Information and Advisory Note Number 125 Back to menu
NATURAL HERITAGE TRENDS
Land Cover 1947-1988: forests and woodlands
1. Broad leaved woodland
1.1 In an unaltered state Scotland would be mainly wooded, except on mires where
the ground is too waterlogged for tree growth and on mountain tops and coastal
margins where exposure imposes altitudinal and latitudinal limits. Brown earth
soils to the south of the Highland Boundary Fault would favour ash, Fraxinus
spp., and oak, Quercus spp., with pine, Pinus sylvestris, mainly colonising the
podzols and shallow peats to the north. Hardier hazel, Corylus avellana, rowan,
Sorbus spp., birch, Betula spp., and juniper, Juniperus spp., would extend to
the upper slopes, and to the north west.
1.2 That Scotland has become largely deforested is a legacy of land clearance
for agriculture since Neolithic times, around 5,000 years ago. By medieval
times,
1,000 years ago, much of the country was denuded of trees. Eighteenth century
coppicing of oak woods for charcoal and the natural tannin in oak bark gave
value to the preservation and management of broadleaved woodland. As those
commercial uses fell away in the nineteenth century, so too the oak woods fell
into neglect.
1.3 The term 'broadleaved woodland' here
encompasses true native woodlands as well
as eighteenth and nineteenth century
plantings, including woods of non-native
sycamore and beech. The extent of mixed
woodland is estimated to have been about
one-third that of broadleaved woodland.
2. Trends
2.1 Over 41 years, between c.1947 and c.1988, the area of broadleaved and mixed
woodland in Scotland is estimated to have declined by 26%: a mean annual rate of
13 kmē.
2.2 About half of the reduction in the area (284 km2) was due to replacement by
conifer plantation forest. The remainder was mainly cleared or allowed to open
out into rough grassland, bracken or scrub. When canopy cover fell below 50%,
woodland was reclassified as 'parkland', indicating a transitional stage in a
thinning cover.
2.3 Small areas (amounting to 26 km2 or 5% of the overall reduction) were
enveloped by expanding urban boundaries.
2.4 Reductions in broadleaved woodland cover occurred throughout its range.
2.5 Overall, broadleaved woodland is estimated to have contracted from around
2,100 km2 in the 1940s to 1,500 km2 in the 1980s.
3. Coniferous Woodland
3.1 Although geographically isolated, the native pinewoods of Scotland are an
integral part of a much more extensive and complex pattern of woodland variation
across Eurasia. Lying beyond the natural western limit of Norway spruce, the
distinctive and diverse floristic character of native pinewoods is influenced
both by the oceanic climate of the Atlantic seaboard and by a boreal climate
towards the east, similar to that of northern-continental Scandinavia. Relative
to other tree species, Scots pine performs best on highly impoverished, sharply
draining soils. At lower altitudes and on more fertile soils, competition and
co-dominance with oak and birch are the norm. True native pinewoods occur only
in mainland Scotland north of the Highland Boundary Fault, but small areas of
coniferous woodland which are semi-natural in character are to be found
elsewhere in Scotland.
3.2 Many of the eastern pinewoods were actively managed and sustained for timber
production in the eighteenth and nineteenth centuries. Cheap imports of
Norwegian, Swedish and Baltic softwoods subsequently displaced domestic timber
production. As pinewoods were turned over to sport or pasture, natural
regeneration became suppressed by the browsing of deer, cattle, goats and sheep.
Remnant stands of native Scottish pinewoods, albeit fragmented and
scattered, are of very great conservation importance in terms of their species
composition, structure and scenic character.
4. Trends
4.1 Over 26 years, between c. 1947 and c.1973, the area of native pinewood is
estimated to have declined by half, at a mean annual rate of around 4 kmē.
4.2 The decline was arrested by the 1970s, and from c.1973 to c.1988 the area of
remaining coniferous woodland was unchanged.
4.3 Conversion to conifer plantation was the main cause of native pinewood
decline (from the 1940s to the 1970s).
4.4 Small areas were also cleared or allowed to degenerate into grassland.
Countering that influence on the area of coniferous woodland, small areas of
mixed broadleaved woodland changed in character to become more pine-dominant.
4.5 Coniferous woodland, highly restricted in extent, was reduced throughout its
range. Small areas of coniferous woodland (as well as small areas of mixed
woodland) were also reduced in the far south.
4.6 Overall, coniferous woodland is estimated to have contracted from around 200
km2 in the 1940s to 100 km2 by the 1980s.
5. Coniferous Plantation Forest
5.1 The industrial revolution gave impetus to afforestation (partly based on
European species of larch, Larix spp., and Norway spruce, Picea abies) in the
late eighteenth century. North American species of Sitka spruce, Picea
sitchensis, and Douglas fir, Pseudotsuga menziesii, were introduced in the
nineteenth century. Nevertheless, in the face of cheap timber imports from
Europe and Canada, afforestation failed to develop as widely in Britain as in
Continental Europe. Thus, by the outbreak of the First World War, only around 5%
of the land area was under tree cover and domestic timber production accounted
for less than one-tenth of national needs. With inter-war plantings still
immature at the outbreak of the Second World War, which again resulted in heavy
felling, action was required to re-stock and extend the forest area.
5.2 The Forestry Act of 1945 gave stimulus to private and public planting.
Expansion was directed mainly into the uplands to minimise competition with
agriculture. Peatlands became suitable for afforestation through the development
of ploughs that enabled them to be drained; the Cuthbertson plough in the 1930s
and the 'humpy' plough in the 1960s.
5.3 The planting programme was sustained by demand for timber, chipboard and
pulp, and notably from the Fort William pulp and paper mill which opened in the
1960s. Natural heritage concerns, coupled with public unease over tax
arrangements, contributed to the removal of forestry from the scope of Income
Tax and Corporation Tax relief in the March 1988 budget. Thereafter, the scale,
structure and species composition of private planting was influenced through a
new Woodland Grant Scheme.
6. Trends
6.1 Over 41 years, between c.1947 and c.1988, the area of
coniferous plantation forest in Scotland is estimated to have expanded by 610%,
a mean annual increase of about 190 kmē
6.2 Afforestation took place mainly on upland habitats: about 31% was on blanket
mire, 30% was on rough grassland and 28% was on heather moorland.
6.3 Long-established and semi-natural woodland was also converted to plantation
forest.
6.4 A range of smaller changes accounted for the rest.
6.5 Apart from the Outer Isles, where land capability for forestry is highly
restricted, afforestation took place throughout Scotland. It occurred on a large
scale throughout the Highlands and Southern Uplands, and especially so in the
south and parts of the west.
6.6 Overall coniferous plantation, commonly of dense, even-aged stands of exotic
species, increased from around 1,300 km2 in the 1940s to 9,200 km2 in the 1980s.
7. Source
7.1 Statistical estimates are from the 'National Countryside Monitoring Scheme',
a sample survey which interpreted air-photography representing 7.5% of
Scotland's land area (Mackey et a/., 1998). Although sampling is not optimal for
this purpose, change in extent is mapped here according to the 21 Natural
Heritage Zones.
7.2 The geographical distribution of the habitat was mapped using the nearest
equivalent features from the Land Cover of Scotland 1988 dataset (MLURI, 1993).
8. References
Macaulay Land Use Research Institute (1993).
The Land Cover of Scotland 1998:
Final Report. Aberdeen: MLURI.
Mackey, E.C., Shewry, M.C. and Tudor, G.J. (1998).
Land Cover Change: Scotland
from the 1940s to the 1980s. Edinburgh: The Stationery Office.
9. Further Information
Further information on other topics covered by Natural Heritage Trends: Land
Cover 1947-1988 can be found in Information & Advisory Note No. 123.
10. Contact
To obtain further information about any of the issues raised in this l&A Note,
please contact
Mr Ed Mackey and Mr Mike Shewry
Environmental Audit Group
Chief Scientist's Unit
Scottish Natural Heritage
2 Anderson Place
Edinburgh
EH6 5NP
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