MANAGEMENT OF WOODLAND PLANTS IN ATLANTIC BROADLEAVED WOODLAND A CONSERVATION FRAMEWORK. Written by Richard Worrell and Deborah Long

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2 MANAGEMENT OF WOODLAND PLANTS IN ATLANTIC BROADLEAVED WOODLAND A CONSERVATION FRAMEWORK Written by Richard Worrell and Deborah Long Acknowledgements The authors wish to thank: Sandy Coppins, Gordon Rothero, Richard Thompson (Forest Enterprise), Dave Genney (SNH), Lucy Sumsion, Peter Quelch and Carol Crawford for their advice and expert input. Thank you to Sue Nottingham for proofreading and Luke Morton for design. 2

3 Contents 1. Introduction Aims Need for improved management of plant communities The Important Plant Area concept 3 2. Atlantic Woodland and its current management Defining Atlantic Woodland Current management of Atlantic Woodland Management for woodland flora 9 3. Guiding principles for woodland management Landscape scale planning Site (woodland) scale management Assessing plant communities and drawing up management prescriptions Management prescriptions Planning issues Grazing control Manipulating the woodland canopy to improve conditions for flora Woodland shrubs and scrub Deadwood Control of invasive exotic plant species Conversion of conifer to native woodland, including PAWS Movement of woodland plants into species poor isolated woodland Integration of management prescriptions Monitoring Support via Scottish Government grant schemes 34 3

4 1. Introduction 1.1 Aims This report describes a conservation management framework for Atlantic woodland based on the Important Plant Area (IPA) concept ( The framework is intended to deliver: 1. Guidance on how to assess the conservation value of woodland flora. 2. Outline management guidance for woodland flora at both local (site) and catchment (habitat network) scales. 3. Means of assisting conservation planning by prioritising the locations where management is required based on habitat network principles. The long term aim is to increase habitat and species resilience through improved habitat quality and the formation and expansion of habitat networks. The need for this work arises because: There is relatively little management guidance aimed specifically at woodland flora, compared with that available for trees, birds, mammals and some invertebrates. There is a need to strengthen landscape scale and habitat network approaches in conservation management to augment current site based approaches. There is a need for conservation organisations to be able to prioritise scarce resources in the face of effectively unlimited demands. The approach described here is designed to dovetail with other available guidance; notably the Forestry Commission Forest Habitat Network approach (Moseley et al. 2005), the Woodland Grazing Toolkit (Sumsion and Pollock 2006), and the Peterken-Worrell management models for Atlantic Oak woodlands (Peterken and Worrell 2005, Quelch 2005). It is intended to be suitable for all organisations involved in woodland conservation and management. Atlantic woodland is one of six priority habitats under Plantlife Scotland s Back From the Brink programme. This report will guide conservation activities undertaken by Plantlife Scotland within the West Coast IPA under Plantlife Scotland s Back From the Brink programme. 1.2 Need for improved management of plant communities Most woodland plans, especially those without designated areas, have limited coverage of woodland flora and little or no consideration of management that might enhance plant communities (other than trees). Management specifically aimed at safeguarding and enhancing woodland plants in Scotland has started to be developed in the last five years (Coultard and Scott 2001, Coppins and Coppins 2005, Moseley et al 2005, Rothero 2005, Thompson 2005, Sumsion and Pollock 2006, Averis and Coppins 1998, Coppins et al. 2008). However, with a few notable exceptions (e.g. Averis and Coppins 1998, Thompson 2005), there is currently little guidance aimed at practitioners (owners, agents, surveyors) that would help in preparing the vegetation sections of woodland plans. This is clearly a deficiency as woodland plans are the main vehicle for delivering improved management and are the means by which owners can access government grants to support conservation work. 4

5 1.3 The Important Plant Area concept In 2007, Plantlife launched a list of 150 Important Plant Areas (IPAs) across the UK (see IPAs are areas of great botanical importance for threatened species, habitats and plant diversity; and their identification and management meets Target 5 of the Global Strategy for Plant Conservation (Plantlife, Kew and JNCC 2002). In the UK, IPAs have been identified where there are exceptional sites holding rare and diverse communities of flowering plants, bryophytes, lichens, stoneworts and algae. Areas qualify if they meet one or more of these internationally agreed criteria (Anderson 2002): 1. They hold significant populations of one or more species that are of global or European conservation concern. 2. They have an exceptionally rich flora in a European context in relation to its biogeographic zone. 3. They are an outstanding example of a habitat type of global or European plant conservation and botanical importance. IPAs can contain a wide range of habitats and species and they are rarely identified on the presence of one type of plant or habitat. IPA boundaries are identified using a two stage process that maps: Core areas of habitat where the qualifying features are present. These can correlate with designated sites (e.g. SSSIs), but also includes all other ecologically suitable areas. They may consist of a single area or several unconnected areas comprising a series of plant sites. Zones of opportunity, into which, if the current land use is appropriate and correct habitat management is carried out, the key species or habitats could expand. These are shown as a series of 1 km buffer zones around the core areas filtered using key predictive environmental variables to identify areas with the greatest potential for expansion. The IPA approach can be used for prioritising conservation work. Firstly sites within IPAs are likely to be of higher priority than similar sites not in IPAs and the most important habitats in the IPAs are identified. Secondly the most important locations and broad types of conservation work required are identified during the IPA mapping process. Priorities for conservation work would usually follow the sequence: 1. Improving the habitat condition of the core areas; 2. Expanding core areas into the zones of opportunity to form larger more robust areas; 3. Linking areas of habitat into larger networks usually by improving the habitat condition of areas of ground between habitat patches (in both core areas and zones of opportunity). Such work to improve habitat networks provides the potential for increasing resilience of plant communities and habitats to a range of impacts, including the effects of climate change. IPAs and Forest Habitat Networks The process of developing IPAs closely mirrors Forest Habitat Networks ( meaning the two approaches are compatible. For example, initial analysis of the West Coast IPA has indicated that the Sunart area IPA for Atlantic 5

6 woodland is similar to the Sunart Forest Habitat Network 1 (see figs 1 and 2). This is important because many of the woodland managers involved with Atlantic woodlands will be familiar with the Forest Habitat Network approach. Figure 1: West Coast Scotland IPA showing the core areas and zones of opportunity. 1 Core Areas and Zones of Opportunity in IPAs are equivalent to habitat and restoration / conversion / expansion zones of Forest Habitat Networks. 6

7 Figure 2: IPA map for Loch Sunart area. Green areas are Zones of Opportunity, other colours are different categories of Core Area. The West Coast Scotland IPA The West Coast Scotland IPA is one of 42 IPAs identified in Scotland. It covers an area of about 800 km 2 stretching from Kinlochbervie in the north, to Tarbert in the south and Glen Coe in the east ( Most sites within this area have been nominated for old sessile oak woodland and montane oceanic heath 2, both habitats that are internationally rare. Some of the best Atlantic woodland sites for oceanic bryophytes and lichens in Europe occur here. It includes 47 core sites, nominated for the rich diversity of bryophytes, lichens and other plants, many of which are internationally important. Subsidiary core sites are identified as ancient woodland with a high diversity of lichens and / or bryophytes and the presence of an indicator species, Plagiochila heterophylla (Fraser and Winterbottom 2008). The main threats to woodland sites are the spread of Rhododendron ponticum, over and under grazing and inappropriate woodland management. Core Areas and Zones of Opportunity Fraser and Winterbottom (2008) identified 47 core sites, according to their rich bryological and lichenological diversity, with additional subsidiary core sites identified from a) the SNH Ancient Woodland Inventory, b) specific sites identified by Averis (2001); and c) sites with Plagiochila heterophylla, an indicator species for Atlantic woodland. Details of the mapping procedure are given in Fraser and Winterbottom (2008). 2 Other habitats included are dune systems, Caledonian pinewoods, blanket bog and freshwater lochs. 7

8 2. Atlantic woodland and its current management 2.1 Defining Atlantic woodland Atlantic woodland is woodland that occurs in highly oceanic climatic conditions close to the Atlantic Ocean. Various definitions have been put forward employing the terms Atlantic, oceanic and hyperoceanic to describe the climate, woodland and plant communities and usually focusing on: Wetness i.e. high annual rainfall, high numbers of wet days, wetness during summer season, low potential water deficit. Little annual temperature variation and low incidence of frost and snow cover. For the purpose of this report all native woodland within the West Coast Scotland IPA is to be considered to be Atlantic (see Figure 1). The botanical defining characteristics of Atlantic woodland centre on the rich bryophyte and lichen communities that are supported in these climatic conditions, that often show gradations with increasing oceanicity even within the Atlantic zone. As a result of the climatic conditions and topography, Atlantic woodlands acquire other characteristics: - high wind speeds result in wind driven disturbance patterns and in coastal areas, dwarfing of trees including salt effects; - steep environmental gradients with proximity to coast and increasing elevation lead to strong landscape-scale variation; - the soils show clear patterns of leaching and flushing according to topographic position, with corresponding variation in woodland and plant communities; - the often highly incised topography, including ravines and raised coastlines, leads to unusual habitats and habitat network patterns. At a global scale Atlantic woodlands are best considered as part of the coastal temperate rainforest biome, which has a very restricted global distribution (see Figure 3). Figure 3: Global locations of temperate rainforest biome (Weigand et al, 1992, see Worrell 1996). There may also be small areas on the coasts of France, Spain and Portugal. 8

9 Woodland communities Atlantic woodlands include the following woodland communities: Oak-birch woodland W11 and W17. Ash woodland W9: usually in small patches. Alder and willow wet woodlands - mainly W4 (downy birch) and W7 (alder). Hazel woodland that do not fit well into the National Vegetation Classification (NVC). Pine woodlands W18. Woodland conservation effort in recent decades has focused strongly on oak woodlands because of their botanical importance for bryophytes and lichens, their greater extent and their dominance in designated sites. Ash and hazel woods have received less attention in the past, though many ecologists would now rate them as at least as important as oak woods, not least because they have a more natural composition and structure compared to many coppice oak woodlands. Ancient hazel woods with long site occupancy have recently received considerable attention (Coppins et al. 2008). Alder and willow woods can have important bryophyte and lichen elements. The extensive areas of recent W4 downy birch woodland are of more limited value at present, although they may provide valuable habitats in future. Some NVC pinewood sub-communities (notably W18d Sphagnum capillifolium/ quinquifarium and W18e Scapania gracilis) share aspects of the lower plant interest with Atlantic broadleaved woodlands and have similar management needs. Guidance will focus on the following plant communities: W11b Blechnum spicant sub-community, W17a Isothecium myosuroides Diplophyllum albicans subcommunity, and W9 ash woodlands and hazel scrub. Wet woodland and pine communities, which often occur in intimate mosaics with the main oak-birch and ash woodlands, are included as associated woodland types. 2.2 Current management of Atlantic woodland Current woodland management as it influences woodland flora is best described in relation to two main factors: Management of tree cover: this covers interventions to alter the composition and structure of the canopy which can influence woodland flora and spans a range from no management (neglect) through minimum intervention to conservation management and multi-purpose management. Management of grazing: this covers grazing by both wild deer and domestic stock; and spans the range from no control (high grazing pressure), to controlled grazing (by fence and/or deer culling or via woodland grazing plans), to zero grazing in fenced plots. These two factors are encountered in a surprising number of permutations to give the main management scenarios: 1. No woodland management: no woodland management or restricted to opportunistic removal of small quantities of firewood. a) Unenclosed grazed woodland: woodland (and wood pasture) used as grazing and shelter for farm stock and/or deer. Where densities of farm stock are high (especially sheep) this is usually unfavourable for most plant communities, though it can be acceptable in the short term for epiphytes. At lower grazing densities and/or seasonal grazing, it can be favourable for some bryophytes and many lichens. 9

10 b) Woodland enclosed by stock fences but with no deer control: woodland (and wood pasture) often regarded primarily as deer shelter. Woodland is often moderately favourable for ground flora and favourable in areas which are difficult for deer to access (ravines etc); often favourable for epiphytes and bryophytes on boulders. c) Total exclusion of grazing: this happens temporarily over small areas when broadleaved woodland is deer-fenced for other purposes, usually fences erected for commercial forestry. This can give rise to young regenerating broadleaved woodland, which can be temporarily detrimental to lower plant communities. Absence of browsing can be favourable for woodland plants for a year or two, but rapidly becomes unfavourable. However, deer populations usually penetrate these areas after a few years and they revert to type 1b above, although shading in highly stocked young stands can be detrimental to lichens. 2. Conservation management: this occurs as a) minimum intervention restricted to deer control and removal of exotic species and b) active conservation management which involves improving the composition and structure of the woodland in addition to deer control and removal of exotics. Work directed at diversifying the canopy, encouraging native shrubs and increasing deadwood is generally beneficial for all plant groups provided it is done sensitively and no trees with rare epiphytes are removed in thinnings. Both management approaches are encountered on woodland nature reserves and increasingly in private and Forestry Commission woodlands. a) Without deer control: scattered tree and shrub regeneration might be protected by guards. Generally moderately favourable for woodland flora and favourable in areas which are difficult for deer to access (ravines etc). b) With deer culling under deer management plan: with deer control at a level intended to allow recruitment of tree regeneration in gaps and at woodland edges. Generally favourable for woodland flora as browsing is never wholly eliminated, but can be detrimental to those bryophytes requiring heavier grazing / browsing, or where canopy gaps critical for lichens become infilled by tree shrub regeneration. c) With controlled grazing: controlled grazing under a woodland grazing plan intended to improve woodland flora. Potentially a highly favourable management regime, currently only implemented over small areas in woods traditionally grazed by cattle (under FC stewardship grants). d) Deer control primarily by fencing: typical of regeneration areas in native woodlands. Allows recovery of regenerating trees and shrubs. Total exclusion of grazing instituted to encourage regeneration of trees and shrubs eventually becomes damaging for many ground flora species, although tall herb communities can prosper on some sites. 3. Multipurpose woodland management: this usually involves management aimed at small scale timber extraction by thinning and group felling, with or without deer control, and often includes elements of conservation management. On an appropriate site, at a sensible scale and done with care, timber management is typically neutral or only slightly/temporarily damaging for some woodland plants and over the long term can be compatible with conservation of plants. If carried out on important plant sites and done without regard to the flora of the site, this can be damaging, especially for lower plants. Recent history of management Prior to about 1990, the management of the majority of woodlands could have been 10

11 characterised as neglect i.e. they were unmanaged woodland on estates and farms 3, simply used as pasture and shelter for deer and farm stock, with occasional local cutting for firewood. There was a scatter of well-known instances of minimum intervention management, mainly on oak woodland national nature reserves (e.g. Ariundle in Sunart, Glen Nant near Taynuilt and Taynish, near Crinan). Parts of these areas were subject to small group fellings to attempt to initiate a new age class of trees, though this rarely had the intended effect. Oakwood SSSIs increasingly had SSSI plans, which were either implemented or not, according to the wishes of owners. A few woods were managed sporadically for timber, although this mainly took the form of opportunistic felling of more valuable trees. Starting in the early1990 s, renewed interest in native woodland had the effect of encouraging management of oak woods, often promoted by native woodland initiatives with support from Forestry Commission and Scottish Natural Heritage (e.g. This encompassed a range of approaches from minimum intervention, to active conservation management aimed at restructuring and promoting regeneration, through to multiple benefit management with an emphasis on small scale timber harvesting. Fencing aimed at total exclusion of grazing and browsing was common practice. At the same time there was an increasing appreciation of the botanical and cultural value of grazed wood pastures and veteran trees, especially in western Scotland. Starting in 2003, these approaches were augmented by initiatives to encourage controlled woodland grazing of livestock initiated by farm woodland interests (Sumsion and Pollock 2006). The main manifestations of these factors have been: A significant increase in the area of woodland enclosed by either stock or deer fencing and increased culling of deer within large fenced enclosures (Ratcliffe and Staines 2005). Some attempts to diversify oak monocultures by group felling aimed at initiating oak regeneration. Dense birch regeneration with rowan and some oak regrowth has been the usual outcome. Attempts to harvest small quantities of oak timber to supply mobile sawmills. A series of trials of controlled grazing by domestic stock supported by S9 Stewardship grants under the former Scottish Forestry Grant Scheme. Ongoing restoration in some significant areas of PAWS plus a few small areas of Rhododendron clearance. Until recently, an increasing number of woods being the subject of management plans. Many of these have now expired with no grants schemes in place to continue them. Very recently, signs of an increase in firewood extraction and the installation of mini hydro schemes. Both have the potential to impact negatively on lower plant communities in high botanical value woodland. 2.3 Management for woodland flora Efforts to introduce management aimed specifically at woodland flora have begun. These have generally been limited to: Botanical and site condition monitoring surveys of important sites, that have mainly fed into management plans for designated areas. Awareness raising, involving a limited number of owners and agencies, but latterly more widely via targeted publications and events. 3 The vast majority of Atlantic oakwoods are on privately owned land. 11

12 Control of grazing: the traditional reliance on permanent fencing is being replaced by limited efforts to institute temporary fencing, deer culling under deer management plans and controlled grazing using the Woodland Grazing Toolkit. Removal of exotics especially Rhododendron ponticum, with site-based projects being replaced by a more strategic approach. Management guidance for plants Management guidance specifically aimed at safeguarding and enhancing plants in Atlantic woodland has been developed in the last five years (e.g. Coppins and Coppins 2005, Rothero Thompson et al. 2005). The Atlantic Oakwood Symposium in 2004 led to the production of papers providing management principles for bryophytes and lichens, with particular reference to Atlantic oak (summarised in table 1). This has been followed by the publication of a new series of identification guides by Plantlife Scotland describing the key common lichens (Acton and Griffiths 2008) and bryophytes (Rothero 2010) of Atlantic woodlands and providing a means for non-experts to engage with the identification of important species. Management guidelines for fungi in Atlantic woodland are limited to general guidance on deadwood (Watling 2005) and on hazel gloves fungus (Coppins et al 2007). Recent woodland management guidance seeks to integrate conservation management with wider economic and social objectives, giving prescriptions which are widely applicable and fairly pragmatic (Peterken and Worrell 2005, Thompson 2005, Quelch 2005). Peterken and Worrell developed 5 management models (long rotation high forest, standard rotation high forest, minimum intervention, wood pasture, coppice) to help steer woodland management in the Sunart Oakwoods. These give owners a range of options and if all models are represented within a catchment, would safeguard conservation interests whilst allowing some productive use. In addition, progress has been made in landscape scale management using the Forest Habitat Network approach (Moseley et al. 2005), the output of which is generally sound for woodland flora provided low dispersal distances are used. Responding to the need to thin oakwoods, Thompson et al. (2005) produced innovative guidance on how to select trees for thinning using a process that includes assessment of the value of epiphytic bryophytes and lichens on individual trees and boulders. Collectively, current guidance adopts the following general positions: That current bryophyte and lichen interest of oakwoods is high and needs to be protected from unwise management intervention and invading exotics (Coppins and Coppins 2005, Rothero 2005, Long and Williams 2008). Management to increase the structural and tree species diversity of woods, if done carefully, can be compatible with conservation of bryophytes and lichens (Peterken and Worrell 2005, Thompson 2005, Quelch 2005). Careful management of the woodland canopy can increase bryophyte and lichen diversity especially in the longer term e.g. by producing a new generation of veteran trees, enhancing species diversity and increasing deadwood (Thompson 2005, Coppins and Coppins 2005). Conditions for woodland plants can be improved by controlling grazing (Sumsion and Pollock 2006). Coppicing of ancient hazelwoods can be highly detrimental for epiphytes (SNH 2008). Conditions for some species groups, especially lichens can be improved by diversifying the structure and composition of woods. Translocations of missing plant species may be beneficial for common woodland species in some limited circumstances (Coulthard and Scott 2001). 12

13 Table 1: an overview of the main habitat requirements, threats and management recommendations for different plant groups (based on Rothero 2005 and Coppins and Coppins 2005) Habitat requirements Main threats Favourable, or at least neutral, management practices Woodland herbs, small shrubs and ferns Variety of light levels accord-ing to species Intermediate grazing levels Appropriate tree and shrub species in the canopy according to site Invasion by Rhododendron ponticum & beech Over grazing Zero grazing Perpetuation of oak canopy on ash woodland sites Controlled grazing Removal of Rhododendron ponticum and beech Minimum intervention management Thinning and small group fellings in uniform woodland canopy Bryophytes and epiphytic ferns Suitable substrates: rocks & trees Constant high humidity Old veteran trees Deadwood Clearfelling Felling of high biodiversity trees, Felling/thinning on southerly aspects Felling thinning near key gorge sites Timber extraction that reduces deadwood Invasion by Rhododendron ponticum & beech Excessive shading by exotic trees/ shrubs Over grazing Zero grazing Disruption of boulders & rockoutcrops by creation of extraction routes and forest roads Controlled grazing Removal of Rhododendron ponticum & beech Minimum intervention management. Buffer strips along watercourses and ravines and near high biodiversity sites Careful thinning based on bryophyte biodiversity of individual trees Removal of infilled saplings around old open grown tree Favouring large trees during thinning which can become future veterans Avoiding chemical control of bracken on high biodiversity sites 13

14 Lichens Suitable substrates High humidity Variety of light levels mainly semishade Variety of tree and shrub species Old, veteran trees Presence of deadwood Intermediate grazing levels Clearfelling Felling of high biodiversity trees veteran trees Felling which reduces deadwood Coppicing of hazelwoods Invasion by Rhododendron & beech Over grazing Zero grazing Controlled grazing Removal of Rhododendron ponticum & beech Maintain full range of tree sizes Variable stocking and irregular thinning. Small group fellings in uniform woodland canopy Removal of infilled saplings around old open grown trees No gap infilling with planted trees Prevention of development of dense understorey 14

15 3. Guiding principles for woodland management Woodland dynamics and long term management: woodlands inevitably change and develop slowly through time in long cycles, with only some stages (mainly with mature / over-mature trees) being optimal for many specialist plant species. However, all the phases of woodland succession are inevitable over a long time period and the different plant species have their own strategies for dealing with them. Therefore, the wide variety of woodland structures and compositions which comprise the natural successional stages are potentially acceptable expressions of favourable habitat conditions. Sometimes short term losses of plant diversity may occur, followed by gains in the longer term; for example, this could happen when a wood is thinned in order to promote a new generation of older, large trees. The benefits or impacts of different management options can only be assessed using timeframes measured in decades or longer. Landscape scale: the ecological quality of woodland for plants needs to be assessed on whole woodland or catchment scale (10-100ha or more), as well as at stand scale. An oakbirch woodland which is 99% birch may look non-optimal, but if the rest of the woods in the catchment turn out to be oak monocultures, it suddenly becomes desirable as an element of diversity. Similarly management options can only be judged at these larger scales. It is usually desirable to manage to achieve a variety of age classes and woodland structures at catchment scale but makes no sense to attempt to represent these in individual woods (as has misguidedly been attempted in places during recent decades). The overall pattern to strive towards is a dynamic patchwork of different woodland conditions with the various stages slowly shifting their locations through time. Analyses at landscape scales via the IPA or Forest Habitat Network (FHN) models can be used to make informed decisions as to how best to optimise the development of high quality habitat patches into larger networks. The formation of networks aids dispersal of species and creates larger more resilient populations. This approach can work at all scales from habitat patches within individual woodlands, to woodlands within a catchment. This approach is thought to work well for plants even though many woodland plant populations appear to be able to survive in small habitat patches and have relatively poor dispersal capabilities. Natural v. artificial: it has widely been assumed that natural compositions and structures, together with the processes that gave rise to them, are always desirable. Whilst this is still a safe assumption in many cases (especially in closed canopy woodland), some artificial conditions arising from past management are also valuable and worth perpetuating. Indeed the distinction between natural and artificial is often sufficiently hard to define in theory and observe in the field, and can become a distraction rather than a useful tool. This can be illustrated by wood pastures; they are clearly highly valuable ecologically, but have many artificial aspects 4. They may have had natural counterparts in the distant past but their status in historic and prehistoric times can currently only be guessed at. The filling in of old wood pasture by natural regeneration to form closed canopy woodland is a natural process leading to what most people would regard as a more natural structure, yet it is usually ecologically undesirable. Artificial aspects of woodlands need to be assessed for their own ecological value and only changed if there are clear biodiversity (or other) benefits, rather 4 The setting of the boundaries of woodland SSSIs and SACs illustrates the potential pitfalls. Designated areas usually include only the closed canopy woodland, most of which had been intensively managed for timber in the past and excluded many far more valuable areas of habitat in adjacent old wood pastures. 15

16 than being changed simply because they do not conform to our current view of what might be natural. Disturbance: disturbance is a natural process leading to cyclical changes in woods and with different plants losing and gaining as a result of disturbance episodes. The assumption should not automatically be made that disturbance is bad and will damage plants; this will be true of some species, but others actually require periodic disturbance. It is useful to try to form a picture of the disturbance regimes in different parts of woods and how different plants cope with them. Management interventions aimed at introducing greater diversity into woodland (and/or harvesting timber) often share some attributes with natural disturbance. Knowledge about how plants cope with natural disturbance allows you to assess the effects of these management operations. Disturbance regimes in Atlantic woodland tend to be dominated by small scale events causing death of individual trees and small groups due to wind (distribution of events influenced by poor rooting in waterlogged or shallow soils and by occurrence of disease), overturning of trees in ravines and other steep side slopes (due to leaning growth habit and poor rooting), disease especially in birch and ash, flood and landslip beside watercourses and occasionally drought. Large scale wind disturbance events occur, but the greater frequency of damaging winds in Atlantic woodlands may be offset by trees being to some extent adapted by constant exposure to high winds. Furthermore oak is relatively resistant to wind damage, although birch is not. The role of phoenix regeneration in creating habitat for epiphytes has been noted in the field (Coppins pers. comm.) and may have been under estimated to date: this occurs where significant wind-blow events cause mature oak trees to be blown over, which then put up regenerative growth. Fire sufficient to cause tree death is very rare, although out of control muirburn is very damaging. Refuges with long periods between disturbance events exist in old woodland in very sheltered sites with good soils (such as some types of ravine), whereas disturbance cycles elsewhere are probably shorter. All this suggests that woodland ground flora is very well adapted to small scale disturbance events at time scales ranging between short (e.g. in birch or wooded ravine sides) to quite long (many oakwoods). Trade-offs: different plant species have different habitat requirements and so respond differently to management interventions. For example, conditions for lichens may improve following careful opening of the canopy whereas this may not be the case for bryophytes. There will always be difficult trade-off to make, at all scales from choosing individual trees in a thinning operation (see Thompson 2005), through to choosing management options for individual woods at catchment scale. Personal attitudes to timeframes and intervention: some managers prefer to rely on natural mechanisms to effect change, which typically act slowly and have relatively uncertain, although naturalistic outcomes. Others prefer to do use more interventionist management techniques, which produce faster and usually (but not always) more certain outcomes. There is frequently no way of resolving which approach is best; it is a matter of personal preference and the unique combinations of factors at each site. Professional attitudes ebb and flow somewhat, and recent decades have seen a preference for less interventionist approaches in general (e.g. fencing is now seen as problematic), but a greater acceptance of well thought out management intervention where benefits are proven (e.g. the thinning of Atlantic oakwoods reported by Thompson et al 2005 and controlled grazing). Few right answers: there are two management options that are universally viewed as positive: these are the removal of rhododendron and the institution of appropriate grazing. 16

17 However beyond these, there are few wholly right answers in determining the management of individual woods. Managers need to be able to make a clear case for their chosen management interventions (or the lack of them) and to be able to justify them in the face of apparently equally viable alternatives. 4. Landscape scale planning for woodlands This involves analysing the distribution and conservation value of woodlands in order to determine how they contribute to habitat networks and how networks can be improved. This allows the most important areas of woodland for conservation work to be identified. This is useful mainly for organisations involved in the setting of priorities at regional scale. Landscape scale planning for woodlands can be done as an Important Plant Area exercise (see section 1.3), or, to give greater detail, as a forest habitat network project (Moseley et al. 2005, 2007). In both cases the aims will be to classify the current woodland habitat according to its conservation value and then determine, in this case: 1. Areas/networks of native woodland of high conservation value which can act as core habitat from which species might be able colonise adjacent lower quality woodland. 2. Areas of lower native value woodland which can contribute to networks by being restored to higher value woodland. 3. Plantation conifers, some of which might be best converted to native woodland. 4. Which areas of woodland can most usefully be expanded in order to improve networks. This involves developing fewer larger networks in a catchment to replace smaller scattered ones. It also requires determining the conservation value of the open land that new woodland might be established on (so as to avoid impacting on valuable open ground habitats). The order of priority for conservation work that emerges from IPA and FHN analyses will generally be as follows: Priority 1: Protect and improve habitat condition of native woodland in core areas (FHN= Core Habitat). Focus first on areas of highest quality woodland. Priority 2: Improve habitat condition of woodland in zone of opportunity (= FHN restoration and conversion zones) starting with areas adjacent to areas of core habitat. This will involve work to improve the conservation status of native woodland (= FHN restoration zone) or convert plantation conifers to native woodland (= FHN conservation zone). Priority 3: Expand native woodland in core area into adjacent non-wooded area in the zone of opportunity (= FHN expansion zones) if appropriate and feasible. This is best done in a way that expands the highest quality woodland and/or creates the largest networks and has least impact on any valuable open ground habitats. The West Coast IPA analysis will be available at when complete. Details of how to carry out FHN analyses are given in Moseley et al and FHN maps generated using low dispersal distances 5 (of perhaps m) are most appropriate, as 5 Forest Habitat Network maps use specific dispersal distances (from a few hundred metres to several km) to illustrate how woodland blocks are effectively connected into networks for 17

18 woodland plants are assumed to have low dispersal capabilities (Long and Williams 2008). The management techniques most appropriate for implementing these priorities are described in section 5.2. Using GIS mapping to assess conservation value at landscape scale GIS mapping of woodland can make a good start on identifying areas of high quality woodland by focusing on designated areas and ancient semi-natural woodland. However, the databases used have some problems associated with them. As a result, maps can be broad brush and contain substantial local inaccuracies, notably missing many smaller woods of high conservation value (e.g. ravine woodlands) and highlighting areas of ancient semi-natural woodland of only moderate value due to past history of intensive coppice management. Initial maps built from publicly available data should ideally be supplemented and tested against more detailed records and reports from species experts. These include reports commissioned by SNH, National Trust for Scotland and Scottish Wildlife Trust for example and rare and threatened species databases held by the specialist societies and often available at All lichen surveys commissioned by SNH and others in Scotland are listed at E&hl=en_GB. Plantlife is completing this process through IPA mapping, which will be available once complete at Such maps are, however, only suitable for strategic planning and not for making management decisions for individual sites. Using GIS to assess the conservation value of open ground adjacent to woodlands, that might be suitable for woodland expansion, is also extremely difficult. It is possible to get some indication from GIS layers describing broad vegetation types (especially for mires/peatlands) and landuse categories. However, ultimately, it is always necessary to carry out a ground survey. Using Peterken / Worrell management models for oakwoods One of the aims of the Peterken/Worrell management (stewardship) models was to try to ensure that full the range of different woodland management models were represented in individual catchments / regions. This involves assigning woodland blocks (i.e. groups of individual woods) or individual woodlands to Peterken/Worrell management (stewardship) models (Peterken and Worrell 2005; Quelch 2005). Information on broad management prescriptions for the different models are available that can be used to develop woodland plans (Quelch 2005). The five models (according to Quelch s titles) are: Natural Reserves (minimum intervention 6 ) Ancient Oak Forest (long-rotation high forest) Native Timber Stands (standard rotation high forest) Coppice Wood pasture This is particularly useful for ownerships interested in management that includes an element of timber production, as the models attempt to balance conservation with productive use. species with different dispersal capabilities. 6 Peterken Worrell titles in brackets 18

19 5. Site (woodland) scale management This section sets out the how managers and owners can: Assess the (botanical) conservation value of individual woods or parts of woods. Identify problems affecting plant communities. Draw up prescriptions to address the problems that can be entered into a woodland plan, woodland grazing plan or SSSI or LBAP plan. At this stage it is assumed that it is useful to know how to improve the conservation value of all areas of woodland, irrespective of their current conservation value and scope for improvement. Once the conservation status (botanical value, woodland condition, management needs) of a woodland or group of woodlands has been assessed, it becomes possible to prioritise those areas most deserving of attention. 5.1 Assessing woodland and drawing up management prescriptions The process of determining the best management prescriptions starts by assessing the botanical value of the site, then moves on to consider the woodland condition and ends by determining the management needs. The stages involved in this are summarised in figures 4 and 5 below. Step 1 Assess the value of the flora (botanical value) The aim is to distinguish areas with high botanical value from more ordinary areas of Atlantic woodland. Areas with high botanical value are distinguished by: Areas with diverse and complete plant communities, including the presence of characteristic or rare species or communities, especially lichens and bryophytes. Presence of ancient woodland with ancient woodland indicator species. Favourable topography (ravines, watercourses) and microtopography (rocks, boulders, crags). Favourable gazing levels. Low levels (usually but not always) of past management. The first step in surveying woodland is often to do an initial rough survey which might be no more than a fairly rapid walk around the wood. This allows you to do a quick assessment of the flora and woodland condition and to roughly divide the wood into provisional management units according to topography, woodland type, condition and immediately apparent management needs. These management units should have broadly similar woodland characteristics and management needs. Their boundaries can be adjusted as survey of the wood progresses. Following the simple guidance given here helps woodland managers to assess the botanical interests of the site, without detailed knowledge of bryophytes and lichens. Hopefully, this process will also enhance appreciation and enjoyment of the wide botanical diversity of Atlantic woodland sites. 19

20 Figure 4: outline of process for determining management prescriptions for woodland flora. 1. ASSESS WOODLAND FLORA (BOTANICAL VALUE) Draw up plant lists and determine National Vegetation Classification woodland type. Identify areas of the wood of high botanical value focusing on lichens and bryophytes. 2. IDENTIFY ANY PRIORITY SPECIES OR COMMUNITIES Determine whether there are plant species / communities that should be afforded particular priority. These will usually be bryophytes and/or lichens. 3. ASSESS CONDITION OF THE WOOD Describe / assess the features of the woodland that have a bearing on plant communities both positive and negative (grazing, woodland composition, woodland structure, regeneration etc). 4. WHAT ARE THE KEY PROBLEMS AND CONSERVATION MANAGEMENT PRESCRIPTIONS? Determine conservation problems and management prescriptions that address these. OTHER MANAGEMENT PRESCRIPTIONS Consider the effects of management prescriptions for other objectives (productive use, recreation, grazing) on vegetation. Amend as necessary. 5. IMPACTS OF PROPOSED CONSERVATION MANAGEMENT Consider any impacts of proposed management prescriptions on other aspects of conservation value and wider management objectives (productive use, recreation, grazing). Amend if necessary. Tradeoffs will be necessary. 6. WOODLAND PLAN Enter prescriptions into a woodland plan, woodland grazing plan or SSSI plan. 20

21 The next step is to carry out a full survey, during which plant species lists are drawn up. The aim of this is to divide the site into areas with similar vegetation according to: 1. Woodland NVC community: to help provide an overview of (mainly) vascular plants and to guide general woodland conservation management; 2. Botanical value: to identify areas with high quality plant communities, focussing mainly on lichens and bryophytes. Most woodland or ecological surveyors will be able to draw up a satisfactory list of vascular plants and assign sites to a woodland NVC type. However some surveyors will have difficulty with lichens and bryophytes; and unfortunately there are currently only a small (but increasing) number of surveyors with a good knowledge of these lower plants who might be called upon to help. To overcome this, a method of assessing the botanical value of sites is provided below which requires little or no prior ability to identify lichens and bryophytes. The approach uses 2 levels of assessment: Plantlife Level 1 Assessment of Botanical Value: this requires no identification of lichen and bryophyte species, but presence of habitats suitable for important lichens and bryophytes are inferred from canopy and topographic features. This is thought to be sufficient to flag up areas of potential higher botanical value. These would ideally then be assessed using the Level 2 (below) to verify the existence of the most obvious lichens and bryophytes. Plantlife Level 2 Assessment of Botanical Value: this requires identification of a small number of lichens and bryophytes using Plantlife identification leaflets (Acton and Griffith 2008; Rothero 2010). Most woodland /ecological surveyors willing to invest a little time in identifying characteristic lichens and bryophytes will be able to use this method. In addition a list of characteristic plant species (vascular, bryophyte, lichens) is shown in Appendix 1 that can be used to add detail to areas identified as high botanical value. Presence of the species in these lists is further confirmation of the status of sites as high botanical value sites. Expert surveys Some owners and agents will be in a position to engage expert plant surveyors who will be able identify plants in all species groups and give a detailed picture of the value of sites. Guidance on assessments at this expert level is available (e.g. Coppins and Coppins 2002). Contact Plantlife Scotland or the Lower Plant and Fungi Advisor at Scottish Natural Heritage for a list of reputable expert consultants, who are able to conduct surveys to the highest standard. 21

22 Figure 5: evaluation of botanical value INITIAL SURVEY: Familiarise yourself with the wood and its vegetation. Divide it into provisional management units according to topography, woodland type and management needs etc. VEGETATION SURVEY: Make species lists for vascular plants and as many lichens or bryophytes as you easily can. Divide the site into areas with similar vegetation. Assign an NVC type to each provisional management unit. BOTANICAL VALUE ASSESSMENT LEVEL 1 REQUIRES NO IDENTIFICATION OF LOWER PLANTS Use the Plantlife Level 1 Assessment to identify areas of woodland that are potentially of high botanical value, focusing on bryophytes and lichens. BOTANICAL VALUE ASSESSMENT LEVEL 2 REQUIRES IDENTIFICATION OF A FEW KEY LOWER PLANTS Use the Plantlife Level 2 Assessment to identify areas of woodland that are of high botanical, focusing on bryophytes and lichens. Produce vegetation map showing NVC and areas of high botanical value. 22

23 Plantlife Level 1 Assessment of Botanical Value: Woodland areas are scored for the attributes shown in Box 1 by ticking the box in each row that best describes the site. The site (or part of a site) is then ascribed to a category of botanical value by looking at the weighting of the 6 ticks (low, medium, high). This approach gives a very basic assessment of sites and is suitable for use by all woodland surveyors. Box 1 Description Attribute Canopy cover Tree species Old trees Presence of rocks and boulders Low canopy cover of small/young trees/shrubs Mainly downy birch and/or alder Small/young recently established trees No boulders or crags, even terrain High canopy cover of small/young or mid-age trees Older trees, but still with most trees having silvery, rather than fissured, bark Scattered, small boulders or crags on even slope Ravines No ravines Minor watercourses with gradually shelving sides Green / brown epiphyte cover on tree boles and rocks looking like these pictures BOTANICAL VALUE See Image 1 below See Image 2 below High canopy cover (70-90%) of older trees and shrubs Mainly oak Older/bigger trees, with frequent trees with fissured bark Frequent larger boulders and crags on uneven slope Deep gully, but no waterfall or crags See Image 3 below Low canopy cover of veteran trees / shrubs or old woodland /hazel scrub with frequent glades Mainly elm, ash, hazel Old / big trees with fissured bark Large blocky boulders and crags; hard to walk across Deep ravine with waterfalls and crags See Image 4 below LOW MEDIUM HIGH 23

24 Image 1: Image 2: 24

25 Image 3: Image 4 25

26 Plantlife Level 2 Assessment of Botanical Value: Woodland areas are scored for the attributes shown in Box 2 by ticking the box in each row that best describes the site. The site (or part of a site) is then ascribed to a category of botanical value by looking at the weighting of the ticks (low, medium, high). Surveyors who need help in identifying lichens and bryophytes should use leaflets available from Plantlife Scotland (Acton and Griffith 2008, Rothero 2010). This approach gives a simple but fairly effective assessment of sites and is suitable for use by all woodland/ecological surveyors. All the species mentioned here can be found in the Plantlife guides (Acton & Griffith 2008, Rothero 2010). Additional species that indicate habitat quality will be present, but for the purposes of this exercise, it is sufficient to use the lichens shown in the guides. Box 2 Description Bryophytes Plagiochila spinulosa group (Plantlife guide) Not present Low abundance and restricted to unusual features Scapania gracilis Not present Low abundance and restricted to unusual features Hymenophyllum wilsonii (an honorary bryophyte in this context) Lichens Lobarion and Sticta species in Plantlife guide on ash, hazel, willow, rowan and old oak Not present Not present Crustose lichens Not present - hazel often covered in common mosses Species in Plantlife guide on birch, alder, oak Dominated by common species e.g. Parmelia saxatilis, Platismatia glauca, Evernia prunastri Low abundance and restricted to unusual features Low abundance and restricted to few features Moderate abundance on younger smaller stems with only a few species Any of the following species in low abundance and restricted to few features: Menegazzia terebrata, Parmotrema crinitum, Hypotrachyna taylorensis 26 High abundance over wide range of features High abundance over wide range of features High abundance over wide range of features High abundance over wide range of features Frequent crustose lichens on hazel and other species (e.g. rowan and holly) with a variety of species Frequent presence of any of the following on trees and rocks: Menegazzia terebrata, Parmotrema crinitum, Hypotrachyna taylorensis

27 Vascular species Dryopteris aemula BOTANICAL VALUE Strongly dominated by wavy hair grass and tufted hair grass Herbs restricted to more common woodland species i.e. primrose, honeysuckle, stitchwort, wood sage, common cow-wheat Nil Occasional Abundant LOW MEDIUM HIGH Frequent dogs mercury or sanicle The output of this stage should be a vegetation map showing the NVC communities and indicating the botanical value of the sites (see Figure 6). Individual species and habitats of note can be shown on maps as labelled arrows. Figure 6: a hypothetical example of a site vegetation map, showing NVC communities and the botanical value of the site 27