Holne Woods Site of Special Scientific Interest (SSSI) and Special Area of Conservation (SAC) for 'Old Sessile Oakwoods with Ilex and Blechnum in the British Isles'.Ancient Semi-Natural Woodland (ASNW) classed as Upland Oakwood, formerly managed as coppice and wood-pasture, now with characteristic high forest structure.I swear that sometimes, no matter how much i try to explain the reasoning behind woodland management to members of the public, the perception persists that it is 'boys with toys' who know nothing, randomly creating mayhem with chainsaws and tractors. Its one reason i began this series of occasional articles on woodlands and their management, as a source of reference to refer the public to, utilising quotes from those whose lives have been devoted to the study of this most important of Britain's habitats. More than any other habitat, decisions made can impact, for good or bad, for decades after. There can be nothing random about it.
I believe that the management of woodlands requires an empathy and dedication that is not as keenly felt in other habitats. Trees are large organisms which people feel strongly about. You need to know what you want to achieve before a tree that is nearly 100 years old is removed in 5 minutes. In forestry the tree is merely a product, a crop. That is why i see a huge difference between forestry, the farming of trees, and the management of woodlands, as a whole ecosystem. This empathy towards woodlands and the constant quest for understanding them, my long suffering partner would call an obsession, as once again, in
our spare time i drag her around some wood or another ( though i am quite proud of her knowledge compared to the average member of the public..maybe she does listen sometimes). Often it is Hembury and Holne Woods we go to at weekends, of which i am proud to be a warden for. But how can you
not be a guardian for such places and not want to have an intimate knowledge of every stand and area of coppice, where the rare trees are, and where the woodland archaeology can be found? How, more importantly, can you be responsible for the management of such woods without a detailed knowledge that has led you to decide where, and how, work is to be implemented?
To answer this we need to know the answer to several questions (there is more to it but we need to simplify this).
What is the history of the wood? What is the woodland type? What is the woodlands structure? What wildlife does the wood support? What are the timber and wood objectives? What are the long term objectives?References are made throughout to previous
'Woodlands' blogs and are highlighted in
bold green.
It is also worth noting that this blog is rather long and involved, so if you are not
that interested in woodlands, i would skip this one. You have been warned...and i promise i am unlikely to do another this long! Like i have said, this is building up the reference for future, shorter, blogs.
History of the wood Woodland is the naturally dominant vegetation formation of most of Britain, and woodland of ancient origin, that is, woodland that retains this link to the wildwood, is thus the priority for woodland conservation. Secondary woods and plantations have value but rarely posses the suite of species to be found in ancient semi-natural woodland (ASNW).
Note; for an explanation of these terms see 'Seeing the wood for the trees'.The emphasis from here on in is therefore upon ASNW, which is our most valuable form of woodland nationally, and which covers the majority of National Trust woods on Dartmoor.
Woodland nature conservation as regards ASNW puts a stress on habitat continuity and the species that have been sustained through this.
Thus, as George Peterken says in
Natural Woodland(1996);
'This emphasis on origins and stability has led to history becoming more of a basis for nature conservation in woodland than in other habitats. Historical studies have focused on identifying the remnants of the original woodland and elucidating the effects of millenia of use and management. In other habitats, the historical element is a less important factor....'
As briefly outlined in
'Reading the wood', the wood itself gives us these clues as to use and management so long as we know how to look. Comprising of such long-lived plants, the trees themselves inform us as to how they were previously managed. Again, as mentioned in this same blog it would have been in one of four ways; coppice, coppice with standards, high forest and wood pasture. Once you know the clues you can go to most woods and tell how it was historically managed so that the history of land use informs us in the present of the current wood, and the direction in which its future might head. Alongside this we have 'old forest lichens' and 'ancient woodland indicators', plants associated with ASNW. Such plants have responses to various forms of management which helps in deciding which form of management to take, and help illustrate how a wood was once managed.
ASNW due to its long associations with use and management by man also contains direct links to the past in the form of archaeological features such as hillfort's and barrows, medieval boundary banks, and charcoal hearths and saw-pits reflecting industrial use of woodlands.
Woodland type An oakwood in the south-west is completely different from an oakwood in the south-east. The lime woods of the east are unique to that area. The beechwoods of the south have a historical significance there that is not true elsewhere where it has been introduced through planting ( see
'A place for Beech'). Correspondingly, the floras and faunas are different. Thus, the maintenance of these different woodland types (as defined in both botanical and structural terms) throughout their current ranges is of the utmost importance.
Again, as mentioned in
'Reading the wood' , naturalists have devised systems for classifying woodland into types, from the National Vegetation Classification (NVC) of 25 woodland and scrub communities, to George Peterken's 12 'Stand Types'. The Forestry Commission have greatly simplified matters by recognising 8 broad ASNW types based on composition and geography (see notes at the end of the blog).
It should be remembered that though two woods may be of the same vegetation type, if one is regularly coppiced and the other is high forest (ie, they have a different structure), the bird and invertebrate life will be very different.
Such things as the NVC and Stand Types should not be seen as the only way of describing woodland, but rather as one element in such descriptions.
This variation of woodland types often has recognition at a European level as a Special Area of Conservation (SAC), and as a habitat type at regional level in Biodiversity Action Plans (BAP's) (again, see notes at the end of this blog).
The tree species present in our woodland type further informs us as to which forms of management would best suit them. Trees such as oak are intolerant of shade, so to maintain the succession quite large scale felling areas are needed in oakwoods. Beech on the other hand is able to grow in shade, so a beechwood can be sustained through selective and group felling.
Thus, where we are in the country dictates the woodland type, which informs the management system we initiate, which is informed by the history of the individual wood and the history of that woodland type within the region. The next factor in it's management is its current structure.
Woodland StructureThis is strongly linked to the botanical woodland type, but through man's historical use of woodlands (hence our need to understand woodland history) the past management system and the current stage of growth (the structure) influences what flora and fauna are, or should be, present in the woodland type to inform us in our management decisions.
As mentioned, all ASNW (regardless of woodland type) would have been managed in one of 4 ways ( or 3 if you combine coppice and coppice with standards - see the quote below) that each produce different, but easily recognisable structures, though this is somewhat masked either by forestry practices or by no management at all in the last 70 years.
As R.J.Fuller and M.S.Warren in
'Management for biodiversity in British woodlands-Striking a balance (British Wildlife vol7 no1 1995) put it;
'Different management systems produce contrasting vegetation structures with particular communities of associated animals. From a conservation perspective, therefore, different woodland management systems should be regarded as complementary. Each of the 3 main classes of woodland management - coppice, high forest and wood-pasture - can be implemented in different ways, leading to substantial variation in woodland structure.'
The populations of flora and fauna found within woodland are strongly influenced by these variables of management. As Warren and Fuller go on to note, the focus for woodland conservation has been upon the two ends of the growth spectrum, that is, very young open stages (coppice) and very old trees (wood-pasture), 'young-growth' and 'old-growth'. As they note;
'Both of these broad habitat types have become increasingly scarce and fragmented in British woodland and require positive measures to maintain their associated wildlife'.
As an example, most of the National Trust woods on Dartmoor are oakwoods which were formerly managed as coppice-with-standards, thus they occupied the 'young-growth' end of the spectrum. Unmanaged in the last 70 years or so except in terms of forestry, the 'young-growth' interests have been shaded out. The woods are mid-succession, exhibiting characteristics of 'old-growth', but much work is needed to balance this out with the needs of species utilising early-successional habitat, which are rapidly declining. Nationwide much the same could be said for most ASNW.
To maintain and diversify structure within woodland we need to utilise these 3 main classes of woodland management- coppice, high forest and wood-pasture- alongside the various forestry systems for the management of stands, dependant upon what species occur (eg, selection systems for beech, shelterwoods for oak), and other objectives such as timber and wood .
What wildlife does the wood support ? The conservation value of 'young-growth' and 'old-growth' is a blog of its own, though it was touched upon, especially as regards 'old-growth', in
'There's life in the dead wood'. To simplify this for the present, we need to know what wildlife species, and their specific habitat requirements, need to be prioritised. What is present is strongly influenced by the woodland structure and type (as mentioned). I apologize for the length of the following quotation, but it ably sums up this section far better than i could, so here's George Peterken from
Natural Woodland (1996);
'Priority has to be given to 'vulnerable species', if only because they need more protection than resilient species. These include not only rare species, but also species with a poor dispersal or colonising ability, widespread species which habitually occur in small populations, species which depend on a declining habitat, and those which are subject to declining habitat, and those which are subject to wide fluctuations in numbers. One important element of vulnerability is isolation. Put generally, it is the ancient woodland species which need most protection.
Two practical implications emerge. First, the combination of habitat isolation and the limited ability of many woodland species to disperse, implies that woodland conservation should aim to maintain species and populations in the sites they now occupy. We cannot rely on recolonisation to make good any local extinctions. Woodland species at the edge of their range may be particularly vulnerable to future climatic changes, natural or artificial. Second, only a very limited number of species can be individually considered in designing management for particular woods, because autecological knowledge is limited, and plans have to be fairly simple to be practicable. This limitation may, however, be more apparent than real, for management plans can be designed around a small but representative selection of 'feature species', which should create optimal conditions for the woodland fauna and flora as a whole.'
Such 'feature species' as mentioned are usually those protected by law, covered by Biodiversity Action Plan's (BAP's) on a regional basis, or on the Red Data Book List.
Species (for example Dormice and Pearl bordered fritillaries) are covered by Species Action Plan's (SAP's) within the Devon BAP and are further protected through other legislation. These species are therefore the' feature species' we prioritise management for, with more common species benefitting by default.
Timber and wood objectivesSome may feel this is not compatible with other objectives such as management for wildlife, but the opposite is true as long as it does not conflict with conservation objectives. Therefore, remembering the importance of 'young growth' and 'old growth', as long as a high proportion of mature trees are allowed to senesce naturally, and therefore exhibit 'old growth' characteristics, objectives for the harvesting of timber and wood are entirely compatible with species specialising in early-successional habitat, ie, 'young growth'.
If the damage caused by extraction is incompatible with conservation objectives then it has more value as deadwood (see
'There's life in the deadwood') and should be left where it lies. As much as anything it is poor economics and poor PR, its value as pulp or firewood negligible compared to potential damage to the site and to public perceptions (though i must add that public perceptions of damage can sometimes be off the mark).
As R.J.Fuller and G.F. Peterken put it in
Woodland and scrub in
Managing habitats for conservation (1995);
'In ancient woods, especially on nature reserves, commercial considerations should be subordinated to those of conservation, whereas timber production is a major objective in most recent woodland.'
Long term objectivesThe long term objectives are probably the most important part of woodland management planning. Imagine yourself stood in a wood. You now know its history, what woodland type it is, what structure it has, what wildlife it supports, and what your wood and timber objectives are. Now imagine it in 10 years, 20, 30, 40 or 50 years. This long term vision is informed by all the questions we have asked, and should keep asking.
Woodlands are complex ecosystems, its responses slow and gradual so that decades can pass before a woodland area changed through management exhibits the growth structure envisaged. This is why the future must always be envisaged in the present.
R.J.Fuller and G.F.Peterken in
Woodland and scrub in
Managing habitats for conservation (1995) list 5 general principles to observe when planning the management of ASNW. Remember that these are only guidelines as is everything that i have written.
General principles such as these can be tailored to suit the needs of an individual wood. Following rigid pescriptions can sometimes fail to take into account that every wood is unique, even if it is of the same 'type' as another. What makes each wood special can be forgotten in the determination to fit a wood into prescribed guidelines of what it is, or what it should be. Anyway, over to Fuller and Peterken:
'Five general considerations should be borne in mind when planning the management of ancient woods:
1. Woods often act as reserves for the whole landscape, especially in intensively arable regions. Many, for example, should be regarded as grassland reserves, as well as woodland reserves, because ancient rides sometimes carry relic semi-natural grassland. Management of open spaces within the woods may, therefore, be at least as important as management of the tree stands themselves. Many woods are still linked to a network or mosaic of habitats in their surroundings, effectively a 'landscape-scale reserve'.
2. Management should aim to sustain all species now present within the wood. Most woods, especially small woods in intensively arable districts, are now so isolated that species with limited mobility cannot readily recolonise after local extinction.
3. Managers should base silvicultural treatments on the native tree and shrub species already in the wood. Maintenance of each species at its present level of abundance is not necessary, provided all species are retained. Maintenance of their present distributions within a wood is desirable, but minor adjustments are usually acceptable, especially if these come about by natural regeneration.
4. The long-term aim should be balanced age-structure within each wood or cluster of small woods. ideal treatments should aim to (i) maintain a continuous supply of young growth through regular felling and (ii) protect and enhance mature features, such as large trees and deadwood.
5. In the great majority of ancient woods, management should either continue or revive the management which was traditional in the wood, or incorporate the main habitat features of traditional management within high forest systems. '
All i will add to this is that these long-term objectives are purely for nature conservation, but as mentioned, wood and timber objectives can be compatible with the delivery of them.
I deliberated with ending this blog by briefly utilising what we have gone through with the example of one of the National Trust woods on Dartmoor, but this has been a long blog and the space remaining would not do justice to our woods. Instead we shall keep building up this resource of reference for when we enter the National Trusts Dartmoor woods themselves.
From all the above i hope there might be a dawning realisation that we as wardens are more than 'boys with toys' and that a lengthy process has been gone through before we even go near a wood with our chainsaws. Legislation has not even been touched upon.
NOTES1. The National Vegetation Classification (NVC) for woodlands and scrub has 18 main woodland types and 7 scrubs and underscrubs, most of which are further divided to give a total of 73 sub-communities (denoted by letters).
2. Oak woods such as found in Dartmoor's river valleys would be NVC types
W10a, W10e, W11, W16b or W17, Stand Types (after Peterken)
6a and 6b (with
8a and 8b where beech has been introduced). Under the Forestry Commission's broader categorisation of ASNW it is
Upland Oakwoods, which is also a Biodiversity Action Plan (BAP) Priority Habitat. The Special Area of Conservation (SAC) designation many woodland types have is a Habitats Directive Annex 1 Type, in the case of Dartmoor's oakwoods,
'91AO - old sessile oakwoods with Ilex and Blechnum in the British Isles'. This is further broken down into 'site accounts ' so that pretty much all of the National Trust woods on Dartmoor come under the
'South Dartmoor Woods' site account.
3. Other NVC/Stand Types can occur within a broader 'Type' of woodland, for example, a large stand of alder occurs at Hembury Woods in a wet area by the river, such woodland is NVC type
W7, Stand Type (after Peterken)
7, with various permutations of sub-communities.
4. The National Trust is lucky to have the Biological Survey Team who provide a comprehensive biological survey of every site. Unfortunately, with so much land ownership their visits are few and far between (20 years and 19 years respectively for Hembury and Holne Woods) so to add to the warden's skill sets, identification skills are necessary to know what you have on site as regards fauna and flora.
5. All woods within the National Trust are covered by a Woodland Plan outlining the long term vision and the objectives for a 5 year period.
6. The effects of deer (especially on lowland woods) and sheep (in upland woods) may be inhibiting the ability of many woods to internally regenerate and must be factored into decisions about woodland management (hopefully the esteemed Mr Jones might write a blog on this).
7. Climate change could change everything.
Pearl-Bordered fritillary (Boloria euphrosyne) at Hembury Woods SSSI/SAC. 
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