to wedge the

wound open.

8. Fix the stem in place with a metal peg or bent wire or a peg fashioned from a forked

tree branch. Make sure the peg is firmly in place if you think the wind or burrowing animals

could disturb the branch.

Trim off branches and leaves along the 5cm section of branch to be buried. From this buried section, allow 30cm at the end of the branch to develop into a new plant.

Managing Box woodlands and trees in the countryside Page 15

Managing Box woodlands and trees in the countryside

9. Bury the stem with

soil and pack down

firmly. The finished level

of soil should be slightly

higher than the

surrounding ground

level. In a non-

countryside setting, it is

suggested that grit and

potting compost is added

to the trench but this is

not appropriate or

necessary in a

countryside setting.

10. Use a heavy stone

to further anchor the

stem into the ground

and also to retain

moisture. In the

Chilterns, large flints

can be used from the

local area. These stones

are important in

situations where the pegs could come loose and also helps identify layered plants.

11. In a non-countryside setting, it is suggested that the end of the layered branch is

attached to a cane to help it grow upwards. This is not necessary unless an upright growth

form is required.

12. If rain is not forecast soon after layering, consider watering the filled trench.

13. Tag your plant and layered branches so that the plants can be found easily in future.

Make a written record as appropriate of the location and number of branches layered etc.

Air layering

This method was not tried by the Chilterns Box Woodland Project but Glynn Miller, a

groundsman, reported that he had successfully grown box in this way.

1. Cut away a half inch strip of bark all the way round the branch and apply a rooting

hormone to the exposed wood.

2. Wrap damp sphagnum moss or damp kitchen towel around the cut area and then wrap

plastic such as cling film around the cut, fixing it securely so that it is water-tight but

allowing space within the plastic for growth of roots.

3. Once roots have formed, cut the rooted branch off the parent plant. Plant this rooted

branch at the receptor site.

The cheapest and most environmentally-friendly option is to make pegs from forked tree branches. A peg is needed to secure the buried branch in the ground.

Page 16

Managing Box woodlands and trees in the countryside

B. 7.3.1 Case study: Layering Box at Wendover Woods

An area in Wendover Woods was selected using the following criteria:

1. Numerous suitable established Box trees with branches growing low to the ground and

out into grassland. Box trees were healthy, showing no signs of disease.

2. Area little visited by the public in order to reduce the possibility of people and dogs

disturbing layered branches.

3. Close to Forestry Commission office and equipment. Area under management, e.g.

grassland strimmed occasionally to control weeds and scrub.

A group of volunteers set to work in June 2014 to trial layering of Box in the selected area.

The objective was to use materials available on-site and so minimise monetary cost. Some

volunteers used only heavy flint stones to

secure the layered branch, whilst others

used a peg fashioned from tree branches.

No rooting powder was used and the

buried sections were not cut.

In April 2015, the layered branches were

checked.

Stones remained in place and, as large

white flints, were useful as markers to

locate the layered branches. Layered

branches were seen to be rooting and the

leaves looked healthy. However, as little

as one root was observed on some

layered branches.

This trial demonstrated that layering is

productive when carried out in June and

with minimal equipment but it did not

give rise to extensive rooting. Better

rooting is more likely if layering is done

in early Spring; rooting powder is used; a

section of buried branch is wounded, and

the layered branch is allowed adequate

time to root.

Page 17

As part of the layering trial at Wendover Woods, a buried branch is pulled out of the ground in April 2015 to reveal a single root.

A peg and flint stone were used to secure the buried branch in place (see centre of photo). After 10 months, this layered branch remains fixed in the ground, whilst leaf litter and vegetation has encroached.

B.8 Planting Box in the countryside

Whilst Box appears to thrive in many places where it is found in the Chilterns, it is possible

that a landowner may wish to introduce Box plants rather than rely on, or wait for, natural

regeneration. Grants from the Forestry Commission and others may be sought for planting

Box, as illustrated by the Wormsley Estate case study in this publication.

Before planting, it is recommended that the following questions are considered. The

Forestry Commission should also be consulted as routine practice for planting schemes.

Additional considerations specific to planting Box are set out later in this section.

1. Is there a history of human intervention such as planting at the site? It is less appropriate

to plant in an area where natural regeneration and other natural processes are operating

and where the species composition is strongly native in composition. There would be less to

debate if planting was in already heavily modified woodlands or planted forests.

2. What will be lost if Box is planted and is there anything that isn't compatible with Box?

Steep chalk slopes offer suitable conditions for Box but also support other interest features

that could be negatively impacted by Box including species-rich open chalk grassland and

historic earthworks. Box is toxic to livestock, although some livestock appear to have

learned to avoid eating box.

3. When do we want to realise outcomes? Box grows in girth slowly, meaning that timber

value can be realised only after many years.

4. Are there adequate resources to manage Box under future circumstances? This is

particularly pertinent where dominance of Box may give rise to loss of valued areas of

grassland or a decline in species diversity in the scrub community. If it is to be used as game

cover, there needs to be management dedicated to maintaining dense cover at ground level.

Impact of climate change and other broad environmental factors, such as non-native

invasive species and pollution, need to be considered.

5. Is there a history of Box blight or other relevant pests and diseases in the area? It is not

advisable to plant Box where there is a history of Box blight, particularly if appropriate

eradication has not been carried out.

Managing Box woodlands and trees in the countryside Page 18

Box seedlings are easy to transplant but, as with any planting scheme, think before you plant!

Managing Box woodlands and trees in the countryside

B.8.2 Selecting sites to plant box

There will be circumstances that are more or less suitable for planting native Box:

1. To conserve and extend upon an existing population. Such situations include the

Page 19

Type of planting stock

Considerations or constraints

Scheduling Relative difficulty and resources/costs

Time needed

Transplanting your own propagated stock

Fully informed about provenance of stock.

Waiting time for stock to be ready.

Transplanting established trees from the countryside

Seedlings and young trees can be transplanted. To avoid negative impacts upon donor site, requires a healthy, expanding population. Requires suitable transport options between donor and receptor site.

Bare rooted plants are best planted in winter.

Costs linked to labour, transport and after-care. Plants will suffer if there is a lack of rain/moisture in soil.

Quickest method.

Buying plants from a nursery

Genetics or provenance is sometimes not easily traced. Many commercial nurseries obtain stock from abroad, although the source of the material may be from UK.

It is often necessary for large planting schemes to make advance orders for plants.

Availability of stock will dictate what is possible.

There are various options to consider when sourcing and planting trees, as set out in the

table below.

Full control over scheduling.

Requires in-house resources.

Box is relatively expensive to purchase from nurseries.

B.8.1 Sourcing stock to plant

It is important to request native, untrained/unclipped Buxus sempervirens as there is a

plethora of cultivars and topiary available through commercial nurseries. In addition, it is

strongly recommended that nursery stock destined for planting in the Chilterns countryside

should be of local provenance, i.e. UK at the very least. Common trade practice is to

purchase young plants grown abroad, although the genetic material may originally come

from the UK. Nurseries selling UK genetic stock of various tree species can be found near

the Chilterns but Buxus sempervirens is not often available. Ideally, partnerships can be set

up with nurseries or in-house nurseries can be developed which will generate stock from

local provenance seed, cuttings and/or seedlings.

It may be necessary to pre-order Box plants to ensure a nursery can supply adequate

quantities for large planting schemes. This makes it important to plan ahead.

Care should be taken to avoid carrying pests and diseases on nursery stock.

There may be opportunity to source stock from the countryside, with Box seedlings

conveniently growing in dense patches in some locations. When digging, take care not to

disturb roots of trees to remain in-situ.

Managing Box woodlands and trees in the countryside Page 20

restoration of a population's historic extent around remaining relicts; to boost a small

population's resilience to disease or its genetic diversity; to increase the species and/or

structural diversity of an area of native chalk scrub or beech woodland; to restore a

neglected planting scheme in a designed parkland landscape. Where the purpose is to

conserve native Box populations, such an initiative would be best undertaken following

further strengthening or conclusive evidence about the native status of Buxus sempervirens

in Britain and in the planting location. Equally, planting for the sake of conserving historic

interest would receive greater support with stronger evidence of historic significance or

relevance. For example, there are some historic uses of Box, such as Box planted for game

cover, which may not be considered a high priority for conservation efforts. The perceived or

actual threat of Box blight and other pests and diseases will drive the pace or urgency of

conservation efforts and, because Box is slow growing and takes years to achieve dominance

in the canopy, the point in time at which Box is planted is significant.

2. To re-create a known historic planted population that is no longer present in the

landscape. This may become increasingly relevant should Box blight or other pests and

diseases cause significant damage to current populations. It is likely that recreation of some

designed landscapes and historic boundaries may involve planting of native or Chilterns

provenance box, including Roman villa sites. However, fine scale geographic information and

other information about planting densities etc is usually absent in historic documents and so

any planting scheme will be notional.

3. To re-introduce box to a semi-natural habitat where there are historic records to suggest

it once grew there. Such an initiative would be best undertaken following further

strengthening or conclusive evidence about the native status of Buxus sempervirens. Nature

conservation organisations such as the Wildlife Trusts have established policies and

procedures for species re-introductions that can help determine if Box is appropriate.

However, fine scale geographic information and other information about planting densities

etc is usually absent in historic documents and so any planting scheme will be notional. For

example, descriptions of Chilterns locations of Box in historic travel diaries include a vague

reference to the 'hills above Dunstable'.

4. To create a new area of Box without known historic precedence. Where there is an

interest in planting box for timber, any soils apart from waterlogged will support Box and Box

may be one of the few timber species to consider on very steep slopes or loose, dry soils or in

dense shade. For biodiversity reasons, there may also be a desire to create new areas of

beech and yew woodland with an understorey of Box or to create a mosaic of grassland with

scrub that incorporates Box. It may also be suitable to plant Box in Chilterns churchyards and

other public places to celebrate the cultural and historical significance of Box.

5. To prevent widespread disease and pest impacts, it may be best to conserve and/or

create resilient populations/areas of Box in a way which guards against spread of infection,

e.g. spatially separate woodlands. See above paragraphs for further guidance around planting

Box to conserve or create new areas.

6. To create woodlands or other wooded features which are more resilient to climate

change. To further the conservation of Box and its associated semi-natural habitats, Box

could be planted in sheltered positions and small populations could be extended to increase

core area. It may also become a more popular species to plant as predictions suggest its

bioclimatic space will increase across the British Isles. Box could form part of new species

mixes that are expected to create woodlands and timber suited to future climatic conditions

– see climate change section for details. Box could also be planted to provide shelter to other

features of interest.

Berry et al (undated)

6

6

Managing Box woodlands and trees in the countryside

B.8.3 Case study: New Box plantation managed for game at

the Wormsley Estate

Beginning in 2011, a consultant worked with the Wormsley Estate in the Chilterns to design

and realise a Box plantation scheme. The vision was to create closed canopy box woodland,

with the reference sites being three Box woodland SSSIs in the South East which the

consultant visited. From a business perspective, this provided the estate with an

opportunity to make the most of marginal land and provide for game birds. The Forestry

Commission provided funding under the England Woodland Grant Scheme to support

biodiversity outcomes, whilst other funders sought public engagement and potential Box

timber for musical instruments.

Various plots were selected on steep chalk slopes where previous plantations of other tree

species, including Beech, had failed and where there was no existing chalk grassland plant

interest. One plantation could be viewed from a public footpath alongside which an

interpretation board was erected about the plantation.

Planting up of plots was phased over several years starting in 2012 with a trial plot. The

plantation sites were prepared for planting by clearing bramble, but large fallen Beech

were left as natural features and young Hornbeam were retained in some plots. The

plantation areas were fenced with 1.5m pig fencing which suits pheasants. Stiles or gates

were installed to allow access for maintenance and beaters and to remove deer. Paths were

provided for beaters.

Box plants in 9cm pots (P9s) were purchased from commercial nurseries. Unfortunately, the

provenance of the stock was not confirmed and was described as 'European Box'. In 2012,

only Box was planted in the trial but in 2013, the species mix comprised Box at 95% and

then 5% Juniper, Spindle and Privet. In 2014, Juniper was omitted. The consultant reported

difficulties in sourcing sufficient quantities of Box from nurseries. Many nurseries grow

large numbers of Box plants on-order only, i.e. could not provide plants immediately and

needed time to grow the plants to P9 stage. Once delivered to the estate, nursery stock

was stored and cared for in a barn until planting.

Planting was done on foot with wheel barrows and hand tools, working downhill. The flinty,

chalky ground made tough digging. The holes were not prepared in any way, e.g. no

fertilizers. Planting made the

most of favourable weather

conditions as much as possible.

Two hundred Box plants were

planted in 4 hours by 8 volunteers

in February 2012. In April 2013, a

team of 3 contractors planted 900

a day.

An unfenced trial plot planted in

February 2012 revealed that deer

may pull plants up and toss them

to the side - thirty plants out of a

hundred were lost in this way.

Deer also appeared to bite off and

spit out the tips of plants,

although this did not affect

growth in the longterm.

Page 21

A team of three contractors planted 900 plants a day. Stock was bought from a nursery in 9cm pots.

Managing box woodlands and trees in the countryside Page 22

In the fenced plots, Box took well with 100% success in some and the most lost being 5

plants in a plot. Healthy new growth was observed. In July 2013, a heatwave caused die-

back in the herb layer but not amongst Box planted in April. Of the 2013 planting, Juniper

failed immediately in some cases and saw 50% losses, whilst there was a much lower 20%

loss for Spindle and Privet.

The plantations at the Wormsley

estate are a good illustration of

what can be achieved with Box.

The potential for the estate to

propagate plants from

established Box on the estate

would ensure provenance is

known for future plantings.

Planting density was high to create a dense Box scrub in future. Note the fencing to enclose the plot and the steep terrain.

Managing Box woodlands and trees in the countryside Page 23

B.9 Treework for Box trees

Treework may be needed to maintain a tree in a safe or stable condition, to remove

diseased parts, to promote growth, to provide timber, to keep access routes or other

features clear or to manage appearance. There are various types of treework that could

achieve these objectives and advice can be sought from a trained arboriculturalist or

forester on what is most appropriate. Work will differ between formal and informal settings

for Box trees, with topiary being a well-known feature of Box in gardens.

This publication focuses upon informal countryside settings and does not cover topiary.

Please refer to the numerous publications and websites providing advice on this subject. The

European Boxwood and Topiary Society is a possible starting point.

A Box tree may be legally protected so check for Tree Protection Orders, Conservation Areas

and Sites of Special Scientific Interest before carrying out any work.

Tree work should not be carried out when there is a risk of wet conditions which encourage

pests and diseases.

Every pruning cut inflicts a wound on the tree. Size, angle and position of the cut are

significant and as a general rule, pruning should be avoided during the time of leaf

production (when the tree draws on its energy reserves) and at the time of leaf fall (when

the tree stores energy). Box grows more vigorously in Spring and so will produce bushier

growth and shoot more quickly if cut at this time. Hard pruning of established trees or of old

wood is best done in late Spring. Allow time for it to recover (for wounds to lignify) before

frosts, bearing in mind it is slow growing – watch out for Spring frosts. Sunny days are not

ideal since burns are possible. It is best to avoid tree work when a tree is under stress.

Trained arboriculturalists and foresters should ideally carry out any work, particularly in

relation to ancient or veteran or diseased or other

'specimen' Box trees.

Deadwood should be retained for biodiversity

reasons, where possible.

Where a Box tree is being harvested for timber, it

has been suggested that wood is felled between

October and Christmas, taking care to avoid frosts.

The Chilterns Box Woodland Project learnt of only

two businesses working in England today with any

reasonable experience of harvesting Boxwood.

Whilst understanding and practical skills are limited,

it is important to take a precautionary approach. For

further details, see section and case study about

harvesting timber.

Thinning can help guard against humid conditions

favouring pests and diseases including Macrophoma

leaf spot and Box blight. Please see separate section

about pests and diseases for further information.

Branches of dense foliage are removed or cut back

to create pathways for air and light into the centre

of the tree or through groups of box trees. Air

circulation and sunlight penetration will also aid

evaporation of water within the tree. Thinning

Mature Box has been pruned back by estate workers to stop encroachment into a woodland glade. Most trees exhibited healthy regrowth but this tree would benefit from thinning. Trained arboriculturalists can provide useful advice in such cases.

Managing Box woodlands and trees in the countryside Page 24

should aim to make the interior of the bush visible from one or more points of view or break

up a clump of Box trees. Batdorf (2003) suggests carrying out thinning in Winter to deter

regrowth that would undo the thinning work.

In an informal countryside setting, thinning to manage disease would apply to:

1. An individual tree that has dense outer foliage, particularly if the foliage touches the

ground.

2. Trees growing in large, dense clumps in a grassland or in a woodland.

3. Trees beside access routes should be targeted for general biosecurity reasons because

vehicles and people are vectors for some pests and diseases. Trackside trees that are

regularly clipped or sheared to keep access routes clear of overhanging vegetation are

particularly vulnerable.

4. Trees in damp or poorly ventilated conditions such as in sheltered, very narrow coombes

and at the bottom of slopes of Chiltern valleys and escarpment, i.e. the springline where

watercourses emerge.

5. Trees known to be affected by pests and diseases or near to affected trees. It may also

be precautionary to thin trees if pests and diseases are known to be at a nearby site and/or

if vectors of the disease are associated with the site, e.g. publicly accessible sites.

Managing Box woodlands and trees in the countryside

B.10 Managing ancient and veteran Box trees

Conservation management must take particular care with ancient and veteran box trees

because they are slow-growing and Box trees of a large girth are special in the Chilterns.

The large girth trees are targeted for timber by some woodcrafts so sustainable harvesting

is particularly pertinent.

General guidance about the management of ancient and veteran trees apply to Box, with a

key publication being Veteran trees: a guide to good management by English Nature (2000).

To conserve a tree and its timber value, it is advisable to minimise wider environmental

pressures such as pollution as well as direct impacts such as ground compaction and

disease. The time of year when management activities are carried out should adhere as

closely as possible to the management calendar included in this publication in order to

reduce risk of weakening or harming veteran and ancient Box trees. Further details about

treework is provided in the section 'Treework for Box trees'.

Points to note that are specific to Box are:

1. Burrowing animals and livestock are attracted to the shelter offered by Box and as a

result can undermine roots, damage bark, alter soil chemistry and encourage ground flora

that may compete with Box seedlings. Fence off livestock from specimen Box tree(s).

2. Box is a heavy wood and cracking is increasingly possible with age. Whilst Box will layer if

gravity finally brings a branch to the ground, the timber value will decline if the bough

splits and broken bark makes the tree susceptible to pests and disease. If these issues are a

concern, it may be best to remove weight from a Box tree to avoid collapse and cracking.

3. As a tree of great longevity, the genetic material could be valuable. Consider collecting

seed and cuttings from specimen trees in order to secure future progeny. Manage the tree

and surrounding area to encourage natural regeneration too.

This Box tree in Wendover Woods has lost much of its timber value, although it retains biodiversity value as a veteran tree. With management and monitoring, it may have been possible to harvest one or more of the fallen trunks before they collapsed. Two trunks remain upstanding.

Page 25

Managing Box woodlands and trees in the countryside

B.11 Managing established Box woodlands and Box

scrub, including managing for timber

As with any semi-natural woodland or area of scrub, it is usually desirable to adopt a

minimal intervention approach when and where natural processes are operating well but,

where natural regeneration is failing or there are pest and disease threats, take action.

Where the natural processes of succession of grassland to woodland or dominance of Box

over other tree and scrub species needs to be arrested, management must intervene to

control the expansion and perhaps also the long-

term persistence of box. Box growing along access

routes will need to be cut back. In woodlands

where there are specific timber requirements,

targeted management may be needed to

encourage particular growth forms or ages of

trees.

A management calendar is provided in this

publication to aid scheduling of different

management activities throughout the year.

Weather conditions, pests and diseases, as well as

available resources, will constrain how

management can adhere to this calendar. Box has

been neglected in the Chilterns for much of the

recent past so it will take time to incorporate Box

into management activities. Despite this history

of neglect, Box has managed to survive and continue to expand in many places in the

Chilterns but there is an immediate need to address threats of Box blight; ensure that Box is

resilient to climate change, and carry out any necessary restoration.

Where box is failing to regenerate through seed, it may be necessary to increase light levels

to encourage flowering and to clear surrounding ground of competing vegetation cover. At

Boxmoor and at Ellesborough and Kimble Warrens SSSI, for example, it was observed that

thick moss mats were probably preventing seedlings from establishing. It may be sensible to

encourage regeneration by seed even where layering is taking place because layered plants

are clones which limit genetic diversity.

Thinning and gap creation in

dense, single-age stands and

also in extensive areas of

layering Box will improve age,

structural and genetic

diversity as well as facilitate

ventilation guarding against

fungal infections. Gap

creation may also provide

opportunity to other plant

species which would

otherwise be shaded out or

out-competed by Box; this

would boost biodiversity in

the area and potentially

provide habitat for fauna.

Thick moss mats may prevent seedlings from establishing. Box seeds were found underneath this moss in the photo.

Over many years, Box at Shirburn Hill SSSI has been allowed to encroach onto species-rich chalk grassland and overwhelm Juniper. There are numerous Juniper carcasses in the dark interior of the Box scrub at Shirburn. The dynamics of a grassland-scrub mosaic need to be managed if certain elements are not to be lost to long-term competitive plants such as Box.

Page 26

Managing Box woodlands and trees in the countryside

Where Box grows adjacent to areas that are valued in their own right, it will be necessary to

prevent Box encroaching into these areas. Box in the Chilterns is often seen gradually

encroaching onto chalk grassland, as at Shirburn Hill SSSI and Ellesborough and Kimble

Warrens SSSI.

Conservation of specimen or other important trees within a woodland or scrub area is a

consideration too – this is covered in another section.

Management objectives will directly or sometimes indirectly cater for timber. During the life

of the Chilterns Box Woodland Project, only two small businesses were identified as having

first-hand experience of managing Box woodlands for timber. One of these is John Pepper's

small family business working with landowners to manage Box woodlands in various counties

for the purposes of harvesting Box timber to make traditional Northamptonshire skittles and

cheeses. Since his father's time, John has had to travel further to find suitable woodlands.

The Pepper family have learnt through experience that the best time to cut Boxwood for

their purposes is from mid-October to Christmas.

Restorative work may be needed before a woodland is viable as a timber interest. John

inspected one Box woodland in the Chilterns that had been left unmanaged for at least 100

years. He suggested that a good amount of restoration was needed, including extensive

thinning, and that some useful timber would come out of this work because there were

large girth trees in the wood. In this instance, the restorative work required was so great

that John would only consider the job if the landowner was not to require any payment

linked to the work.

Box is gradually encroaching onto the grassland at Shirburn Hill SSSI. The dense Box scrub lies down the slope, with Box advancing up the slope into the foreground of the photo.

Page 27

Managing Box woodlands and trees in the countryside Page 28

Boxwood is used by a variety of woodworkers, being

particularly associated with engraving and woodwind

instruments. Each use will have its own specifications for

timber, although density and colour are commonly the key

attributes of interest. Boxwood is typically sold in log form.

Note that even small dimension Boxwood logs can be of use

to some woodworkers.

Due to the market for Boxwood being small and specialist, it

is strongly recommended that a buyer or user is identified

prior to planning or commencing any harvesting. The

Chilterns Box Woodland Project developed an initial list of

contact details of buyers and users of Boxwood which can be

obtained from the Chilterns Conservation Board. Work can

then be designed to meet their needs and so minimise

wastage. It is particularly important to avoid unnecessarily

removing wood from veteran or ancient or large girth or

specimen Box trees.

Where a Box tree is being harvested for timber, it has been

recommended that wood is felled between October and

Christmas, taking care to avoid frosts. According to an

experienced Box woodworker, John Pepper, cutting at this

time is more likely to produce good quality timber. However,

initial observations by the Chilterns Box Woodland Project

suggests re-growth may not occur from stumps cut close to

the ground. It is important to weigh up the needs for timber

and conservation of the tree in question. The Chilterns Box

Woodland began trials into the timing of cutting operations

such as coppicing to establish whether it is possible to obtain

good timber quality whilst also ensuring healthy re-growth. In

the meantime, a precautionary approach should be taken,

e.g. only harvest a selection of stems from a multi-stemmed

Box tree.

B.11.1 Harvesting timber

Box is ideal for producing fine detail engravings. A woodblock needs to be consistently smooth, dense and without dark discolouration.

Chris Daunt makes woodblocks for engraving from rounds of Boxwood. He buys in log form and sometimes seasons it himself.

Managing Box woodlands and trees in the countryside

B.11.1.1 Case study: Harvesting timber from a Box plantation in

Norfolk

On a visit to a Box plantation in Norfolk in

November 2014, John Pepper and two men

worked on foot with chainsaws to harvest

Box timber. They sought large girth Box

since the cheeses are large rounds cut from

half round sections. The team felled the

tree in stages, first cutting off the side

branches through to a final step of cutting

the lower section of trunk which was liable

to splitting if not cut correctly. The trunk is

cut as close to ground level as possible in

order to obtain large girth sections. The

trunks are cut into 1 metre length logs to

carry by hand through the wood to a vehicle

for transportation off-site.

The Box was also harvested in a way which

increased light levels in the wood so that ground cover for game birds was improved.

Observations at the Norfolk site suggested that on-site burning of unwanted arisings, such as

side branches, appeared to give rise to a change in ground flora which competes with Box

and other desirable regeneration over at least a few years, e.g. common stinging nettle.

It was also concerning to note that Box which had been felled to ground level in previous

years was not regenerating from the cut stump. To ensure harvesting is sustainable in terms

of maintaining the population of Box in any area, it is recommended that a precautionary

approach is adopted when harvesting timber:

1. Avoid wholescale coppicing of

specimen trees or other significant Box

trees as there is a risk of loss/no

regeneration.

2. Make sure natural regeneration of Box

is highly likely following harvesting. This is

preferable to re-stocking by planting. Note

light levels and regeneration in the area

surrounding the tree.

3. When harvesting a multi-stemmed

tree, fell only some of the stems and leave

some intact.

4. Rather than felling to ground level, fell

a trunk above the lowest sprout/branch so

that existing growth points are conserved

and so give greater chance of regeneration from the cut stump.

When harvesting or cutting Boxwood, care needs to be taken to ensure regeneration. Low light levels are not encouraging re-growth from these stumps which were cut years ago. Fortunately, the remaining trunks ensure the tree persists.

Ben Pepper works with John Pepper and one other to fell Box with chainsaws in a wood in Norfolk. Wood is seasoned using a technique developed by John. The Pepper family then work the wood to produce the traditional Northamptonshire skittles and cheeses.

Page 29

Managing Box woodlands and trees in the countryside

B.11.2 Case study: Coppicing in Wendover Woods

An area of densely growing Box was identified as likely to benefit from

thinning and increased structural and age diversity. In this area, a 10m x 10m

plot was located as a trial plot for coppicing. This plot was selected to avoid

including any significant veteran or thick girth Box in the trial. Coppicing was

sufficiently distant from public access routes in order to avoid the public

bringing pests and diseases to the newly cut stems. An edge of box was also

retained between the plot and public access routes in order to avoid

complaints about the appearance of the coppiced box.

In June 2014, Chiltern Society volunteers worked with a local experienced

woodworker to fell trees in the trial plot. The trees were felled above ground

level, often leaving sections with short sprouting branches. Standard bow

saws were used but Silky saws were thought to be most effective. Straight

stems of various girths were selected as potentially useful for woodworking

and their side branches lopped off.

The intention was to carry out coppicing in another trial plot nearby in

September 2014 for comparison. This did not take place however.

In April 2015, the coppiced area was re-visited. Side shoots looked healthy

but there was no evidence of growth from the cut surface. Conclusions

regarding the regrowth of the coppiced trees will not be possible for a good

while yet.

Box trees were coppiced at a trial plot in Wendover Woods in June 2014 to test regeneration and timber potential. Chiltern Society volunteers record details about the trees.

Light green leaves of new growth indicate this tree at Wendover Woods has survived coppicing ten months previously. No growth is evident from the cut surface. The bark damage may cause problems in future.

Page 30

Managing Box woodlands and trees in the countryside

B.11.3 Managing Box along access routes

It is important to consider how to prune Box trees in a way that is appropriate to the setting

and does not have negative impacts upon the vigour of the tree.

Cutting back of Box along an access route may create the appearance of a hedge that may

look at odds with the more informal appearance of the surrounding countryside.

The time of year and weather conditions are also significant if there is a risk of pests and

diseases and there are ancient or veteran trees. The management calendar in this

publication provides some guidance regarding the timing of management activities such as

pruning.

Pruning of established Box

trees along access routes

has the potential to produce

valuable timber so it is

worth contacting

woodworkers or other

interested parties to explore

possibilities.

A Box tree in the foreground has been cut back to keep a bridleway clear. Pruning was carried out with little knowledge of what is appropriate for Box trees. Large girth branches were discarded on the ground. In the background along the bridleway, management is inadvertently creating a formal hedge-like appearance at odds with the wider woodland.

Page 31

Managing Box woodlands and trees in the countryside

B.12 Managing pests, diseases and other problems,

including biosecurity recommendations

Box trees can host a range of pests and diseases and there are management challenges

specific to countryside settings, e.g. livestock. This publication picks out the most

commonly observed in the Chilterns, including those that cause extensive damage. There is

useful guidance about Box provided by the horticultural sector, but this publication

addresses a gap by providing information that is relevant to the countryside as opposed to

the garden. Further details and information about other pests and diseases can be found in

numerous publications and online, with the Royal Horticultural Society website being a good

starting point.

The Forestry Commission states that 'biosecurity measures are the practical steps designed

to minimise the risk of introducing and spreading pests and diseases'. There are

invertebrate pests that are harmful to trees and diseases of trees caused by bacterial and

fungal pathogens. Climate change is considered to increase the risk of pests and diseases

and there are certain factors which make Box more or less vulnerable to infection.

General biosecurity measures set out by the Forestry Commission in their leaflet 'Biosecurity

– good working practice for those involved in forestry' (2012) should be followed.

Pests are most often transported in soil or organic material, such as plant debris, that can

be carried on footwear or by the wheels of vehicles, and via equipment used for tree work.

There is general guidance about how to disinfect footwear etc – the Chilterns Box Woodland

Project referred to guidance by the Forestry Commission and Food and Environment

Research Agency. Disinfectants based on alcohol at a 70% concentration, such as

Isopropanol/Isopropyl and industrial methylated spirit (ISM), are effective against

Phytophthora and other pathogens. Brand names for such chemicals used in the forestry and

horticultural sectors include Propellar and Cleankill as well as Jeyes Fluid and Jet 5. The

Chilterns Box Woodland Project obtained bottles of isopropanol 70% with spray heads and

tubs for footdips.

When using chemicals, refer to health and safety guidance and follow the COSHH

assessment for any products, e.g. obtain the MSDS form for all chemicals. The Forestry

Commission leaflet 'Biosecurity – good working practice for those involved in forestry' (2012)

provides further guidance on the safe and environmentally-responsible use of chemicals in a

woodland setting.

There are various measures which need to be taken to prevent introduction and spread of

pests and diseases. Using the example of Box blight, the following measures are

recommended.

Prevent introduction and establishment of the fungus

When travelling between sites, disinfect equipment and clothing as a routine practice. This

is good biosecurity policy for any pests and diseases, not just blight.

Inform visitors of biosecurity protocol and provide them with disinfecting equipment.

Be most vigilant when conditions encourage spread of the fungus. For example, avoid

walking amongst Box trees when it is raining or wet and keep Box cut back from rights of

way so that people are less likely to brush against trees and spread the spores.

Forestry Commission (2012)

ibid

7

8

7

Page 32

8

Managing Box woodlands and trees in the countryside

Take note of cases of blight in the local area as this will increase the risk of the disease

reaching your site.

Whilst clipping of Box is not associated with trees in a countryside setting, it is possible for

box to otherwise develop a dense growth that encourages fungal infections due to limited

air and light. For example, Box cut back alongside access routes can incidentally take on

the form of a thick hedge whilst thick Box clumps at the bottom of slopes in the Chilterns

can also be damp. Where growth is dense, it is important to thin out branches on a tree and

potentially remove entire trees in amongst dense clumps of Box in order to encourage

ventilation and reduce infection risks.

Preventing spread of the

fungus

The Forestry Commission adopt

the slogan 'Clean in, clean out'.

Whether a site is known to be

infected or not, it is good

practice to disinfect before you

enter a site and disinfect before

you leave. People who travel

around the countryside including

foresters, wildlife recorders and

hired contractors are prime

vectors for pathogens.

Carry out management of Box in

dry conditions.

Should an infection occur,

minimise movements in and out

of the infected area. If possible,

the area should be fenced to prevent animal movements.

Shake off any equipment such as clothing, tarpaulins etc within the infected area to avoid

stray leaves, twigs etc being transported into unaffected areas.

Plan activities so that the higher risk activities and areas are the last to be carried out. This

reduces the risk of spreading the disease to other areas.

Be most vigilant when conditions encourage spread of the fungus. For example, avoid

walking amongst Box trees when it is raining or wet and keep Box cut back from rights of

way so that people are less likely to brush against trees and spread the spores.

Tackling an infection

Address the infection as soon as it is observed. The fungus spreads easily and the disease

cycle is quick in the right conditions and publicly accessible sites are particularly vulnerable

to spread. It is easier and cheaper to deal with a small rather than large area of infection.

Close off access routes in and out of the infected area where possible. Fence off the

infected area to prevent animal movements where possible.

Require all people and equipment moving in and out of the infected area to disinfect their

clothing and equipment. Provide the disinfecting equipment and guidance (e.g. notices) to

ensure people are equipped.

Pests and diseases can be dispersed along access routes, with people, animals and vehicles being vectors. Defoliation of Box trees is evident along this path in the Chilterns.

Page 33

Carry out management under dry conditions.

The amount of plant material to be removed will

depend upon circumstance. In some situations,

such as a garden setting or where there are very

few Box trees or in relation to a 'specimen' tree,

it will be desirable to minimise how much of a

tree is removed. The minimum is to remove

infected parts and to remove fallen leaf litter

and topsoil surrounding the tree. In a large Box

population, it may be wise to remove the entire

tree not just the infected parts since this will

increase the likelihood of destroying the fungus

and the loss of one or a few trees will have little

impact in a large Box woodland.

Remove infected material or, more preferably,

burn all infected plant material on-site where possible. On-site burning reduces the need to

transport infected material which may spread the disease. Rake up leaf litter and burn this

too. When burning infected material, adopt safe fire practices and note that Box burns

readily. To successfully eradicate spores in leaf litter and topsoil, it may be worth

considering the option to do a controlled burn across the ground but expert advice should

be sought in the first instance.

If infected material does need to be transported, designate a vehicle, tarpaulins etc which

will be used for this job and disinfect these vehicles etc afterwards. At Kew Gardens, there

are vehicles used solely for transporting diseased material as a way of containing any

possible infection.

Managing Box woodlands and trees in the countryside Page 34

Before entering and leaving a Box site, boots should be cleaned of dirt using water and a stiff brush. Then a disinfectant applied either in a foot bath or with a spray. Appropriate precautions need to be taken when using chemicals to protect people and the environment.

Managing Box woodlands and trees in the countryside

B.12.1 Case study: Tackling Box blight in the publicly

accessible Wendover Woods

Box grows thickly in some parts of Wendover Woods and it is a

confirmed site for Box blight. Box encroaches onto several access

routes, increasing the risk that the public using the wood are

facilitating the spread of pests and diseases.

In 2014, one bridleway corridor in Wendover Woods was identified

as a high priority area in the developing strategy to address blight

in the woods. Volunteers and foresters were recruited to carry out

this work and received training about biosecurity procedures. The

work area or infected area was identified so that movement in and

out of this area involved disinfecting boots and equipment.

Work was carried out to remove blight-infected sections of Box

trees and any Box overhanging the bridleway. The work was carried

out on a dry day to discourage pests and diseases that thrive in

moist conditions. Arisings were burnt in a nearby fire to eradicate

fungal spores and also to avoid transporting contaminated material

around the site. Tarpaulins were laid on the ground to collect as

much falling debris and branches as possible. Debris was raked up and burnt on the fire.

Care was taken not to allow contaminated material to fall on to the bridleway as there was a

risk that it would be transported into the wider area by passage of people, animals or

vehicles.

B.12.2 Yellowing leaves

Yellow, white or creamy discolouration of the tips or outer edges of leaves can be a sign of

stress, often giving the appearance of variegated Box. If it is stress-related, discolouration

will disappear once favourable conditions return.

Batdorf (2003) has observed that yellowing of lower or interior leaves is a symptom of

nitrogen deficiency. Yellowing is most pronounced on the older, interior leaves and, if the

deficiency becomes acute, the leaves become smaller and thinner and turn quite bronze in

winter.

In wet conditions, yellowing can also be a sign of infection of the roots by Phytophthora

fungus. See separate section on Phytophthora for details.

B.12.3 Copper brown leaves

Lack of nutrients and very cold winds or prolonged periods of frost and ice causes browning

of the leaves. A resilient plant will recover with green leaves in improved conditions.

A blight-afflicted Box tree adjacent to a bridleway in Wendover Woods is cut down. A fire was set up nearby to avoid moving infected material into the wider area. Tarpaulins were laid over the bridleway to collect falling material.

Page 35

Managing Box woodlands and trees in the countryside

B.12.4 Box blight

Box blight is a fungal disease. There are two pathogens which cause box blight: Volutella

buxi (sometimes known as leaf and twig blight) and Cylindrocladium buxicola.

Cylindrocladium was identified some years after Volutella and it appears to cause more

damage than Volutella. Plants attacked by Cylindrocladium are also often infected by

Volutella.

Cylindrocladium buxicola

Cylindrocladium buxicola is a micro-fungus that can sometimes be seen as a grey fungus on

the underside of leaves. A very high humidity is required for fungal spores to germinate and

the spores can remain viable on decomposing leaf material, waiting for the right conditions,

for at least 22 months if not years. The fungus can grow below 10C and the optimum

temperature is 25C.

Primary infection is short range from sticky spores which are airborne or splash (water)

dispersed. Secondary infection is from infected leaves. If humidity levels are high, spores

germinate within 3 hours of

infection and they

penetrate through cuticles.

Leaf spots can appear

within 3 days. Dark brown

spots enlarge and coalesce

in humid conditions,

leading on to defoliation.

The infection rapidly

moves into stem tissue so

that there is death of

smaller branches. Over a

few weeks, black streaks,

appear on the bark. This

disease can defoliate a

mature plant in weeks

(Batdorf 2003).

Page 36

Box trees at Box Hill, Surrey, present the typical sign of blight - defoliated lower branches. Moist, poorly ventilated conditions, as found amongst densely growing Box and in leaf litter, encourages spore germination.

Cylindrocladium buxicola is the more damaging of the two blight fungi. It causes defoliation, black streaks on stems and ultimately die-back. All infections should be taken seriously.

Dark spots on leaves are a sign of blight. In wet conditions, the spore masses of the fungi can be seen on the underside – white for C. buxicola, as shown here, and pink for V.buxi.

Managing Box woodlands and trees in the countryside

Volutella buxi

Volutella has been known for a long time, although it has been little studied. Branches

become thin and weak, making them susceptible to breakage by snow and ice (Batdorf

2003). In moist weather, Volutella forms a 'mass of colourful and distinctive creamy and

light pink to orange dust or fuzz-like growth' that is visible to the naked eye on the

underside of leaves and on branches. This is observed in the densest parts of the plant and

cannot be seen in dry conditions so can be overlooked.

The fungus thrives in the centre of the plant and early infection will usually cause the soft

tissue of the current year's growth to discolour black. If the plant is weak, early

discolouration will also extend into the previous year's growth and create a stem canker.

Cankers appear like a depressed scar in the

bark/stem and there is wilting and death to

the outer parts of the branch beyond the

canker. As the disease progresses, the outer

leaves discolour, changing to a dark brown

and then tan colour. The final stage sees

defoliation of entire branches and then

death of the branches.

Batdorf (2003) states that Volutella growth

and development is particularly severe in

periods of high humidity.

B.12.5 Rusts

According to the RHS, rusts are amongst the

most common fungal diseases affecting

plants and it was frequently observed in the

Chilterns as raised dark spots on Box leaves.

Heavy infection can often, but not always,

reduce plant vigour and in extreme cases,

can kill the plant. It can probably be

tolerated in the countryside but it needs to

be managed when propagating Box, e.g.

removing affected leaves.

B.12.6 Macrophoma leaf spot

Leaf spot is a fungal disease, with water being the

means of dispersal and movement. It is

saprophytic only so arises when Box is dying from

other diseases, winter injury or other stress. The

fruiting bodies appear as raised black spots on the

Box leaves which are often light green or more

commonly tan-coloured. These spots first appear

on older leaves inside the centre of the plant and

progresses to affect younger leaves. Ultimately,

there is defoliation – entire branches can die in

only a few weeks with a heavy infestation.

Thinning will deter Macrophoma and removal of

affected branches can save the plant.

Page 37

Rust is identified by leaf spots that develop into raised pustules commonly found on the underside of Box leaves. It is not considered a concern in the countryside.

Being saprophytic, leaf spot is a sign of a declining Box tree. Box leaves go a distinctive tan colour.

Managing Box woodlands and trees in the countryside

B.12.7 Phytophthora

Only one of the 40 or so Phytophthora species affects Box – Phytophthora parasitica. It is a

soil-borne fungus which moves in a water film. The fungus damages the roots of Box

growing in wet or poorly drained soils, preventing nutrient and water transport to the

plant. Root loss leads to yellowing of the leaves which then turn a bright straw colour and

remain attached to the twigs. This may happen to one branch or several or throughout the

entire tree. Batdorf (2003) states that shrubs infected by Phytophthora 'seldom survive'.

The symptoms, apart from yellowing leaves, include roots and stems with vascular tissue

that has turned a dark brownish-black colour. The bark at the ground level will be decayed,

and so easy to remove.

B.12.8 Nematodes

Nematodes, where present, are small eel-like worms which live in soil and feed on Box

roots. The first visible signs are wilting, stunting and yellowing or bronzing of the foliage.

Leaves may shed prematurely so that branches support few leaves.

B.12.9 Box tree caterpillar

The Royal Horticultural Society reported in 2014 that

cases of the Box tree caterpillar, Diaphania

perspectalis (synonym Glyphodes perspectalis), have

been increasing in number so that it now appears to

be 'established' in South East England. Infected

plants were found near the Chilterns in Stoke Poges,

Buckinghamshire, in 2014. The caterpillar was first

reported in Europe in 2007 in consignment of Box

plants shipped from China to Germany and it was

then found in Surrey and Sussex, England in 2008.

It breeds two to three generations every season

between May and September and adult moths can

spread 5 to 10km a year. The adult moth with semi-

transparent white wings lays eggs in the inner

branches of the plant and the caterpillars emerge to

eat the leaves and create a sticky web. The

caterpillars can grow to 4cm in length. Infestations

are difficult to spot before significant damage is

already done.

It can be controlled by pesticides.

Appleby (2014)

ibid

FERA (undated)

ibid

Page 38

10

11

12

9

Box tree caterpillars are a new arrival to the UK. They eat Box leaves underneath webbing. This is distinctive since Box is not usually damaged by caterpillars.

Box tree moths have a wingspan of 4cm. It is not yet known what distances they travel.

9

10

11

12

Managing Box woodlands and trees in the countryside

B.12.10 Psyllid moth

This insect, also known as Box sucker, causes a curling

or crumpling of leaves, particularly leaves at the tips of

branches. In a garden setting, this is considered

unattractive but in a countryside setting it can be

tolerated and does not appear to noticeably

disadvantage a Box plant.

B.12.11 Animals affecting Box

Box is toxic to livestock, more so than humans. In the

Chilterns, browsing of Box was not observed to be a

significant issue. At several sites grazed by livestock or

frequented by deer and rabbits, Box was left untouched

whilst other plants were grazed/browsed. In the one instance where nursery-grown Box

plants were planted out as a small plantation in the Chilterns on the Wormsley Estate,

Oxfordshire, deer were noted to pluck out a handful of plants planted alongside an

established deer path to then toss them aside.

Sheep and cattle were observed to cause damage to Box trees where they used Box to

shelter, e.g. Crowsley, Ashridge. Bark damage was evident to lower branches and exposed

roots. Localised changes to soil chemistry and ground disturbance caused by livestock are

also likely to have contributed to the prevalence of plants such as stinging nettle and elder.

Burrowing animals are associated with clumps of Box, in some cases undermining roots and

causing physical damage by passing through Box. However, Box can adapt through layering

and suckering.

There have also been instances of damage in the Chilterns where the cause has not been

confidently identified.

Burrows amongst the Box clumps at Aldbury Nowers. Whilst this may not be ideal for the Box tree, the tree persists.

Damage to bark observed at a golf club near Wendover. It has not been possible to determine the cause but current opinion suggests woodpecker or Edible dormouse.

Page 39

A sap-sucking insect sometimes known as Box sucker causes cupping of leaves at the tips of branches. This damage can be tolerated in the countryside.

Managing Box woodlands and trees in the countryside

B.12.12 Climbing plants – ivy, wild clematis

At several Chiltern sites, wild clematis is an expected associate of Box on chalk soils. In

some cases, the clematis is large and heavy. Should there be a desire to conserve a

specimen Box tree or secure timber, it would be advisable to carry out targetted removal of

heavy growth of clematis.

The same can be advised for ivy and bramble.

Page 40

Chiltern Society volunteers at Wendover Woods. From left to right: Glynis Pellat, Richard Bowgen, Maggie Bowgen, David Corfield, Jean Bluck, and Brian Pellat.

Huw Crompton, consultant working with the Wormsley Estate

B.13 Credits to volunteers and others

Holly Cowan and Chris Trimmer, National Trust Plant Conservation Centre

Managing Box woodlands and trees in the countryside

Dorothy Cartright and Sean Reid at National Trust Ickworth, Suffolk

Page 41

Numerous people and organisations made this publication possible. In addition to those

mentioned on previous pages, these photos show other key individuals.

B.14 References and further reading

References

Appleby, M. (2014) RHS warns on box tree caterpillar now established in UK. The

Independent newspaper. 17th June 2014.

Batdorf, L. (2003) Caring for Box. Rye: Sage Press

Batdorf, L. (1997) Boxwood Handbook: A Practical Guide to Knowing and Growing Boxwood.

1st ed revised. St Louis: Messenger Printing Company. Publication for the American Boxwood

Society.

Berry, P., Onishi, Y. and Peterson, J. (undated) Understanding the implications of climate

change for woodland biodiversity and community functioning. Forestry Commission.

FERA, (undated) Plant Pest Factsheet – Box tree caterpillar.

Forestry Commission (2012) Biosecurity – good working practice for those involved in

forestry.

Morecroft, M. and Speakman, L (eds.) (2013).Terrestrial Biodiversity Climate Change

Impacts Summary Report. Living With Environmental Change.

Porley, R. and Hodgetts, N. (2005) New Naturalist: Mosses and liverworts

Additional useful reading

Batdorf, L. (2004) Boxwood: An Illustrated Encyclopedia. American Boxwood Society.

English Nature (2000) Veteran Trees: A guide to good management.

Kew Royal Botanic Gardens (March 2014) UK National Tree Seed Project: Seed Collecting

Manual.

Useful websites

Chilterns Box Woodland Project www.chilternsaonb.org/box

Ancient Tree Hunt www.ancient-tree-hunt.org.uk

Arboricultural Association www.trees.org.uk

Association of Woodturners of Great Britain www.awgb.co.uk

Chilterns AONB www.chilternsaonb.org

Chiltern Woodlands Project www.chilternsaonb.org/woodlands-project

Chris Daunt, woodblock maker www.chrisdaunt.com

European Boxwood and Topiary Society www.ebts.org

Forestry Commission www.forestry.gov.uk

Forestry Commission - biosecurity www.forestry.gov.uk/biosecurity

Millennium Seed Bank www.kew.org/science-conservation/collections/millennium-seed-bank

Natural England - information about Sites of Special Scientific Interest

https://designatedsites.naturalengland.org.uk/SiteSearch.aspx

Plant Heritage - Buxus national collections www.nccpg.com

Royal Horticultural Society www.rhs.org.uk

Tree Council www.treecouncil.org.uk

Woodland Trust www.woodlandtrust.org.uk

Managing Box woodlands and trees in the countryside Page 42

Images © Sarah Wright, Chilterns Conservation Board unless otherwise stated.

Front cover:

Top middle image - © Chris Smith, www.chrissmithphotography.org.uk

Top far right image - © RHS, Horticultural Science

Back cover:

Top middle and far right image - © Chris Smith, www.chrissmithphotography.org.uk

Page 1 - © John Morris, Chiltern Woodlands Project

Pages 2, 3, 15, 16, 18, 30 (bottom image), 33 (bottom image) and 35 - © Chris Smith, www.chrissmithphotography.org.uk

Page 28 - © Chris Daunt, www.chrisdaunt.com

Page 36 (top left image) - © RHS

Page 36 (top right image) - © RHS, Horticultural Science

Page 37 (top image) - © RHS, Horticultural Science

Page 37 (bottom image) - © RHS / Geoff Denton

Page 38 - © RHS / Carol Sheppard

Page 39 (top image) - © RHS / P. Becker

www.chilternsaonb.org/box

Chilterns BoxWoodland Project