by A Jones (FCS), Forestry Commission Scotland, Edinburgh
Summary
The Caledonian Pinewood is an endangered habitat, and special measures are being taken to record and safeguard it. All the pinewoods in Scotland which are genuinely native, that is descended from one generation to the next by natural means, have been mapped, measured and information about them recorded in an Inventory. This work started in 1989, and was made available in 1994. Since then all the maps have been digitised and incorporated into a Geographical Information System. Much of the previous information has also been updated, and restructured as a database which can be installed on a PC. The Inventory is an important baseline, but there are no current plans to update it, because there are a number of more recent initiatives which will produce information of a similar nature about the pinewoods and the other semi-natural woodlands of Scotland.
Introduction
Scots pine (Pinus sylvestris L.) is the most widespread, naturally occurring conifer in the world, stretching from western Scotland eastwards nearly as far as the Pacific Ocean, and from the Arctic Circle to the Mediterranean. It is adapted to a wide range of climates and soils. In Scotland it is usually found on freely draining podzolic soils with rainfall as low as 700 mm per annum, but it can also grow on peat soils and where rainfall exceeds 2500 mm per annum.
Pinewoods became dominant over a large part of Scotland after the Ice Age, being limited only by the combined effects of soils, climate and the browsing effects of the larger herbivores, and in time the increasing exploitation and destruction of them by man. There are many examples in Scotland where macrofossils of pine have been discovered in peat (Bennett, 1995) and in some locations there are several layers of stumps to be seen in the peat profile.
The significance and intrinsic value of these pinewoods as part of our natural heritage was largely ignored, except as a source of timber, until the 1950s. This indifference was less evident following work on the morphological and silvicultural variation in native Scots pine and its implications for forestry practice in Scotland (Carlisle, 1954a, 1954b, 1956,1958; Steven, 1958,1961). It was, however, the book The Native Pinewoods of Scotland, written jointly by Steven and Carlisle (1959), that rekindled a more general interest in those pinewoods which were ‘genuinely native, that is, descended from one generation to the next by natural means’. In it, 35 pinewoods were identified and named, and subdivided geographically into 8 groups (see Table 1); maps were published for 27 of them. These maps were very small scale, and were based on annotated field maps at a scale of 1:10,560 (now stored in the Forestry Department at the University of Aberdeen). The original papers include some information about other pine areas which were not mentioned in the book, as ‘…these pine are so few in number they do not constitute definite communities and are not described….’.
The apparent decline of the pinewoods continued despite the stimulus of a symposium at Aviemore in 1975 (Bunce and Jeffers, 1977), and the introduction by the Forestry Commission (FC) of Native Pinewood Grants (Forestry Commission, 1978) as an incentive for their regeneration and expansion. By 1987 it was estimated that the total area of genuinely native pinewood was about 12000 ha (Bain, 1987).
The Native Pinewood Grants were reviewed and incorporated into the FC’s Woodland Grant Scheme (WGS) in 1989 to encourage the establishment of new native pinewoods on appropriate sites within the former natural distribution of Scots pine dominated pine-birch forest (Forestry Commission, 1989a). Then, as part of a broader initiative to promote the conservation and expansion of existing native pinewoods, the FC also published guidelines for their management, amplified the pre-conditions of eligibility for a higher rate of grant, and embarked on a project to produce a Register of Native Pinewoods (Forestry Commission, 1989b). The development of the Register, subsequently re-named the Inventory, is described below.
The 1991 Native Pinewood Register
The 1991 Register (Forestry Commission, 1991), initiated in 1989, was a collaborative effort by several locally based FC staff, collecting information for the pinewoods in their area. It included all the pinewoods identified by Steven and Carlisle, and some additional areas which were thought to meet the definition of nativeness that Steven and Carlisle had adopted. The outcome was a series of brief written descriptions of each pinewood and a set of maps, mostly to a scale of 1:10,000, which were variously coloured or photo-reduced. The way in which the boundaries of the most fragmented pinewoods had been determined was inconsistent, and some of the more extensive pinewoods (whose boundaries overlapped the edges of a map sheet) had been rather arbitrarily subdivided; some of the separate parts were given different names, and the continuity with the original Steven and Carlisle pinewoods was broken. Although the information was theoretically available for public inspection it was not user-friendly.
The 1994 Caledonian Pinewood Inventory
Graham Tuley was appointed as the FC’s Highland Native Woodlands Adviser in 1991 and asked to update and standardise the presentation of the 1991 Register. It was later decided that the ‘Register’ should be referred to (and in due course published) as the ‘Caledonian Pinewood Inventory’ in order to avoid confusion with the Register of Native Scots Pine Seed Collection Areas which the FC has maintained since 1989.
To produce the Inventory the pinewoods recorded in the 1991 Register were re-examined together with over one hundred other pinewoods which, it had been suggested, might fit the eligibility criteria. The aim was to ensure that the Inventory would only contain those pinewoods which consisted of more than 30 individual trees, where the balance of probability indicated that they were genuinely native.
In turn each of these pinewoods would normally have:
- a minimum density of 4 pine trees per ha excluding trees less than 2 m in height, or at least 50 stems per ha where the sites had been extensively underplanted with nonnative species but were deemed capable of restoration to a more natural state;
- a minimum of 30 individual trees, unless the wood had historical, aesthetic or biological significance;
- vegetation which was characteristic of native pinewoods, although possibly of a depleted diversity;
- a semi-natural soil profile, while accepting sites with superficial cultivation, such as shallow ploughing or scarification, with some widely spaced drains.
All the maps were checked and re-drawn at a scale of 1:25,000, which allowed most of the largest pinewoods to be accommodated on one sheet. Composite maps (at the same scale) were also prepared for any pinewoods which straddled the edges of standard map sheets.
The maps showed:
- Core pinewood areas – in effect the areas at the ‘heart’ of each pinewood where individual trees were closer than 50 m apart, and comprising reasonably viable units for management purposes, based on the assumption that most of the seed shed by the trees might land (and hopefully germinate) within 30 m, or twice tree height, of the parent trees. Minor discretionary adjustments were made to the core area boundaries of some pinewoods to avoid loss of site integrity by needless fragmentation, for example where the patchy distribution of trees would have resulted in several core areas being situated fairly close to each other. Pinewoods were regarded as discreet if their core areas were separated by more than 1.5 km. Ownership boundaries were ignored.
- Regeneration Zones, which were notional areas, normally 100 m wide outside the boundary of the core areas. This distance was increased to include areas of existing natural regeneration occurring slightly further away, or if there were good prospects of regeneration due to the prevailing wind direction and the topography. It was reduced where natural regeneration was less likely, for example where it was presumed that the pinewoods had a poor regenerative capacity, or because of some natural barrier (e.g. a loch). The zone was not restricted to ownership boundaries unless it made sense to avoid minor incursions into other ownerships.
- Buffer Zones which were also notional areas, normally 500 m wide outside the regeneration zones. These sometimes overlapped, and it was often expedient to include smaller pinewood fragments and the occasional isolated tree in one large buffer zone, such as within a watershed, though large areas of open water were usually excluded. Potentially overlapping buffer zones were not merged if their respective core pinewood areas were biochemically dissimilar (Forrest, 1980), and a mutual boundary was then determined.
Adjacent planted areas of Scots pine (known to be of the correct biochemical origin) covering less than a third of the total area were included as part of the regeneration zone. Where such areas exceeded a third of the total area, they were regarded as part of the buffer zone. Planted areas located more than 600 m from the core area (i.e. beyond the buffer zone) were not shown on the maps.
- A ? symbol was used to indicate:
- pinewood areas previously identified by Steven and Carlisle where the current stocking was well below 4 trees per ha, and without a measurable core area, but where indicative regeneration and buffer zones could be drawn;
- scattered or isolated pine trees remote from a core area, and where the exact number was not ascertained, or where the group was too small to map separately though there was a good pinewood flora which was worth conserving by developing the tree cover;
- areas which had not been surveyed, such as steep sided gorges which could contain pine, or where historical evidence suggested that there had been pine in this locality in the past.
On completion, the 1994 Inventory listed 78 pinewoods with a total (core) area of 16,046 ha (Forestry Authority, 1994a). Some of the pinewoods which had appeared in the 1991 Register were excluded as a result of more recently obtained evidence of their ineligibility, which usually meant that they were, or had been derived from, old plantations, e.g. some pinewoods in Deeside (Callander and Mackenzie, 1991). This was not unexpected as other writers have also observed that several apparently ancient pinewoods have been through a planted phase (Guillebaud, 1933; and Steven and Carlisle, 1959).
The increase in area since 1987 (Bain, 1987) was partly explained by the fact that the Inventory had been a more detailed exercise, seeking to evaluate some of the more distant and fragmentary pinewoods that Steven and Carlisle had not even mentioned. Aerial photographs, coupled with improved ground-truthing and mapping techniques, had also helped to confirm boundaries, and therefore improve the area measurements. It was accepted that the total area could still be an underestimate because of the difficulty of identifying and assessing other potentially eligible sites, for example where widely scattered trees were engulfed within extensive plantations (especially of Scots pine) at a mid-rotation stage.
The information in the 1994 Inventory was presented in a standard format, and it was more comprehensive than the 1991 Register. Observations made during recent site visits were included, especially if they clarified discrepancies in previously published information. In some cases a note was also made of any relevant site-related references in the scientific literature.
The Inventory was supplemented by a series of indexes to assist the reader, but even without the maps it was a very bulky document which would have been expensive to publish and distribute in the normal way. Pinewood owners or their agents were supplied with copies of the information held about the pinewoods they owned or managed, and copies of the whole Inventory were issued to Scottish Natural Heritage (SNH), Macaulay Land Use Research Institute and the Department of Forestry at Aberdeen University. Further copies were made available for inspection by the public at several FC offices, with the option of having photocopies of any of the information and maps on request. Regular usage of the Inventory in this format was probably limited to FC staff, other professionals, and researchers or students who were minded to examine it.
To promote the Inventory, and to provide an introduction to it, a simple leaflet was published (Forestry Authority, 1994b). This leaflet listed all the pinewoods and their areas, with suitable cross references to Steven and Carlisle’s book.
The Caledonian Pinewood Inventory 1998
Work to refine the Inventory continued after 1994. The Loch Assynt pinewood was deleted when it was confirmed that it had been planted at one time (Quine, 1980), but other surveys had ‘discovered’ another eight eligible pinewoods. These included Ardessie on the south side of Little Loch Broom, Lochourn River (not listed separately by Steven and Carlisle), Glen Buck which is south of Fort Augustus, and five other pinewood fragments in Deeside and in Strathspey. The maps were also digitised and re-measured, resulting in a revised overall area of 17,882 ha, confirming what was said earlier about successive surveys ‘finding’ additional areas of native woodlands – obviously not an indefinite process, but a situation that may persist until all possible areas are surveyed in detail. A summary of the pinewood areas, and their regeneration and buffer zones by Biochemical Region is given in Table 2.
The advent of Information Technology was an opportunity to overcome the presentational and distributional difficulties mentioned above, hence the decision to restructure the Inventory as a Microsoft Access 2.0 database so that it can be installed on a PC, (Forestry Commission, 1999). In the database, the information about each pinewood is given under a number of standard headings (see Table 3). Locational maps are included, and the user can switch between maps and pinewood records ‘at the touch of a button’.
Grid Reference and OS Map Sheet no. in the Landranger 1:50000 series.
Biochemical Region based on site specific test data by Dr lan Forrest of the Forestry Commission Research Agency, or by careful interpretation of previously published information about the Biochemical Regions (Forestry Commission, 1989b).
Designations (Natural Heritage) such as SSSI, SAC, SPA, NNR to indicate conservation status as applicable to all or part of the pinewood; some pinewoods have several designations.
Ownership (by category) such as Personal and Family (including Trustees), Business, Voluntary organisations, Public Body, Forestry Commission; some pinewoods cross several ownership boundaries, in which case all ownership categories are given.
Area(s) in hectares of (core) pinewood, Regeneration and Buffer zones.
Registered Seed Source(s) where applicable – identifying, by name and number, the native Scots pine seed collection areas within each pinewood.
Pinewood References – listing relevant references to the pinewood in scientific / forestry literature; completeness of the cross-referencing is not assured.
Forestry Commission Conservancy in which the pinewood occurs.
Local Authority in which the pinewood occurs.
Comments • by Steven and Carlisle (1959) from the book ‘The Native Pinewoods of Scotland‘; by Bain (1987) from the report ‘Native Pinewoods of Scotland – a review 1957 – 1987‘; by Tuley – site based observations by Graham Tuley (Forestry Commission Highland Native Woodlands Adviser 1991 -1996) during fieldwork for the Inventory; about Mapping Details – observations on how the boundaries of individual pinewoods were determined, especially in the most fragmented pinewoods; about the Biochemical Region – to justify what is stated above.
It was decided to add two other sections to the database. One, called the Inventory Analysis, is a simple spread-sheetstyle screen enabling the user to summarise some of the Inventory information based on key data, e.g. to list all the pinewoods within a specific Local Authority area, or of a certain biochemical type which are also wholly or partly designated as SSSI’s. Individual and total areas are given automatically. The other section, the Inventory References, is a list of over 800 literature references compiled originally by Graham Tuley. About half of them refer specifically to one or more of the pinewoods in the Inventory, and where relevant can be accessed directly from the pinewood records; others are a potentially useful source of information on pinewoods in general, including other pine species, and may enhance our understanding of Scottish native pinewoods.
Discussion
Interest in all of Scotland’s native pinewoods has increased enormously since the Pinewood Register/ Inventory project was initiated. There have been several ‘milestone events’. One was the adoption by the UK of the EC Habitats Directive (EEC, 1992): this has led to proposals to designate several pinewoods as Special Areas of Conservation. Another was a conference in Inverness in 1994 to review the latest scientific information about pinewoods (Aldhous, 1995). Pinewoods are also the subject of a Costed Habitat Action Plan (BSG, 1995) which uses the 1994 version of the Inventory as the base-line for its quantitative targets.
There are no current plans to update the Inventory which should be regarded as a historical statement based mainly on the Steven and Carlisle criteria. Other native woodlands survey initiatives are already in progress, notably the one led by the Caledonian Partnership. This was initiated as a project co-funded by the European Commission’s LIFE-Nature Programme (Caledonian Partnership, 1997), and then extended with support from the Millennium Forest for Scotland Trust to create the ‘Millennium Guide to Scotland’s Forest Resource’ (Caledonian Partnership, in prep.). The partners, which include the FC, SNH, and Highland Birchwoods, expect the latter to become an important source of information on Scotland’s semi-natural woodlands by mid- 2000. This information will complement the FC’s National Inventory of Woods and Trees (Wright, 1998) to provide a comprehensive picture of Scotland’s forest resource at the start of the new millennium. The methodology adopted allows links to be made to other data-sets, and the incorporation of additional details, including information on woodland condition, dependent species, and potential resource benefits, for example for timber or recreation.
Successful conservation of the Caledonian pinewoods may start with finding out what is there, but it is ultimately dependent on taking positive actions on the ground, coupled with steps to measure and monitor change as a result of these actions. Work is in progress to develop the data capturing systems used for WGS, because WGS underpins virtually all site-based operations in woodlands. This is seen as the most cost-effective and continuous way of recording what happens to the Caledonian pinewoods, and will be used in the same way for other native woodland habitats.
Acknowledgements
I wish to acknowledge the work of Graham Tuley in developing the Inventory from 1991-96 and to the many other people both within the FC and externally who have since then contributed towards the design and production of the Inventory in an easily distributable form using the modern tools of Information Technology. I am grateful to Graham Tuley and to Peter Quelch for their comments on earlier drafts of this article.
References
Aldhous J R (1995): (Editor) Our Pinewood Heritage. Proceedings of a Conference at Culloden Academy, Inverness 1994. Published jointly by Forestry Commission, The Royal Society for the Protection of Birds, Scottish Natural Heritage.
BSG (1995): Costed Habitat Action Plan for Native Pine Woodlands. Biodiversity: the UK Steering Group Report, volume 2, pp 259-261. HMSO.
Bain C (1987): Native Pinewoods in Scotland. A Review 1957-1987. RSPB, Edinburgh.
Bennett K D (I995): Post-glacial dynamics of pine (Pinus sylvestris, L) and pinewoods in Scotland. Our Pinewood Heritage. Proceedings of a Conference at Culloden Academy, Inverness 1994, (Ed. by J R Aldhous), pp 23-39. Published jointly by the Forestry Commission, The Royal Society for the Protection of Birds, Scottish Natural Heritage.
Bunce R G H and Jeffers J N R (1977): (Editors) Native Pinewoods of Scotland. Proceedings of Aviemore Symposium 1975. Institute of Terrestrial Ecology, Cambridge.
Caledonian Partnership (1997): Scotland’s Caledonian Forests: Resource Assessment and Implementation of a Restoration Programme for Glen Affric. Final LIFE-Nature Progress Report. Contract No. B4-3200I94I769. Highland Birchwoods, Munlochy.
Caledonian Partnership (in prep.): The Millennium Guide to Scotland’s Forest Resource. Highland Birchwoods, Munlochy.
Carlisle A (1954a): The morphological and silvicultural variation of the native Scots pine (P. sylvestris L) of Scotland. Unpublished thesis, University of Aberdeen.
Carlisle A (1954b): Variation in the native Scots pine of Scotland. Forestry Commission Report on Forest Research 1954, pp 55-56. HMSO.
Carlisle A (1956): The native Scots pine of Scotland. (Precis of a lecture by Dr A Carlisle to the Royal Scottish Forestry Society, Aberdeen Region). Scottish Forestry 10, p 165.
Carlisle A (1958): A guide to the named variants of Scots pine (Pinus sylvestris, Linnaeus). Forestry 31, pp 203-224.
EEC (1992): Directive 92/47/EEC. Conservation of Natural Habitats and Wild Flora and Fauna. European Commission, Brussels.
Forestry Authority (1994a): Caledonian Pinewood Inventory. (Unpublished) The Forestry Authority, Glasgow.
Forestry Authority (1994b): Caledonian Pinewood Inventory. Explanatory leaflet. The Forestry Authority, Glasgow.
Forestry Commission (1978): Native Pinewoods Grants. Leaflet. Forestry Commission, Edinburgh.
Forestry Commission (I989a): Grants for New Native Pinewoods. Leaflet. Forestry Commission, Edinburgh.
Forestry Commission (1989b): Native Pinewoods Grants and Guidelines. Leaflet. Forestry Commission, Edinburgh.
Forestry Commission (1991): Register of Native Pinewoods. (Unpublished) Forestry Commission, Edinburgh.
Forestry Commission (1999): The Caledonian Pinewood Inventory (1998). Forestry Commission, Edinburgh. [Available on a IBM 3.5″ floppy disk from the Forestry Commission National Office for Scotland, 231 Corstorphine Road, Edinburgh. EH 12 7AT]
Forrest G I (1980): Genotypic variation among native Scots pine populations in Scotland based on monoterpene analysis. Forestry 55, pp 1 0 1 – 128.
Guillebaud W H (1933): Scots pine in Morayshire and Strathspey. Forestry 7, pp 137-153.
Quine C P (1980): Scots Pine on the islands of Loch Assynt, South West Sutherland. Unpublished Honours thesis. Geography Department, Cambridge University.
Steven H M (1958): The native pinewoods of Scotland and their significance for current forestry practice. The Advancement of Science, xv, no. 59. p 340.
Steven H M (1961): The place of Scots Pine in Scottish Forestry. Scottish Forestry 15, pp 111-115.
Steven H M and Carlisle, A (1959): The native pinewoods of Scotland. Oliver and Boyd, Edinburgh.
Wright D (1998): The National Inventory of Woodlands and Trees. Forestry Commission Information Note no. 8. Forestry Commission, Edinburgh.
Letters, etc. 