a guide to managing deadwood in forestry commission forests...the nation’s woods and forests...
TRANSCRIPT
A guide to
managing deadwood
in Forestry Commission
forests
B r i n g i n g f o r e s t s a l i v e !
Forest Enterprise is an agency of the Forestry Commission
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The nation’s woods and forests managed by Forest Enterpriseare currently undergoing a massive transformation. Nativewoodlands are being restored and expanded whilst the largepost-war forests, established as predominantly even-agedconifer plantation, are being redesigned. This involvesdiversification of age classes through planned, sequentialfelling of coupes followed by restocking with a greater rangeof species including a higher proportion of broadleaves. Somestands of timber will be managed using silvicultural systemswhich avoid clear felling and utilise natural regeneration.Areas will be left unplanted as important open habitats to linkkey sites and encourage wildlife to move through the forestlandscape.
Forest Enterprise has recognised the importance of such‘macro’ landscape scale changes to forest structure.Increasingly our managers are turning to the equallyimportant ‘midi’ and ‘micro’ scale aspects of managementwhich will benefit forest ecosystems and hence biodiversity.One such activity is the imaginative creation and appropriatemanagement of deadwood. Historically, managers removeddeadwood as a hygiene measure to protect the timberresource from what were perceived to be dangerous threatsfrom insect and fungal attack. This has resulted in levels ofdeadwood in British woodland which are too low forsustaining populations of many woodland species of keyconservation importance. Forest Enterprise is committed torectifying this biodiversity deficiency. This guide is primarilyintended to help our staff – managers and planners, as well asfrontline wildlife rangers and machine operators – play theirpart in increasing the volume of beneficial deadwood inForestry Commission forests. However, this guide should alsoprovide valuable insight into deadwood management forother forest managers, our stakeholders, students and all withan interest in life in the deadwood.
Alan W Stevenson
Head of Environment and Communications,Forest Enterprise
Text: Jonathan Humphrey, Alan Stevenson, PhilWhitfield, Janet SwailesIllustrations: Janet SwailesDesign: Melville Design Associates
ContentsIntroduction 3
Native pinewoods and long established pine plantations in the Scottish Highlands 6
Upland broadleaved native woodland in the north and west of Britain 8
Lowland broadleaved woodland in the south and east of Britain 10
20th Century conifer plantations 12
Native riparian woods 14
Planning 15
Operational Management 16
Acknowledgements 17
References and Further Reading 17
Glossary 18
Foreword
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Dead and dying trees play a key role in thefunctioning and productivity of forestecosystems through effects on biodiversity,carbon storage, soil nutrient cycling, energyflows, hydrological processes, and naturalregeneration of trees. Recognition of the valueof deadwood for biodiversity (Ratcliffe, 1993)has led to the development of standards andguidelines for managed forests, which are in theprocess of being implemented (e.g. Anon, 2000a;Anon, 1998; Hodge and Peterken, 1998; Kirby etal., 1998; Ferris-Kaan et al., 1993).
The purpose of this guide is to:• Inspire those who are required to
implement current deadwood guidelinesat both the forest planning andoperational levels;
• Illustrate how deadwood habitats canbest be created and enhanced withindifferent types of managed forest;
• Help with the production of localdeadwood plans;
• Encourage all those who have an interestin the management of deadwood to makethe best of opportunities when they ariseand to develop a long-term perspective;
• Support Forest Enterprise in its aim toundertake sustainable forest managementto the UKWAS standard and ensure thatits wood products carry the FSC greenlabel.
on the structure and dynamics of our managedforests including the provision of better habitatfor deadwood species.
Scope of the guideThis guide is focused primarily on managedconifer and broadleaved forests (both of plantedand semi-natural origin) where there is scope forimproving deadwood habitats to benefit bothgeneralist and specialist saproxylic species. The guidance comprises this booklet and theaccompanying poster tucked into the rear cover.The idealised forest landscape on the front ofthe poster is divided into the main semi-naturalwoodland and wood pasture types to the left ofthe river and the main planted forests types onthe right. Both planted and semi-natural typesare divided broadly into upland/lowlandbroadleaved/conifer types following the UKBiodiversity Action Plan woodland categories(Anon, 1995). The main deadwood featureswithin each woodland type are illustrated anddescribed, showing how the occurrence ofdeadwood in semi-natural woods can be used asa guide for deadwood management within theplanted forests. The focus is primarily at theforest and habitat scales, with no particularemphasis given to rare species, or species with avery restricted distribution unless these help tohighlight some general principles. Uncommonwords and terms are described in the Glossary(page 18). Guidelines for special sites such asancient parkland and wood pasture with veterantrees have been adequately covered elsewhere(Read, 1999; Harding and Rose, 1986) and arenot included specifically in this guide, althoughsome of the principles are adopted. The guidancehere should be considered alongside guidancefor other aspects of biodiversity and within thecontext of other management priorities such astimber, recreation and public safety (see Anon,2000b; Bell, 1998; Anon, 1992).
Introduction
A g u i d e t o m a n a g i n g d e a d w o o d i n F o r e s t r y C o m m i s s i o n f o r e s t s
Working with nature: a futurevisionIn North America and Scandinavia the principleof basing sustainable management ofcommercial forests on the dynamics of naturalforest types is well established, and the provisionof deadwood is seen as an integral part of standmanagement approaches based on naturaldisturbance regimes. In Britain, we are still someway from adopting this approach. Our remainingancient and semi-natural woodlands have beenhighly modified over several millennia and donot represent adequate examples of naturalforest dynamics. Nevertheless on the best sites,we can still see the imprint of past naturalnessin the remaining habitats and species, and thesecan provide some guidance as to what to createin our managed forests. The vision is to workwith natural processes such as wind, dieback anddecay, allowing these to have a greater influence
Dead and dying trees play a vital role in maintaining biodiversity within forestecosystems. In natural forests, decaying wood provides important habitat for small
vertebrates, invertebrates, cavity nesting birds, and a host of lichens, bryophytes, andfungi. Deadwood has been routinely removed from British forests and woodlands forcenturies, resulting in a much depleted woodland flora and fauna. As part of itsresponsibility for the sustainable management of Britain's publicly-owned forests, theForestry Commission is committed to increasing the amount of deadwood within its estateand has produced this poster - and companion guide - to help its managers and planners,as well as frontline wildlife rangers and machine operators play their part in realisingthis goal. However, the guide should also provide valuable insight into deadwoodmanagement for other forest managers, researchers, teachers and planners.
The poster depicts an idealised set of British forest landscapes separated into semi-naturalwoodland and wood pasture – encompassing the UK Biodiversity Action Plan prioritywoodland habitats – to the left of the river and planted forests on the right. Lowlandwoodlands congregate at the foot of the poster, whilst upland woodlands are found
towards the top. Riparian woodlands provide the connection between all the differentwoodland types - just as they do in nature. The key deadwood features within each
woodland type are illustrated together with captions highlighting opportunitiesfor positive management. There are no prescriptions, set rules or stipulations -
the vision is to both use, and mimic, the natural processes of dieback anddecay to provide better habitat for deadwood species and to let the "life
in the deadwood" flourish.
Native pinewood andlong established pineplantations in theScottish Highlands
1 Actively eroding screeslope generatesdeadwood.
2 Standing dead and dyingpines provide a stablelong-term habitat.
3 Capercaille and ospreyroost in large deadbranches.
4 ‘Bog woodland’ containsstunted veteran juniperand pine - a key species
is a longhorn beetle -Leptura sanguinolenta.
5 Weight of snow and icein canopy breaksbranches.
6 Hoverflies Calicera rufaand sawflies breed increvices on standingdead pine.
7 Crested tits nest in well-decayed pine snags >30cm in diameter.
8 Pine snags provide an important habitat for‘pin-head’ lichensChaenotheca species.
9 Actively eroding riverbanks provide a good
natural supply of fallendeadwood.
10 Logs bridging rivers formaccess routes foranimals and hidingplaces for fish.
11 Seedlings regeneratewithin the deadbranches of fallen pine.
12 The timberman beetleAcanthocinus aedilis isan early colonist of deadfallen pine - a host ofother rare deadwoodbeetles inhabit welldecayed fungal-infectedwood.
13 Stumps have a richlichen flora and providerot holes for the larvaeof the rare hoverflyBlera fallax.
14 Root plates provide asheltered microclimateand allow seedlings toescape browsing.
15 Dead and dying aspenprovides a uniquedeadwood ecosystem.
20th Century coniferplantations
1 Retention withindeveloping stand,combining maturingnative trees, fallen andstanding deadwood.
2 Snags provide raptorperches on clear-fells.
3 Retention on a fellingcoupe, combiningmaturing trees anddeadwood: retentions>30m diameter aremore valuable.
4 Retain cut snags.
5 Partially submergeddeadwood in ponds and
streams provides habitatfor bryophytes and thelarvae of craneflies(Lipsothrix species).
6 Stumps provideimportant niches forlichens (Cladonia species).
7 ‘Continuous cover’stands encourage
structural diversity anddeadwoodaccumulation.
8 Windthrow is animportant source of deadwood and could beleft uncleared in somestands.
Upland nativebroadleaved woodlandin the north and westof Britain
1 Veteran birches providehabitat for moths suchas the Rannoch sprawlerBrachyionchyanubeculosa, and for pinemarten.
2 Birch is a short-livedtree and is a goodsource of ‘instantdeadwood’.
3 Birch rots from theinside creating hollowtubes of deadwoodwhich provide roosts forbats and nest sites forhornets andwoodpeckers; bracketfungi Fomes fomentariusare a distinctive feature.
4 Fallen logs are best leftwhere they fall orstacked in partial shade.
5 Oak deadwood takes along time to decayproviding continuity ofhabitat over hundreds ofyears.
6 Debris dam affects riverflow and streammorphology, creatingvaluable habitatdiversity.
7 Polypody fern growingon large dying brancheson mature oak.
8 Oak heartwood althoughhard and stable isbroken down over timeby fungi such as thebeefsteak fungusFistulina hepatica.
9 Active callousing inresponse to injury ‘seals’in deadwood creatingrot columns withintrunks and branches ofliving trees.
10 Burrs, epicormic shootsand rough barkcomplement deadwoodhabitats.
11 Upland oakwoods oftencontain a high biomassof fallen dead branches.
Lowland nativebroadleaved woodlandin the south and eastof Britain
1 Exit holes left byinsects.
2 Insects and fungidepend on each other -insects breakdown thestructure of deadwood,fungi cause chemicalbreakdown.
3 Rot hole created bypollarding createsdeadwood habitat on aliving tree.
4 Beech deadwoodsupports the widestrange of insect specieswithin lowlandwoodland.
5 Sapling regenerating ona root plate.
6 Cracks and rot holes inveteran holly providefood for tree creepersand nests for redstarts.
7 Below-grounddeadwood provides arich habitat for beetles.
8 Over-mature pollardsbrought carefully backinto management.
9 Pollards with deadbranches left on thetree; branches left onthe ground protect theroot zone fromtrampling.
10 Hawthorn is animportant nectar sourcefor deadwood species atcertain points in theirlife cycle.
11 Decaying pollardcontaining detritus ofleaves, insect and birdfaeces and deadanimals.
12 Willow pollard providesa temporary otter holt.
13 Raptor perch on drybeech snag.
14 Greater-spottedwoodpecker hole.
15 ‘Waterhouse’ log pileleft in dappled shade.
16 Fallen deadwood ismoister than standingdeadwood and rotsfaster.
17 Bats like the noctuleNyctalis noctula roost increvices and feed ondeadwood invertebrates.
18 Loose bark createscavities for centipedesand woodlouse.
19 Squirrel and deerdamage.
20 Chainsaw cuts mimicnatural tears andprovide colonisationroutes for deadwoodspecies.
21 ‘Seeps’ and woundsprovide food forhoverflies, hornets andbutterflies.
22 Large branches removedfor safety.
9 Retain veteran nativetrees and open upsurroundings withinplantations on ancientwoodland sites.
10 Retain large logs(≥20cm diameter) tobenefit bryophytes e.g.the liverwort Nowelliacurvifolia.
11 Retain snags (>2m high)- split with a chainsawto mimic naturalprocesses and improvevalue for hole-nestingbirds.
12 Brash piles providetemporary shelter forinvertebrates.
13 Locate old conifer‘natural reserves’ near tosemi-natural woodland.
14 Clear young denseconifers from riparianwoodland: plan mosaicof open and woodedhabitats retainingdeadwood.
15 Permanent shelter beltsprovide continuity ofdeadwood and wildlife‘corridors’.
16 De-stumping removesbelow ground deadwoodimportant forinvertebrates.
17 Small groups of veteranlarch provide nestingsites for goshawksAccipiter gentilis.
18 Retain snags in standsas they mature.
19 Stump piles (createdafter de-stumping)provide shelter foradders and perches forwoodlark.
20 Various species ofclearwing moths usestumps for egg-laying.
Native riparian woods
1 Native riparianwoodland includingmature and overmaturetrees and deadwood.
2 Alder carr provides agood natural reserveand pollarding canprovide a wetlandsource of deadwood.
3 Veteran trees next tofreshwater provide nestcavities for birds andburrows for fish.
4 Retain rare blackpoplars in lowlandriparian zones.
5 Allow dieback of non-native poplars toprovide nest holes forwillow tit Parusmoutanus; lunar hornetclearwing moth Sesiabembeciformis larvaelive in poplar stumps.
6 Recreation and amenityuse should be plannedto avoid safety problemsfrom deadwood.
7 Nectar-rich plants inglades, rides and forestmargins provide food fordeadwood invertebrates.
8 Large log developed asan informal play andamenity resource.
9 Tree surgery stabilisesdeadwood in publicplaces ensuring publicsafety and long termcontinuity in deadwoodsupply.
Key to Forest Zones
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Native pinewood
Uplandnative
broadleavedwoodland
Nativeriparianwoods
20th Centuryconifer
plantations
Lowland nativebroadleavedwoodland
Design & Interpretative Services, Forest Enterprise, Edinburgh. Crown copyright - Forestry Commission 2001. DIS-841/KP/MDA/3.5M/Feb 02Forest Enterprise is an agency of the Forestry Commission
B r i n g i n g f o r e s t s a l i v e !
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The value of deadwood as ahabitat for wildlifeIn natural temperate and boreal forests, decayingwood provides important habitat for smallvertebrates, invertebrates, fish (wood in watercourses), cavity nesting birds, and a host oflichens and bryophytes, polypores and othersaproxylic fungi. Different species requiredifferent types and quality of deadwood.Important factors include: time since death, size,whether standing or fallen, tree species andstage of decay. In general, larger pieces ofdeadwood have more micro-habitats andsupport more species than small pieces. But thisis not always the case; sometimes a largevolume of small deadwood is just as good as asmall volume of large deadwood particularly forsome fungi. Deadwood habitat also occurs onliving trees in the form of rot holes, dead limbs,decay columns and heartrot, and these featuresall have their own associated flora and fauna. Innatural forests, droughts, storms, insect diseaseand fire are the most important factors whichkill trees and create deadwood. Thesedisturbance factors vary in scale and intensity,leading to a patchy distribution of deadwoodboth at the stand and landscape scales withgreater accumulations near canopy gaps and inold-growth stands. In the UK, substantialaccumulations of deadwood are found only inold-growth forest reserves or in remnant habitatwith old trees such as ancient parkland andwood pasture (Harding and Rose, 1986). A largepercentage of rare and endangered saproxlyicspecies are often restricted to these relicthabitats. Many of these species are poorcolonists with exacting habitat requirementswhich are only found where management hasallowed for continuity of mature trees anddeadwood. On the other hand, more recentresearch has shown that quite considerablegains in biodiversity can be made by increasingvolumes of deadwood in plantations. Thebenefits are most obvious for common andwidespread deadwood species (important inthemselves for ecosystem functioning) but alsosome of the rarer and more exacting species (seeplantation section page 12).
Deadwood in water coursesDeadwood plays a vital role in the functioning ofriver ecosystems by: helping to retain water and
sediments; trapping and facilitating thebreakdown of organic matter into food foraquatic invertebrates, diversifying channels bycreating pools, falls and riffles and improvingphysical habitat structure for fish andinvertebrates. Recent research has shown thatmoderate accumulations of larger deadwood(>10cm in width, >1m in length) in headwaterstreams (channels of up to 10m in width) willbenefit migratory fish populations, and aquaticinvertebrates (see Linstead and Gurnell, 1999).The natural spacing of deadwood accumulations- debris dams - is about the equivalent of 7-10times the channel width. Deadwood is a also afeature of natural bog woodlands, and themargins of ponds, lakes and other waterfeatures.
Strategic priorities for deadwoodCurrent guidance (UKWAS, 2000; Hodge andPeterken, 1998) recommends that a minimum ofleast 3 standing and 3 fallen pieces of deadwoodor at least a volume of 5m3 per ha of pieces>15-20cm diameter should be maintained, onaverage, across the forest area as a whole. Thereare benefits associated with spreading deadwoodgenerally throughout the forest. Recent evidencesuggest that even small amounts of deadwoodcan benefit the more mobile and generalist
saproxylic species. These species assemblagesmake up an important part of the forest system,by playing a role in decomposition processes andacting as a food source for species further upthe food chain. Fortunately, normal managementactivities such as thinning, and leavingharvesting residues on site after clear fellingshould cater for these generalist species, andthere is no need for additional managementguidance. To enhance habitat for more exactingspecies, the provision of deadwood should betargeted where it will provide added value toexisting habitat, expand habitat area andimprove linkage between habitats.
Three principles which determine the potentialvalue of deadwood within a woodland or standof trees are:
• Site history: continuity of mature timberand deadwood habitat over a long period.
• Nature of the surrounding landscape: i.e.adjacency to existing ancient semi-natural woodland and other deadwoodhabitat.
• Past and current management: i.e.whether managed as high forest, coppice,minimal intervention etc. Sites whichhave been unmanaged for over 60 yearscan have high volumes of deadwood -sites which have been repeatedly felledare currently less valuable (although oldcoppice stools can harbour characteristicdeadwood invertebrates).
Table 1 shows a list of woodland types indescending order of importance for the provisionof deadwood habitats. Summary managementstrategies and guidance are included for eachtype. Further guidance on how to assess thepotential value of your wood for deadwood inEngland is given in a companion leafletproduced by the England Native WoodlandPartnership (in prep).
Process of decay in standing and fallen deadwood.
100 years 300 years 400 years 500 years 600 years
1 - 2 years
10 years
75 years
150 years
200 years
Table 1: Strategic approach to identifying priorities for deadwood management (adapted from Hodge and Peterken, 1998)Note: The creation of deadwood habitat poses potential risks to health and safety. Site risk assessments should be carried out prior to undertaking any work.
Woodland type Characteristics Management Strategy Management guidance and suggested benchmark values for deadwood
Ancient semi- Continuity of mature timber Identify and protect key sites, For wood pasture and parklandnatural woodland habitat over a long time-scale. including designated areas • Follow guidance in Read (1999).(ASNW), including e.g. NNRs, SSSIs, SACs etc.wood pastures, History of veteran tree For high forestsparkland, and high management (pollarding). Conserve and enhance • Minimum intervention, mimicking of natural processes throughforests which existing veteran trees and small-scale thinning.support a rich Grazing of pasture reducing deadwood.saproxylic flora and scrub regeneration. • Retain all existing veteran trees and trees with decaying wood,fauna with many Permit natural processes with opening up and pollarding to extend life span.notable species. Low intensity of management a view to achieving natural
in high forests, with effects levels of deadwood within a • Aim for 40-100m3ha-1 of deadwood ≥20cm diameter over aof natural disturbance 100 year time frame. long time scale.evident.
• Identify and retain middle-aged trees (>20% of trees in stand) which might form a future generation of veteran trees - allow crowns to develop (see Forbes and Clarke, 2000 forfurther guidance).
• Injure or kill trees to promote future deadwood supply.
• Retain all cut wood on site preferably scattered on the woodland floor.
• Leave all fallen deadwood where it is to decay naturally.
ASNW (including Low deadwood volumes as Permit surviving natural • Store some coppice to produce high forest coupled with long established a result of continual processes with a view to measures to improve stand structural diversity. (Unless this hassecondary management (e.g. coppice); securing and expanding an adverse effect on species which depend on the open woodland) with low lack of large mature remnant/residual deadwood. conditions of coppice and young growth stands, e.g. the Argentdeadwood volumes deadwood habitat. and Sable moth Rheumaptera hastata).and/or saproxylic Retain sufficient mature diversity. timber habitats to attract • Concentrate provision of deadwood in older stands
colonist species and provide (>120 years).a continuity of deadwoodsupply. • Maintain at least 20-40m3ha-1 of deadwood ≥20cm diameter.
• Retain, open up and pollard any existing veteran trees.
• Identify and retain potential veteran trees or trees with decaying wood (20% of trees in stand).
• Retain 20-40% of all cut wood on site; leave all fallen deadwood if possible.
Plantations on Deadwood volumes may be Secure and enhance existing • Where practical, restore gradually using a continuous coverAncient Woodland high - i.e. vestiges of the deadwood habitat in system which will maintain semi-shaded woodland conditions.Sites (PAWS). previous native stand. conjunction with other
restoration procedures • Open up veteran trees and deadwood gradually by removingShading by conifers poses (see Thompson et al., in non-native trees.a threat to deadwood press).habitat and veteran trees, • Consider killing non-native trees in situ to increase deadwood.especially oak.
• See Thompson et al. in press for more guidance.
Plantations Lack of large mature Concentrate deadwood • Locate natural ‘old-growth’ reserves (>60 years) near existingestablished in the deadwood habitat; high provision within a network of native woodland or within riparian zones; aim to retain 5-10%20th Century. volume of small dimension permanently wooded habitats of mature stems in perpetuity with canopies freed to allow full
deadwood. (natural ‘old-growth’ crown development; aim for 5-10% of stems to be dead or reserves) covering at least 1% contain significant decaying wood features equating to
Lack of native tree species. of the forest area by the end deadwood volumes of approximately 20–40m3ha-1.of the second conifer
Deadwood often heavily rotation. • Consider retaining groups (>30m diameter) of snags, logs andshaded. stumps possibly in association with live stems, native trees
Increase deadwood provision species, small pockets of semi-natural vegetation etc. within generally throughout the felling coupes and in other stands (e.g. stands to be managedforest. under a ‘continous cover’ regime).
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Deadwood within native pinewoods and old pineplantations is an extremely important habitat fora range of different species groups. Historically,management has reduced the amount ofdeadwood in many woods, and typical volumesrange from 30-50m3ha-1 in total for snags andlogs. Records from the least disturbed remnants
suggest that volumes in excess of 100m3 mightbe getting close to a more natural
level.
Snag volumes are generallyhigher than log volumes innative pinewoods. Typically,mature or ‘granny’ trees diein situ, creating the
characteristic stag-headedtrees, bleached white in the sun.
These standing dead pines cantake up to 80 years to rot and provide
stable long-term habitat. Branches drop offover time, and eventually the snag topples overshattering into smaller pieces. More rarely, whole
trees blow over creating larger logs. Thesetend to rot very slowly especially wherethe canopy keeps the trunk free of contact
with the ground in the initial years. Thecanopy can provide someprotection from grazing, and
often patches of tree regenerationcan be seen coming up within the confines
of the crown ‘skeleton’.
Snags, logs, stumps and crevices in veteran pines(and occasionally alder, aspen and birch) provideniches for crustose lichens - the distinctive ‘pin-head’ lichen group (where the fruiting bodies areborne on the ends of small stalks) is acharacteristic community of these habitats. Thebright yellow Chrysothrix lichen community isoften found associated with these pin-headlichens and can be an indicator of their presence.Stumps are also important for lichen species
within the genera Calicium and Cladonia. A realrarity within this group is the scheduled speciesCladonia botrytes the stump lichen.
Deadwood in native pinewoods is very importantfor invertebrates many of which are restricted tothe mature pine forest area in the ScottishHighlands. A range of saproxylic beetles dependon a continuity of supply of large diametersnags and logs, for example the timbermanbeetle Aconthocinus aedilis (left) an earlycolonist of new deadwood. Rot holes in stumpsare important for the larvae of the rare hoverflyBlera fallax. Another hoverfly Callicera rufaprefers rot holes and crevices in standing pine.Recent research has also highlighted the valueof deadwood for birds, such as the crested titParis cristatus which nests in well-decayed snagsand stumps >30cm in diameter. Other speciessuch as wryneck Jynx torquilla nest in oldwoodpecker holes in snags, and capercaillieTetrao urogallus roost in large dead branches.
It is not just pine which yields importantdeadwood. Broadleaves within native pinewoodsuch as birch, willow and aspen also provide keyhabitats. Veteran aspen, for example supports adistinctive saproxylic ecosystem in its own right,a characteristic species being the hoverflyHammerschmidtia ferruginea. Other habitatsinclude bog woodlands where stunted pine, birchand juniper form a distinctive feature andprovide habitat for beetles such as Lepturasanginolenta. Fallen trees are also important instreams, ponds and other water features.
Most native pinewoods are likely to be managedat a low intensity in the future so naturalprocesses of death and decay should ensure theprovision of deadwood habitats. However,opportunities exist to augment the supply ofdeadwood, particularly in long-established pineplantations where stem densities are in theregion of 200-400 per ha. Measures include:
• Injuring and ring barking mature trees(diameters >30cm) or removing crowns.
• Leaving large fallen deadwood and stumps.
• Creating high stumps (minimum of 10 perha in clusters, cut at about 1-3m high) tobenefit hole-nesting birds.
Native pinewoods and long-established pineplantations in the Scottish Highlands
A male Capercaillie in pinewoodundergrowth.
Crested tits depend on deadwoodfor nest sites.
Cladonia botrytes the stump lichen - Simon Davey.
Timberman beetle, Aconthocinus aedilis.
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Native pinewoods and long-established pine plantations in the Scottish Highlands
K E Y T O I L L U S T R A T I O N
1 Actively eroding scree slope generatesdeadwood.
2 Standing dead and dying pines provide astable long-term habitat.
3 Capercaille and osprey roost in large deadbranches.
4 ‘Bog woodland’ contains stunted veteranjuniper and pine - a key species is alonghorn beetle - Leptura sanguinolenta.
5 Weight of snow and ice in canopy breaksbranches.
6 Hoverflies Calicera rufa and sawflies breedin crevices on standing dead pine.
7 Crested tits nest in well-decayed pinesnags >30cm in diameter.
8 Pine snags provide an important habitat for ‘pin-head’ lichensChaenotheca species.
9 Actively eroding river banks provide a goodnatural supply of fallen deadwood.
10 Logs bridging rivers form access routes foranimals and hiding places for fish.
11 Seedlings regenerate within the deadbranches of fallen pine.
12 The timberman beetle Acanthocinus aedilisis an early colonist of dead fallen pine - ahost of other rare deadwood beetles inhabitwell decayed fungal-infected wood.
13 Stumps have a rich lichen flora and providerot holes for the larvae of the rare hoverflyBlera fallax.
14 Root plates provide a shelteredmicroclimate and allow seedlings to escapebrowsing.
15 Dead and dying aspen provides a uniquedeadwood ecosystem.
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This woodland category includes Atlanticoakwoods, birchwoods and mixed ashwoods. Twomain factors affecting the value of deadwoodhabitats which are common to all threewoodland types are: 1) the occurrence of woodpasture; and 2) the east-west change in sitetypes and climatic zones.
One of the distinguishing features of uplandwood pasture appears to be the occurrence ofwidely spaced veteran trees which show somesigns of having been managed on a more or lessformal basis (e.g. pollarding), (Quelch 2000). Theprecise distribution and extent of upland woodpasture in Britain has not yet been determined,although it is probable that the best sites in theuplands for saproxylic species will have a historyof wood pasture management.
Native broadleaved woodland which has beenmanaged historically as high forest or coppice isgenerally lacking in deadwood, although theabsence of management over the past 80-100years in some woods appears to be allowing theaccumulation of logs and snags throughwindthrow. In oakwoods, log volumes typicallybuild up from snapping of large branches. Inbirchwoods, snapping of the main stem is morecommon leaving snags of varying height.
Recent surveys have revealed that in morecontinental climates in the eastern half of thecountry (Scotland in particular), dead oak timbercan support those crustose lichens normallyassociated with Scots pine (see native pinewoodsection). In western oceanic climates, deadwoodbecomes much more important as a substratefor bryophytes. Many ancient woodlandbryophytes need a constant regime of humidityand shade. In the wettest areas, liverworts suchas species of the genus Lejeunea can form weftsover deadwood, cliffs and boulders. Well-decayed (i.e. where the bark has been lost, andthe wood is beginning to break down) fallendeadwood appears to be the most valuablesubstrate for bryophytes. Particularly well-developed bryophyte communities on deadwoodand veteran trees provide important cover forpredatory beetle species such as the caterpillarhunter Dendroxena quadrimaculata.
Birch is not as long-lived as oak, and the onsetof dieback can occur as early as 80-100 years ofage. On an ecological time scale therefore, birchcan provide a form of ‘instant’ deadwood. Birch
Fallen logs provide a rich bryophyte habitatoccasionally colonised by vascular plants such aswood sorrel Oxalis acetosella.
rots from the inside out creating hollow tubes ofdead bark which in turn provide excellentroosting sites for bats. Bracket fungi Fomesfomentarius are also a distinctive feature ofbirch snags. Several moth species need over-mature or veteran birch trees, for example theRannoch sprawler Brachionycha nubeculosa.Priorities for deadwood conservation in uplandnative broadleaved woodlands include:
• Establishing minimal intervention areas toallow natural processes a freer rein.
• Retaining all existing veteran trees and largediameter (≥20cm) deadwood.
• Encouraging the development of veterantrees of different native species.
Upland broadleaved native woodland in thenorth and west of Britain
Pine marten running over a fallen log.
Bracket fungion veteran
birch.
9
K E Y T O I L L U S T R A T I O N
1 Veteran birches provide habitat for mothssuch as the Rannoch sprawlerBrachyionchya nubeculosa, and for pinemarten.
2 Birch is a short-lived tree and is a goodsource of ‘instant deadwood’.
3 Birch rots from the inside creating hollowtubes of deadwood which provide roosts forbats and nest sites for hornets andwoodpeckers; bracket fungi Fomesfomentarius are a distinctive feature.
4 Fallen logs are best left where they fall orstacked in partial shade.
5 Oak deadwood takes a long time to decayproviding continuity of habitat overhundreds of years.
6 Debris dam affects river flow and streammorphology, creating valuable habitatdiversity.
7 Polypody fern growing on large dyingbranches on mature oak.
8 Oak heartwood although hard and stable isbroken down over time by fungi such asthe beefsteak fungus Fistulina hepatica.
9 Active callousing in response to injury‘seals’ in deadwood creating rot columnswithin trunks and branches of living trees.
10 Burrs, epicormic shoots and rough barkcomplement deadwood habitats.
11 Upland oakwoods often contain a highbiomass of fallen dead branches.
Upland broadleaved native woodland in the north and west of Britain
2
4
56
7
10
9
11
8
3
1
10
As with upland semi-natural woodland, lowlandbroadleaved woodland can be roughly dividedinto woods with high saproxylic species interestand those with lower interest. Lowland woodpasture (and parkland) is a key habitat forsaproxylic species, and is characterised by large,open-grown (often pollarded) trees at variousdensities, in a matrix of grazed grassland orheathland. The particular value of lowland woodpasture for saproxylic species is attributable to awide variety of different deadwood habitatsintermingled with nectar-rich flower meadowsand pastures. A number of rare and priorityspecies are listed in the Habitat Action Plan forlowland wood pasture and parkland (UKBiodiversity Group, 1998) including amongstothers, the Moccas beetle Hypebaeus flavipesand the New Forest parmelia Parmelia minarum(a lichen). Guidance on the creation andmanagement of deadwood habitats and veterantrees within lowland wood pasture is covered inRead (1991), (1996) and (1999) and is notaddressed specifically in this section.
In other types of lowland broadleaved woodlandsuch as managed coppice and high forests,deadwood volumes were historically low, butafter droughts and major storms in many woodsin the 1980s and 1990s, volumes increasedmarkedly. This lead to a rapid expansion in therange of some deadwood invertebrates notablybeetles such as Agrilus pannonicus and Platypuscylindrus which are early colonists of freshdeadwood. It is safe to assume therefore that
even in those woods which are quite poorin deadwood, artificially increasingdeadwood habitats could considerablybenefit more mobile elements of the
saproxylic flora and fauna.
Both fallen and standing deadwoodis very important for wood-decaying
fungi, which in turn support a high diversityof invertebrates such as fungus gnats
Mycetophilidae, mycophagous andpredatory beetles. Wood-decaying fungi aremostly not specific to any particular tree species,although oak supports about 20 speciesspecialising on stumps, trunks and branches. Thewell known beefsteak fungus Fistulina hepaticaand dryad’s saddle Polyporus squamosus areimportant colonists of heartwood of living trees.
Decaying wood habitats on living veteran treesare particularly important in lowland
broadleaved woodland. Crevices and rot holes fillwith detritus providing habitat for a huge rangeof invertebrates such as centipedes, scarcebeetles (e.g. the lesser stag beetle Dorcusparallelipipedus) and wood lice. Theseinvertebrates in turn provide food for birds suchas the tree creeper Certhia familiaris and redstartPheonicurus phoenicurus. Bats such as thenoctule Nyctalus noctula are almost completelydependant on holes in dead trees for roost sites.Wounds and seepages (sap plus rainwater)provide feeding sites for hoverflies, hornets andbutterflies. Deadwood is particularly importantnear glades and edges where open-structuredflowers such as the umbellifers and hawthornsare of great importance as food sources foradults of insects whose larvae develop indeadwood.
Key management priorities in lowlandbroadleaved woodlands include:
• Setting aside areas to foster development ofold-growth conditions, especially newveteran trees.
• Pollarding existing veteran trees, creatingwounds, crevices - cuts created by chainsawcan ‘mimic’ natural tears providingcolonisation sites for deadwood species(although care should be taken not todamage natural crevices).
• Dead limbs can be as important as trunks forsaproxylics, especially in beech - theseshould be left where fallen unless there is asignificant risk to public safety; deadbranches can also protect the sensitiverooting zone around veteran trees.
• Leaving fallen deadwood where it falls if atall possible. If deadwood has to be movedthen it should be moved as short a distanceas possible, preferably into dappled shadenear rides or glades and near otherdeadwood, keeping it in contact with theground. Piles of smaller logs are usuallymore valuable if lashed together or madeinto a ‘Waterhouse’ pile (see Read, 1999 fordetails).
Lowland broadleaved woodland in the southand east of Britain
Top: Treecreepernests in
snags.
Dryad’ssaddle on
beechlog.
The stag beetle Lucanus cervus lives in the roots ofdeciduous tree stumps.
Woodlice Porcellio scaber andother species live under fallendeadwood.
11
K E Y T O I L L U S T R A T I O N
1 Exit holes left by insects.
2 Insects and fungi depend on each other -insects breakdown the structure ofdeadwood, fungi cause chemicalbreakdown.
3 Rot hole created by pollarding createsdeadwood habitat on a living tree.
4 Beech deadwood supports the widest rangeof insect species within lowland woodland.
5 Sapling regenerating on a root plate.
6 Cracks and rot holes in veteran hollyprovide food for tree creepers and nests forredstarts.
7 Below-ground deadwood provides a richhabitat for beetles.
8 Over-mature pollards brought carefullyback into management.
9 Pollards with dead branches left on thetree; branches left on the ground protectthe root zone from trampling.
10 Hawthorn is an important nectar source fordeadwood species at certain points in theirlife cycle.
11 Decaying pollard containing detritus ofleaves, insect and bird faeces and deadanimals.
12 Willow pollard provides a temporary otterholt.
13 Raptor perch on dry beech snag.
14 Greater-spotted woodpecker hole.
15 ‘Waterhouse’ log pile left in dappled shade.
16 Fallen deadwood is moister than standingdeadwood and rots faster.
17 Bats like the noctule Nyctalis noctula roostin crevices and feed on deadwoodinvertebrates.
18 Loose bark creates cavities for centipedesand woodlouse.
19 Squirrel and deer damage.
20 Chainsaw cuts mimic natural tears andprovide colonisation routes for deadwoodspecies.
21 ‘Seeps’ and wounds provide food forhoverflies, hornets and butterflies.
22 Large branches removed for safety.
Lowland broadleaved woodland in the south and east of Britain
12
3
4
5
12
13
14
15
18
1922
17
20
16
9
1110
8
6
7
21
12
This section focuses primarily on pine and spruceplantations, but the guidance is relevant to alltypes of upland and lowland conifer plantationsestablished in the 20th Century. There is somevalue in spreading deadwood around the forestas whole (see strategy Table 1), but the quality ofdeadwood habitats is increased most effectivelyby focusing on a network of permanentlywooded ‘old-growth’ reserves (Table 1).
Value of deadwood in old-growth naturalreserves
These reserves can provide a semblance of old-growth habitat conditions, including large trees,structural diversity and deadwood. Coniferdeadwood within these reserves can havesignificant value as a habitat for lower plants,fungi and invertebrates (Ferris and Humphrey inpress). On the wetter site types in the north andwest, large, well rotted logs (≥20cm diameter)within semi-shaded spruce stands provide animportant habitat for bryophytes, mimicking ineffect the value of this deadwood type inAtlantic oak - birchwoods. The Schedule 8species green shield moss Buxbaumia viridis ispart of this species group and is found on sprucelogs in only a few sites in northern Scotland. Incontrast to bryophytes, lichens prefer lessshaded conditions and fare better in open standson snags and stumps (particularly Scots pine).Again larger diameter material is more valuable,but not quite as well rotted as the bryophytelogs. Conifer deadwood (>10cm diameter) instreams and rivers can also add valuable habitat
structure such as‘debris dams’ which actas traps for leaf litterand other organicmatter.
Windthrow is a source ofdeadwood in uplandspruce.
Increasing fallen deadwood and stump volumesto 20–40m3ha-1 will benefit wood-decayingfungi, particularly in lowland plantations. Wooddecay fungi have an important relationship withdeadwood invertebrates. To be able to utilisedeadwood, wood-boring insects require woodinfected by fungi as they lack enzymes to breakdown and digest uninfected wood. Thecombination of insects, fungi and rain producewater filled rot holes which provide breedingplaces for numerous flies and beetles; other
invertebrates feed directly onfungi (see lowland broadleavedwoodland section). Upturned rootplates and large logs are also important prey‘plucking’ sites for goshawks Accipiter gentilis.
Location of old-growth natural reserves
The location of these reserves is best consideredat the landscape scale. Research suggests thatthe type of biodiversity developing in recentplantations is linked to the amount, and qualityof semi-natural woodland present in thesurrounding landscape. Conifer natural reservesand long-rotation stands should therefore belocated adjacent or near to semi-naturalwoodland fragments, and also ideally in lowerwind risk areas to allow trees to develop to fullbiological maturity. Where there is little or nonative woodland present within the forest, thedefault position would be to locate old-growthreserves in the riparian zone, but within a mosaicof other open habitats and planted broadleaves,so that streams are not overly shaded. Thedesign of these mosaics should not be identicalfor every riparian zone as there is also a need toencourage diversity at the landscape scale.
Size and management of old growth naturalreserves
Old-growth reserves should ideally be 5ha ormore in size to allow interior woodlandconditions to develop, and could be linked toother long-rotation stands to provide additionalbuffering from disturbance. In the long-term,management inputs would be minimal to allownatural processes to generate deadwood. In theshort -term some management may be neededto hasten younger stands in the mature stage(50-60 years) towards the old-growth stage. Asthe stand nears the age where death ordisturbance will begin to break up the structure,variable density thinning can be adapted tohasten this development by opening up gapsand favouring healthy, windfirm stems that canbe expected to survive for at least another 50-100 years. Any dead or dying trees should be leftin situ (if safety considerations allow) with theaim of sustaining volumes of around 20-40m3ha-1 of large diameter fallen andstanding deadwood over the long-term. Inriparian zones, old growth reserves should belocated within at least 20m wide buffer areas to
Top: Bryophytes beginning to colonise afallen spruce log.
Goshawk with chicks.
provide a continuity of deadwood supply tostream and river. These riparian old growthreserves should be managed by minimalintervention to reduce ground disturbance. (Instreams which are subject to regular majorflooding, there may be a need to securely anchordeadwood to prevent it being washeddownstream where it may damage bridges andother structures).
Felling coupe retentions and mid-successional stands
Harvesting residues on clear-fells, and thinningsin early and mid-successional stands are of valuefor maintaining continuity of habitat forgeneralist deadwood invertebrates (e.g. longhornbeetles), lichens and fungi. Leaving trees ofpoorer form as snags or downed timber willallow these components of the forest ecosystemto be retained through the rotation, particularlyby targeting near old-growth reserves and nativewoodland fragments. Evidence suggests thatdeadwood should be congregated in groupsrather than spread evenly over whole coupes.Patches of windthrow, large trees with poorform, broadleaves and/or Scots pine are desirabletypes of retentions on felling coupes. Aiming forpatches greater than 30m in diameter isdesirable, but not essential. Including patcheswith live retained trees will also help keep thedeadwood moist. Fallen deadwood and coarsebutts can also be stacked under the canopy ofthese patches. Patches make operational sensetoo, leaving the rest of the site clear for standardrestocking.
The value, and hence the priority of havingfelling coupe retentions will vary regionally andby crop types. For example, within the ‘nativepinewood zone’ in the Scottish Highlands, cutstumps on clear-fells are very important forlichens (Cladonia species), especially if allowedto rot in semi-open conditions. Therefore somestumps should be kept open during re-stocking.In lowland plantations such as Thetford, stumpsleft in piles after destumping (necessary for thecontrol of butt rot fungus Heterobasidionannosum) can provide a habitat for addersVipera berus, and perching posts for woodlarksLullula arborea.
20th Century conifer plantations
13
K E Y T O I L L U S T R A T I O N
1 Retention within developing stand,combining maturing native trees, fallen andstanding deadwood.
2 Snags provide raptor perches on clear-fells.
3 Retention on a felling coupe, combiningmaturing trees and deadwood: retentions>30m diameter are more valuable.
4 Retain cut snags.
5 Partially submerged deadwood in pondsand streams provides habitat for bryophytesand the larvae of craneflies (Lipsothrixspecies).
6 Stumps provide important niches forlichens (Cladonia species).
7 ‘Continuous cover’ stands encouragestructural diversity and deadwoodaccumulation.
8 Windthrow is an important source ofdeadwood and could be left uncleared insome stands.
9 Retain veteran native trees and open upsurroundings within plantations on ancientwoodland sites.
10 Retain large logs (≥20cm diameter) tobenefit bryophytes e.g. the liverwortNowellia curvifolia.
11 Retain snags (>2m high) - split with achainsaw to mimic natural processes andimprove value for hole-nesting birds.
12 Brash piles provide temporary shelter forinvertebrates.
13 Locate old conifer ‘natural reserves’ near tosemi-natural woodland.
14 Clear young dense conifers from riparianwoodland: plan mosaic of open and
wooded habitats retaining deadwood.
15 Permanent shelter belts provide continuityof deadwood and wildlife ‘corridors’.
16 De-stumping removes below grounddeadwood important for invertebrates.
17 Small groups of veteran larch providenesting sites for goshawks Accipitergentilis.
18 Retain snags in stands as they mature.
19 Stump piles (created after de-stumping)provide shelter for adders and perches forwoodlark.
20 Various species of clearwing moths usestumps for egg-laying.
20th Century conifer plantations
5
13
14 15
19
10
16
17
18
20
12
9
8
7
3
2
1
6
11
4
14
These are woods found in association with freshwater, beside streams, rivers, lochs and lakes, andare fundamentally important to the health andproductivity of freshwater ecosystems as well ashaving conservation value in their own right.Fallen trees and deadwood play an importantrole in freshwater ecosystems by fostering thedevelopment of ‘debris dams’ which provideshelter for fish and trap organic matter. Wetrotting logs also provide an important substratefor rare cranefly larvae Lipsothrix spp. Veterantrees next to freshwater can provide nest cavitiesfor birds such as goldeneye Bucephala clangula(in northern Britain), and burrows for fish tohide in amongst their roots. On most sites anon-interventionist approach is usually the bestoption for riparian woodlands to minimisedisturbance and damage to stream sides andbanks. However, pollarding can help to increasethe value of old broadleaved trees for deadwoodspecialists; cavities can be created in trees closeto freshwater to provide artificial nest sites. Inlowland riparian woods, dead and dying poplar
Goldeneye nest in cavities in veteran trees
can add significant value, and should be left insitu to provide habitat for willow tit Parusmontanus, lesser spotted woodpeckerDendrocopos minor, and invertebrates such asthe lunar hornet clearwing moth Sesiabembeciformis [A full discussion of the benefitsof woody debris in streams is given in Parrot andMacKenzie (2000)].
Native riparian woods
K E Y T O I L L U S T R A T I O N
1 Native riparian woodland includingmature and overmature trees anddeadwood.
2 Alder carr provides a good naturalreserve and pollarding can provide awetland source of deadwood.
3 Veteran trees next to freshwater providenest cavities for birds and burrows forfish.
4 Retain rare black poplars in lowlandriparian zones.
5 Allow dieback of non-native poplars toprovide nest holes for willow tit Parusmoutanus; lunar hornet clearwing mothSesia bembeciformis larvae live in poplarstumps.
6 Recreation and amenity use should beplanned to avoid safety problems fromdeadwood.
7 Nectar-rich plants in glades, rides andforest margins provide food fordeadwood invertebrates.
8 Large log developed as an informal playand amenity resource.
9 Tree surgery stabilises deadwood inpublic places ensuring public safety andlong term continuity in deadwood supply.
Native riparian woods
1
2
3
4
9
8
7
6
5
15
PlanningHow to go about planning adeadwood strategy at the locallevelIt is important to keep local deadwoodmanagement strategies simple and focused atthe habitat and landscape scales rather thanbeing based solely on individual species. Theover-riding objective will be to initiate lowmaintenance systems which provide biologicalfunctions without excessive management inputsand costs. A separate plan for deadwoodprovision will not often be necessary as this canbe included within other documents relating towildlife and conservation planning, althoughlocations of deadwood reserves should berecorded in design plans. Even if a separatedeadwood plan is not needed, it is worth havinga statement which summarises the approach tothe management of deadwood. This should besimple and straightforward, so that it can beunderstood and used by operational staffperhaps after a modicum of training, andencourages a long-term perspective. It will takelonger than we think to see a real change in theforest. The statement should include a numberof elements, such as: setting out objectives andtargets; identifying priority areas for deadwoodwithin the forest as a whole (i.e. habitats knownto have special value such as SSSI’s), describingoperations within these areas, and outliningplans for monitoring habitat development.
The deadwood management statement/planneeds to include:
1. Objectives such as:
• To ensure that deadwood is providedwhere the biodiversity benefits will begreatest.
• To ensure deadwood provision does notcompromise safety.
• To ensure that the provision of deadwoodis adequately monitored.
2. Some simple policies for the normal workingforest and some for the more special sites(using the information in Table 1).
3. Guidance on how the desired result will beachieved during normal forest operations.Questions that might be asked include:
• What can be done at the site planningstage to identify opportunities?
• How can machine operators be guided tolook for existing deadwood, theopportunities to create more, and forways of grouping deadwood withwindfirm live trees?
• What can be done with coarse low valuelogs or waste and where can these be keptmoist?
• Can anything be achieved during thinningand what safeguards are needed toprotect the resource during felling orrestocking? e.g. avoiding damage toexisting deadwood from harvestingmachinery.
• What ‘on-the job’ training opportunitiescan be identified?
• What type of monitoring is appropriateand affordable?
• How should information be recorded andstored?
What the deadwood statement/plan does notneed to include:
1. Complex stratification of site types beyondwhat is really useful. Keep it simple andcombine similar situations.
2. Overly detailed prescriptions – encouragefield staff to look for opportunities and forspecial sites.
3. Specification of minimum or absolutequantities except in very special cases. Lackof flexibility will lead to either inappropriateresults on sites where few real opportunitiesexist or on others, opportunities beingmissed.
Minimising visual impactConcerns over the visual intrusion of deadwoodare usually over emphasised. Isolated snags cangive a graveyard look but may in any case be oflimited ecological value compared to snags thatare bulked up into small groups with windfirmliving trees, or broadleaf stands. As with any newactivity, there may be a need for low costinterpretation in high access areas, brieflyexplaining what is going on and what thebenefits for wildlife will be. For further guidancesee Bell (1998) or seek advice from a locallandscape architect.
Beech logs provide important habitat for fungi.
16
Health and SafetyThe risk of deadwood falling near people isgenerally low, but in areas which are subject toregular amenity or recreational use and adjacentto public roads, care should be taken to reducerisks by:
• Taking account of deadwood issues duringthe planning and management of timberoperations. For example, an EnvironmentAgency/Scottish Environmental ProtectionAgency licence may be required for work in acontrolled water course.
• Developing a policy and methodology for themanagement of roadside trees (see ForestEnterprise Operational Guidance Note).
• Ensuring that dead limbs and trunks nearrecreational facilities are removed orstabilised. Where such hazards cannot beretained without compromising public safetyonly the minimum work should beundertaken to make it safe.
• Taking opportunities to use interpretation asa management tool to explain the hazardspresented by deadwood.
For the manager, Site Risk Assessment will be thekey in most situations (see Lonsdale, 2000; Read,1999 and Ferris-Kaan et al., 1993 for moreguidance).
Tree healthThere is a balance to be struck between theultimate conservation value of deadwood andthe shorter term risks of providing resources forbark and wood boring insects. Most bark beetleswill not move onto living trees as they can onlyutilize stressed or newly dead trees. Theexceptions are Ips typographus (not yet presentin Britain) and Dendroctonus micans which cankill completely healthy trees. The switch to thecolonisation of living trees only occurs after thebeetles have built up in numbers in stressed orrecently dead trees. This deadwood is onlysuitable for colonisation for a relatively shortperiod (6 months). Once the bark has degradedsufficiently the tree becomes more suitable forcolonisation by other invertebrates and fungalagents that together make up the more benigncomponents of biodiversity. In the case of Ips,the risks are greatest in large forest blocks withcontiguous areas of spruce that may be subjectto windthrow and other environmental stresses.However, as long as Ips and Dendroctonus do
OperationalManagement
not build up a significant population in Britishforests then risks to living trees of leavingincreased amounts of deadwood should beminimal.
Treatment of stumps with ureaRecent research (Westlund and Nohrstedt, 2000)has shown that treatment of stumps with ureato reduce infection by Heterobasidion annosumcan have damaging effects on plants and fungisurrounding the stump and also temporarilyreduces the value of the cut surface of thestump as a substrate for fungi and other woodboring invertebrates. This is only a concern inlong-established pine plantations and nativepinewoods in the Scottish Highlands wherestumps are an important habitat for rare speciessuch as the stump lichen Cladonia botrytes, Blerafellax a pinewood hoverfly, and a host of othercharacteristic species. Stumps within theseforests should not be treated with any fungalretarding chemical.
Monitoring and RecordingMonitoring of deadwood is essential to ensurethat the objectives and targets set out within thedeadwood management plan are being met. Thetype of monitoring system used will depend onthe area of woodland under consideration andthe resources available, but it should besufficiently robust to clearly demonstratechanges over a long time scale. At the forestscale (100ha or more) the locations of key sitessuch as ancient semi-natural woodland, old-growth stands, felling coupe retentions etc.should be recorded, if possible within a GIS. Thiscould be done as part of the forest designplanning process. The sites would be re-mappedevery 5 years with records made of anydeadwood enhancement operations.
It should not be necessary to measure deadwoodacross the whole forest nor in all the key sites. Arepresentative sample (10% of all key sites)measured on a 5-10 year rotation should besufficient to identify broad trends. Ideally,deadwood should be measured, or at leastestimated, quantitatively. The aim would be tosample 5-10% of the area of each stand/key sitefocusing on recording larger material (i.e. mid -diameter ≥ 20cm, length > 0.5m). The lower sizelimit for recording is usually 5cm diameter.
It is recommended that the line interceptmethod (Kirby et al., 1998) is used for estimatingvolumes of fallen deadwood. This involveswalking a line (transect) through the site along aset compass bearing, and counting the numberof logs that intersect this line. Volumes can becalculated by estimating the mid-diameter andlength of each piece of deadwood to the nearest10cm, and placing within a size and a decaycategory. Normally, 10cm diameter size classesare used combined with a decay scale such asthat shown in Table 2.
Table 2: Suggested scale for estimating decaystate of deadwood, from Hunter (1990).
Standing deadwood and stumps can bemeasured in belts 2m wide on each side of thefallen deadwood transects. Only snags andstumps whose centres are within the beltsshould be recorded. As with fallen deadwood,height and diameter at breast height should beestimated for each deadwood item.
For a typical 10ha old-growth reserve, abouttwelve 100m transects would be needed to givea 5% sampling area; more transects would beneeded in larger stands, and fewer in smallerstands. Care should be taken to ensure that thelocation of transects is stratified to encompassvariability in stand conditions across the site.There should also be no bias in the starting pointor orientation of the transects that might justinclude or just avoid a particular item ofdeadwood. Where exceptional accumulations ofdeadwood are encountered (e.g. catastrophicwindthrow) it may be necessary, for safetyreasons, to restart the transect on the other sideof the windthrow and estimate the windthrownvolume from a distance. All transect data shouldbe stored on paper and ideally within anelectronic database to allow comparisonsbetween different sampling periods.
To identify new potential deadwood reserves,quick qualitative estimates of deadwood will benecessary followed up by quantitativeassessments on those sites which are eventuallyselected. Aerial photographs will help identifyareas of windblow, or the index in Table 3 couldbe used during a ground survey. Sites which hadan index of 3 or 4 might be good candidates fordeadwood reserves.
Table 3: Example of index for estimating valueof site or stand in terms of snag/log densities(adapted from Peterken, unpublished). The indexcould also be used for other types of deadwoodsuch as stumps or trees with decay columns, andheartrot etc.
Index Description 1 Bark intact, small branches present2 Bark loose or sloughing off, no
sapwood degradation3 No bark, some sapwood degradation4 No bark, considerable sapwood
degradation5 Sapwood and heartwood degradation
Index Description 1 Small snags/logs only 2 Large snags/logs at low density with
our without small snags/logs 3 Large snags/logs at moderate density
with our without small snags/logs 4 Large snags/logs at high density with
our without small snags/logsSmall = 5-19cm diameter, < 0.5m length/heightLarge = ≥20cm diameter, >0.5m length/heightLow density = 5% or less of total stems per ha (living + dead)Moderate density = 6-10% of total stems per haHigh density = 11% or more of total stems per ha
17
Peter Quelch, Richard Ferris, Keith Kirby, Roger Key,Steven Hendry, Hugh Evans, Jonathan Spencer, GrahamGill, Chris Nixon, Jim Pratt, Jo O’ Hara, Julian Fryer,Emily Ramsey, Wilma Harper, Rod Leslie, David Killerand Fred Currie made valuable comments on earlierversions of this guide and provided additional material.The concept was developed by Alan Stevenson, BobJones and Jonathan Humphrey with contributionsfrom Phil Whitfield and Peter Weston.
Alexander, K., Green, T., and Key, R. (1998). Managingour ancient trees. Tree News Spring 10-13.
Anon (1992). Forest Recreation Guidelines. ForestryCommission, Edinburgh.
Anon (1995). Biodiversity the UK Steering Group Report.Vol 2. Action Plans. London, HMSO.
Anon (1998). The UK Forestry Standard: The UKGovernment’s Approach to Sustainable Forestry. TheForestry Commission, Edinburgh.
Anon (2000a). The UK Woodland Assurance SchemeGuide to Certification. UKWAS Steering Group, c/oForestry Commission, Edinburgh.
Anon, (2000b). Forests & Water Guidelines. ThirdEdition. Forestry Commission, Edinburgh.
Bell, S.J. (1998). Forest design planning: a guide to goodpractice. Forestry Practice Guide. Forestry Commission,Edinburgh.
Currie, F. and Elliot, G. (1997). Forests and birds: a guideto managing forests for rare birds. ForestryCommission, RSPB.
England Native Woodland Partnership (in prep). Theconservation of decaying wood habitats within semi-natural woodland. England Native WoodlandPartnership Information Note.
Ferris, R., and Humphrey, J.W. (in press). Biodiversity inBritain’s forests: results from the Forestry Commission’sBiodiversity Assessment Programme. ForestryCommission Technical Paper.
Ferris-Kaan, R., Lonsdale, D. and Winter, T. (1993). Theconservation management of deadwood in forests.Research Information Note 241. Forestry Commission,Alice Holt.
Forbes, V. and Clarke, A. (2000). Bridging thegeneration gap. Enact 8, 7-9.
Forestry Commission (1994). The management of semi-natural woodlands. Forestry Practice Guides 1-5.Forestry Commission, Edinburgh.
Green, P. and Peterken, G.F. (1997). Variation in theamount of deadwood in the woodlands of the LowerWye Valley, UK in relation to the intensity of management.Forest Ecology and Management 98, 229-238.
Hansen, A.J., Spies, T.A., Swanson, F.J., and Ohmann, J.L.(1991). Conserving biodiversity in managed forests.Lessons from natural forests. Bioscience 41, 292-382.
Harding, P.T. and Rose, F. (1986). Pasture woodland inlowland Britain. Huntingdon, Institute of TerrestrialEcology.
Harmon, M.E., Franklin, J.F., Swanson, J.F., Sollins, P.,Gregory, S.V., Lattin, J.D., Anderson, N.H., Cline, S.P.,Aumen, N.G., Sedell, J.R., Lienkaemper, G.W., Cromack,Jr., K. and Cummins, K.W. (1986). Ecology of coarsewoody debris in temperate ecosystems. Advances inEcological Research 15, 133-302.
Hodge, S.J. and Peterken, G.F. (1998). Deadwood inBritish forests: priorities and a strategy. Forestry 71,99-112.
Hunter, M. L., Jr. (1990). Wildlife, forests and forestry:principals of managing forests for biological diversity.Prentice-Hall, Englewood Cliffs, New Jersey.
Kirby, P. (1992). Habitat management for invertebrates:a practical handbook. JNCC/RSPB.
Kirby, K.J. and Drake, C.M. (eds) (1993). Deadwoodmatters: the ecology and conservation of saproxlyicinvertebrates in Britain. English Nature Science series No.7.
Kirby, K.J., Reid, C.M., Thomas, R.C. and Goldsmith, F.B.(1998). Preliminary estimates of fallen deadwood andstanding dead trees in managed and unmanaged forestsin Britain. Journal of Applied Ecology 35, 148-155.
Linstead, C., and Gurnell. A.M. (1999). Large woodydebris in British headwater streams: physical habitatrole and management guidelines. R&D technical ReportW185. Environment Agency, Swindon.
Lonsdale, D. (2000). Hazards from trees: a general guide.Forestry Commission Practice Guide. ForestryCommission, Edinburgh.
Parrot, J. and MacKenzie, N. (2000). Restoring andmanaging riparian woodland. Scottish Native Woodlands.
Quelch, P.R. (2000). Upland pasture woodlands inScotland. Part I. Scottish Forestry 54, 209-214.
Ratcliffe, P.R. (1993). Biodiversity in Britain’s forests.The Forestry Authority, Edinburgh.
Read, H.J. (ed). (1991). Pollard and veteran treemanagement. Corporation of London.
Read, H.J. (ed). (1996). Pollard and veteran treemanagement II. Corporation of London.
Read, H.J. (1999). Veteran trees: a guide to goodmanagement. English Nature, Peterborough.
Reid, C.M., Foggo, A. and Speight, M. (1996). Deadwoodin the Caledonian pine forest. Forestry 69, 275-279.
Samuelsson, J., Gustafsson, L. and Ingelög, T. (1994).Dying and dead trees - a review of their importance forbiodiversity. Threatened Species Unit, SwedishUniversity of Agricultural Science, Uppsala, 109pp.
Speight, M.C.D. (1989). Saproxylic invertebrates andtheir conservation. Nature and Environment Series No.42 Council of Europe, Strasbourg.
Thompson, R.N., Humphrey, J.W., Harmer, R. and Ferris.R. (in press). The restoration of native woodland onancient woodland sites. Forestry Practice Guide.Forestry Commission, Edinburgh.
UK Biodiversity Steering Group (1998). Lowland woodpasture and parkland: a habitat action plan. In Tranche2 Action Plans Vol II. Terrestrial and freshwaterhabitats. Peterborough: UKBG/English Nature.
Westlund, A. and Nohrstedt. H. O. (2000). Effects ofstump-treatment substances for root rot control onground vegetation and soil properties in a Picea abiesforest in Sweden. Scandinavian Journal of ForestResearch 15, 550 - 560.
Acknowledgements References and Further Reading
Leptura rubra a scarce longhorn beetle.
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Ancient woodland: Woodland which has remaineduncleared since at least AD 1600 in England and Walesand AD 1750 in Scotland.
Bog woodland: Woodland containing a scattered mixof stunted trees, often of considerable age, and openbog vegetation.
Burr: A tumour-like swelling on a tree resulting fromany number of causes, sometimes associated withepicormic (lateral branching from trunk) growth.
Carr: Water-logged woodland often on the edge ofbogs or in other poorly drained locations.
Clearfelling: The cutting down of all trees on an areaof more than 0.25ha.
Conservation Agency: Government agencyresponsible for the protection and conservation of thenatural environment.
Continuous cover: Use of a silvicultural systemwhereby the forest canopy is maintained at one ormore levels without clear felling.
Coppice: A tree or shrub repeatedly cut at, or close to,ground level.
Coppice stool: The part of a coppice which is left aftercutting.
Coppicing: Cutting a coppice.
Crown: Spreading branches and foliage of a tree.
Debris dam: Accumulations of fallen deadwood ofvarious sizes within streams which causes temporarybut incomplete damming of water flow.
Decay columns: Columns of dead and dying woodwithin trees caused by fungal or bacterial infection.
Destumping: Practice of removing stumps after fellingto reduce risk of spreading butt rot fungus to newlyplanted trees.
Felling coupe: An area proposed for felling in oneoperation.
FSC: Forest Stewardship Council.
Granny pine: Veteran native Scots pine tree withwidely spreading branches and large girth.
Habitat Action Plan: Plans within the UK BiodiversityAction Plan which identify actions needed to stabiliseand improve the status of habitats with highconservation value.
Habitat scale: Usually equated with stand scale (0.5 -50ha) but can also include smaller areas depending oncontext.
Heart rot: Decay of inner wood (heartwood) of trees.
High forest: Woodland which is not managed ascoppice or pollards and which may or may not bemanaged for timber.
Landscape scale: Areas greater than 1 km2 - e.g. rivercatchments.
Log: Fallen deadwood.
Long-established woodland: Woodland planted inthe 17th, 18th and 19th centuries; often managedusing a non clear-fell silvicultural system.
Long rotation stands: Stands retained beyond thenormal economic felling age (40-80 years), but whichwill be felled at some time.
Lower plants: Mosses, liverworts, and lichens
Mensuration: Measurement of trees.
Mid-successional stands: Stands which have passedthe establishment phase, but are not ready to be felled;a typical range of ages would be 20-50 years.
Minimal intervention: Relating to stands where thereis negligible management inputs, and practices such asfelling, thinning and restocking do not take place.
Mycophagous: Organisms that feed on fungi.
Native species: Species which are considered to benaturally occurring in the UK.
Native woodland: Woodlands composed of site nativeand locally native tree and shrub species.
Natural disturbance: Disruption to forest stands,vegetation and wildlife by a natural event such asstrong wind, fire or grazing.
Natural regeneration: Trees or shrubs which becomeestablished through the natural processes of seedingand germination.
Natural Reserve: Unmanaged stands set aside toallow natural processes a freer reign and to encouragethe development of structural diversity and deadwoodhabitats.
NNR: National Nature Reserve designated by thecountry conservation agencies.
Old growth: A forest stand which has developed freefrom large-scale disturbance over a long period of time(80-500+ years) and contains large old trees, largefallen and standing deadwood in various states ofdecay, and a wide variation in tree size and spacing.
Open grown: The form of trees grown in the absenceof competition and shading.
Parkland: Area enclosed for keeping deer and/oramenity use.
Plantations on Ancient Woodland Sites (PAWS):Planted woodlands of any type on Ancient Woodlandsites.
Pollard: A tree cut 2-4m above ground level,producing a crop of branches which can be harvestedin subsequent years.
Pollarding: Cutting a pollard.
Polypore: Fungal species within the family Polyporacea- includes bracket and fan fungi which live ondeadwood.
Raptor: A bird of prey which kills with its feet.
Restocking: The practice of replanting after a stand oftrees has been felled.
Restoration: The re-establishment of native trees andnatural processes on planted ancient woodland sites.
Retention: Stand retained beyond normal economicfelling age (40-80 years) which will normally remainunfelled in perpetuity.
Ride: Unplanted strips between stands, used asfirebreaks and access routes.
Riffles: Rapids where the water is shallow andvelocities high enough to keep the bottom clear ofmud and silt.
Ring barking: Complete removal of a section of barkencompassing the full circumference of a tree trunk,done to kill the tree.
Riparian zone: Land immediately surrounding awatercourse.
SAC: Special Area for Conservation designated underthe European Union Habitats and Species Directive1992 (EC directive 92/43).
Saproxylic: Organisms that depend on wood, usuallybut not always dead wood, for some part of their lifecycle.
Schedule 8 species: A species legally protected underSchedule 8 of the Wildlife & Countryside Act 1981. Thismeans that neither the species nor its habitat shouldbe damaged, nor the species collected in the wild.
Semi-natural woodland: Woodland containing nativetrees that were not originally planted.
Silviculture: The management of a stand of trees forpre-defined objectives.
Snag: Standing dead tree.
SSSI: Site of Special Scientific Interest - a designationgiven by the country conservation agencies under theWildlife and Countryside Act 1981.
Staghead: Dead crown of a veteran tree.
Stand: A group of trees of similar age.
Structural diversity: Variability in the structure offorest stands attributable to tree size, shape, densityand distribution.
UK Biodiversity Action Plan: The UK governmentresponse to the Convention on Biological Diversity atRio de Janeiro; includes actions to safeguard keyhabitats and species.
UKWAS: UK Woodland Assurance Scheme.
Urea: Chemical used as a fungal retardant on stumps.
Variable density thinning: A thinning practiceinvolving the removal of trees of varying sizes within astand and at different densities throughout the stand.
Veteran trees: Fully grown trees which have sufferedextensive dieback, with many branches lost or severelyaffected and with substantial heart rot.
‘Waterhouse’ pile: Log pile retained to benefitinvertebrates.
Windfirm: Trees that are unlikely to blow over whenexposed to strong winds.
Windthrow: Partial or complete overturning orbreakage of trees.
Wood pasture: Grazed woodland characterised byopen grown (often pollarded) veteran trees at variousdensities.
Glossary
Further information and usefuladdressesThe Forestry Commission of Great Britain isthe government department responsible fordeveloping and implementing the Government’spolicies of sustainable forest management whichinclude protecting and expanding Britain’sforests and woodlands, and increasing theirvalue to society and the environment. TheForestry Commission has national offices inScotland, Wales and England. Contact theForestry Commission for information on forestryand woodland management, grants and licences.
Forest Enterprise is an Agency of the ForestryCommission responsible for the management offorests and woodlands owned by the nation.Forest Enterprise became a Next Steps ExecutiveAgency on 1 April 1996. Its aims are to deliverthe environmental, financial, social and otheroutputs sought by Ministers and the ForestryCommissioners. Contact Forest Enterprise forinformation on Forestry Commission forests.
Forest Research is an Agency of the ForestryCommission and is the principal organisation inthe UK engaged in forestry and tree relatedresearch. The Agency was launched on 1 April1997 with the purpose of providing research,development, surveys and related services to theforest industry and providing authoritativeadvice in support of the development andimplementation of the Government’s forestrypolicies. Contact Forest Research for scientificadvice relating to forest management.
Forestry Commission231 Corstorphine RoadEdinburgh EH12 7AT Tel: 0131 334 0303Fax: 0131 334 4473E-mail: [email protected]
Forestry Commission (England)National OfficeGreat Eastern House, Tenison RoadCambridge CB1 2DU Tel: 01223 314546Fax: 01223 460699 E-mail: [email protected]
Forestry Commission (Scotland)National Office231 Corstorphine RoadEdinburgh EH12 7ATTel: 0131 334 0303Fax: 0131 314 6152 E-mail: [email protected]
Forestry Commission (Wales)National OfficeVictoria Terrace, AberystwythCeredigion SY23 2DQTel: 01970 625866Fax: 01970 626177E-mail: [email protected]
Forest Enterprise Headquarters231 Corstorphine RoadEdinburgh EH12 7ATTel: 0131 334 0303Fax: 0131 334 4473E-mail: [email protected]
Forest Enterprise WalesVictoria TerraceAberystwyth, Ceredigion SY23 2DQTel: 01970 612367Fax: 01970 625282
Forest Enterprise Scotland (South)55/57 Moffat RoadDumfries DG1 1NPTel: 01387 272440Fax: 01387 251491
Forest Enterprise Scotland (North)1 Highlander WayInverness Retail & Business ParkEast Field WayInverness IV2 7GBTel: 01463 232811Fax: 01463 243846
Forest Enterprise England340 Bristol Business ParkColdharbour LaneBristol BS16 1EJTel: 0117 906 6000Fax: 0117 931 2859
Forest ResearchNorthern Research StationRoslin, Midlothian EH25 9SYTel: 0131 445 2176Fax: 0131 445 7335E-mail: [email protected]
Forest Research Alice Holt LodgeWrecclesham, Surrey GU10 4LHTel: 01420 22255Fax: 01420 23653E-mail: [email protected]
Published by Forest Enterprise – Environment &Communications, Edinburgh.Design concept and print management by Design &Interpretative Services, Forest Enterprise, Edinburgh. Deadwood and landscape llustrations by Janet Swailes.Design and production by Melville Design Associates.
Crown copyright - Forestry Commission 2002. DIS-841/KP/MDA/3.5M/Feb 02.
Forest Enterprise is an agency of the Forestry Commission
www.forestry.gov.uk
An agency of the Forestry Commission