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Abstract

  1. Top of page
  2. Abstract
  3. SOURCES OF INFORMATION
  4. DEVELOPMENT OF THE FOREST RESOURCE SINCE 1945
  5. DEVELOPMENTS IN SILVICULTURE
  6. MARKETS AND MANAGEMENT
  7. FUTURE ISSUES
  8. REFERENCES

The last half-century has been an era of historically unprecedented expansion in British forests, which now cover over 12% of the land surface. In the immediate post-War period, the forest composition was evenly divided between conifers and broadleaves. However, several decades of extensive afforestation in parts of the uplands have resulted in conifers comprising over 60% of the forest area and Sitka Spruce Picea sitchensis becoming the commonest species in British forests. Towards the end of the last century, forestry policies began to give prominence to sustainable forest management so that greater emphasis is now being given to aspects such as the restoration and enhancement of native woodlands and the diversification of plantation forests. Because of their age structure, at least 70% of both conifer and broadleaved high forest stands are now entering a closed-canopy stage where the trees compete with each other for light, moisture and nutrients. This is different from the situation in the late 1940s when the appreciable area of young stands in both new woodlands or felled areas would have provided a more open woodland habitat. The prevailing silvicultural system used for many years in all high forest types has been ‘patch clear felling’ but this can be detrimental to visual amenity and cause a sudden change in forest microclimate. There is now increasing interest in the use of continuous cover forestry, which seeks to promote irregular stand structures with intimate species mixtures as a means of avoiding some of the negative impacts of clear felling. Timber production in British forests is increasingly concentrated in the conifer forests and the amount of broadleaved timber harvested has declined sharply in recent years. This decline is another consequence of the lack of active broadleaved management that has been reported in recent ecological surveys. The possible advent of a new woodfuel market may be an opportunity to renew the viability of under-managed woodlands. The next decades are likely to see a greater range of silvicultural systems being practised in British woodlands and the development of more mixed woodland, which may also ensure greater resilience against climate change. Amongst the challenges for the future are the need to obtain a better understanding of the interactions between stand management, resulting forest habitat and the impacts on biodiversity so that foresters and other stakeholders can better predict the outcome from different silvicultural regimes.

The 20th century was a period of considerable change in the extent and management of forests in Britain, which is probably unprecedented in historical times. At the beginning of the century the forest area of Britain was around 5% of the land area (Richards 2003). This low figure by European standards was the consequence of a process of deforestation that had started centuries earlier (Rackham 1986, Smout 2003). However, in many cases the surviving woods and forests showed substantial continuity with the past. Rackham (1986) considered that, in 1910, there were thousands of woodlands in Britain that had been little changed for some 650 years, even if most had been actively managed using a range of coppice and coppice-with-standards systems. A variety of products were provided ranging from small dimensioned wood products for local users to larger sized timber for a variety of heavy industries. Towards the end of the 19th century, managers started to increase the amount of timber trees in the overstorey of coppice woodlands at the expense of the underwood in response to changing market conditions and, in particular, the decline in demand for small sized material (Rackham 1986). At the same time, there was increasing interest in the practices of even-aged plantation forestry, formulated in the forestry schools of France and Germany, which sought to produce large volumes of uniform dimension timber for sawmills and other wood-using industries. This interest was shown by the planting of non-native timber trees in existing woodlands and by the establishment of extensive plantations on marginal agricultural land, most notably in parts of Scotland such as the Atholl estates in Perthshire (House & Dingwell 2003).

Following the formation of the Forestry Commission in 1919 and the primacy given to the objective of creating a strategic reserve of timber, considerable emphasis was placed on the expansion of the forest area using plantation forests based upon fast growing conifers (Richards 2003). This resulted in an era of major afforestation from 1950 until the late 1980s when the concepts associated with even-aged plantation silviculture dominated forestry thinking. The same period saw the almost complete cessation of traditional coppice management systems in many woods, which was the culmination of a decline begun in earlier decades. This was often combined with an attempt to convert the stands to a regular structure, either by allowing the coppice to develop into a closed-canopy broadleaved high forest or by the introduction of non-native conifers (Rackham 1986) with consequent losses of biodiversity and amenity value. The strategies of converting native woodlands to conifer plantations and of large-scale afforestation of marginal upland areas (e.g. the ‘Flow Country’ of northern Scotland) proved increasingly controversial (Avery & Leslie 1992), and substantial changes in policy occurred during the last two decades of the century. A broadleaves policy was introduced in 1985 (Richards 2003), which essentially ensured that no further broadleaved woodland would be converted to conifers. In 1988 changes to the tax rules that had underpinned private forestry substantially reduced the amount of conifer afforestation (Foot 2003). These changes were followed in the 1990s by an increasing emphasis on the principle of sustainable forest management (SFM) for multiple benefits (often referred to as ‘multi-purpose’ forestry). This process began at the 1992 United Nations Conference on Environment and Development (UNCED) in Rio de Janeiro and developed into European guidelines at the 1993 Helsinki Ministerial Conference. In 1998, these guidelines were formulated in the UK Forestry Standard (Anon. 2004), which outlines the desired conditions for the interaction between forest management and four basic aspects of the forest ecosystem (physical, biological, human and cultural). The development of the UK Standard resulted in a voluntary certification standard for the forest sector (the United Kingdom Woodland Assurance Standard; UKWAS 2000) being established following extensive consultation between the industry and a wide range of stakeholders (Cashore et al. 2003). UKWAS was recognized by the non-governmental Forestry Stewardship Council (FSC) in 1999 and the FSC label is increasingly used on British forest products, while increasing areas of forest, including all Forestry Commission managed properties, have achieved certification under UKWAS (Mason 2007). In practice, certification is primarily applicable in woodlands where timber production is an objective of management and is of lesser importance elsewhere.

As a result of the changes of the last 20 years and the increasing emphasis upon SFM, there has been a move away from the plantation management approach that has dominated British forestry. There is increasing recognition of the benefits provided by appropriate management of native woodland types, such as Caledonian pinewoods (Mason et al. 2004), and of the desirability of restoring native woodland communities where conifer plantations were established on ancient woodland sites (Thompson et al. 2003). The desirability of increasing the area of forest that is managed to produce quality broadleaves has been strongly promoted (Worrell et al. 2004). Both the Scottish (Anon. 2000) and Welsh (Anon. 2001) woodland strategies have endorsed the desirability of greater use of continuous cover forestry (CCF) whereby more irregular stand structures with a range of intermixed species are developed. The Welsh strategy includes an aspiration that half the Forestry Commission woodlands should be converted to CCF by 2020.

The aim of this paper is to review the present age structure and composition of British forests and to show how the resource and silvicultural practices have changed over the last 50 years. This period was selected because it covers the era of greatest change in forest cover and is also one for which there are reasonable data on the forest resource. This long-term perspective is essential because forests can take several decades to respond to changes in management and the habitats that they provide today are often a function of decisions made years ago. The influence of different stand management strategies is considered, as well as present and future markets for wood products. A number of issues are highlighted where better understanding of the impacts of management upon forest habitat would improve our ability to sustain and enhance bird populations.

SOURCES OF INFORMATION

  1. Top of page
  2. Abstract
  3. SOURCES OF INFORMATION
  4. DEVELOPMENT OF THE FOREST RESOURCE SINCE 1945
  5. DEVELOPMENTS IN SILVICULTURE
  6. MARKETS AND MANAGEMENT
  7. FUTURE ISSUES
  8. REFERENCES

The best sources of data for assessing the changes in British forests since World War Two are those provided by the periodic national censuses of woodlands carried out at approximately 15-year intervals (Smith & Gilbert 2003). There have been four such censuses since 1945; the first published in 1947 shows the state of woodlands after a period of intense exploitation to support home industries during the War; the second (1965) and third (1982) show British forests in the early and later stages of the afforestation era; the most recent (2000) follows the abandonment of large-scale afforestation and the move towards multipurpose management. The sampling methods and classifications differed somewhat between censuses but these should not affect the validity of using the data to determine national trends in the development of the resource (G. Bull, Forest Research, pers. comm.).

Further information on changes in woodland habitat in Britain can be obtained by examining the distribution of age classes in the conifer and broadleaved high forest types in the four post-War censuses. The method of presenting age class data varied slightly between censuses but generally used 10-year age classes from the census date back to 1900 and 20–40-year classes for older stands. To simplify the data, these age classes were summarized into four groups, namely < 15 years of age, 15–50 years, 51–100 years, and > 100 years. Where a census age class interval was different from that of one of these groups (i.e. < 15 years), proportionate adjustments were made. The reason for using four groups was that these can be linked to the four phases of stand development that form the basis of a widely used model of forest stand dynamics (Oliver & Larson 1996). Thus, stands less than 15 years old are typically in the ‘stand initiation’ phase, those 15–50 years represent the ‘stem exclusion’, 51–100 years characterizes the ‘understorey reinitiation’ phase, and those older than 100 years are entering the last phase termed ‘old growth’. In brief, the first phase covers the period when trees are establishing on a site and have not formed a canopy so that grasses, forbs and other vegetation are still present. In the stem exclusion phase, the trees have formed a continuous canopy and compete with each other for light, moisture and nutrients. Ground vegetation only persists if the canopy trees allow sufficient light to penetrate to the forest floor. In the third phase, the canopy starts to open up as a result of self-thinning and other processes, light levels within stands increase, and tree saplings and woody shrubs can colonize and develop in the understorey. Old growth stands are characterized by substantial canopy gaps, groups of saplings that regenerated in the previous phase now reaching the canopy, and appreciable numbers of standing dead mature trees.

The importance of changes in age and stand structure mediated by forest management as an influence on woodland habitat for birds is emphasized in recent surveys (Amar et al. 2006). However, it is important to recognize that stand age is only a crude surrogate for development phase, as this can vary with species, site fertility and management history. The problems of defining development phases correctly are particularly acute in older stands and especially the old growth phase (Frelich 2002). For instance, Mason et al. (2004) suggest that in Scots Pine Pinus sylvestris forests the understorey reinitiation phase may last until 80 years and old growth may not develop until 150 years or later.

DEVELOPMENT OF THE FOREST RESOURCE SINCE 1945

  1. Top of page
  2. Abstract
  3. SOURCES OF INFORMATION
  4. DEVELOPMENT OF THE FOREST RESOURCE SINCE 1945
  5. DEVELOPMENTS IN SILVICULTURE
  6. MARKETS AND MANAGEMENT
  7. FUTURE ISSUES
  8. REFERENCES

During the second half of the last century the forest area of Great Britain (Table 1) has more than doubled so that the percentage forest cover is approaching 12% of the land area. Cover is highest in Scotland at 17% and lowest in England at about 8.5% (Forestry Commission 2005). This expansion has also resulted in the development of extensive forests in parts of the country where for several centuries there has been little or no tree cover. There have also been appreciable changes in species composition over this period as the conifer high forest component is now a much higher proportion of the total area than was the case in the immediate post-War period (Table 1). The balance of species also varies by country: conifers form nearly 90% of the forest area in Scotland, compared with a much lower proportion in England. One other feature evident from Table 1 is the considerable decline in the area of broadleaved woodland managed under coppice or coppice-with-standards regime in the post-War period.

Table 1.  Development of the forest area (’000 ha) of Great Britain by main forest type over the period 1945–2000. Percentage figures are given in parentheses. Source: Forest Research, Woodland Surveys.
Census yearHigh forest
ConiferBroadleavedCoppiceCoppice-with- standardsFelledTotal
  1. Note the figures for 2000 exclude 216 665 ha of ‘open ground’ within forests that was not identified as a separate category in previous censuses.

1947 382.4 (41)341.5 (37)48.6 (5)93.0 (10)61.1 (7) 926.7
1965 917.3 (67)349.8 (25)16.5 (1)10.3 (1)78.3 (6)1372.1
19821321.0 (67)560.3 (29)27.6 (1)11.6 (1)39.8 (2)1960.2
20001379.5 (59)880.7 (38)12.7 (1)10.8 (< 1)47.0 (2)2330.8

The area of all the major conifer species has increased as a result of this expansion. However, the balance of species within the conifer high forest has changed dramatically, since Sitka Spruce Picea sitchensis is now the dominant species in the conifer high forest type with the 2000 figure of some 683 000 ha comparing with only 67 000 ha in 1947. By contrast, Scots Pine, which was the major conifer species in 1947 (147 000 ha) and 1965 (252 000 ha) has shown a relative decline to 219 000 ha at the end of the century. This change reflects the greater productivity and lesser site sensitivity of Sitka Spruce on the wetter soils of western and upland Britain that were the centre of much of the afforestation effort in the post-War period (Zehetmayr 1954, 1960). One consequence of the wider use of Sitka Spruce and other conifers (e.g. Douglas Fir Pseudotsuga menziesii, Western Hemlock Tsuga heterophylla and various silver firs Abies spp.) is that all these species cast appreciable shade during the stem exclusion phase. By contrast, species which cast a lighter shade (pines, larches) are relatively less prevalent than in 1945, even if they are common in certain regions (e.g. northeast Scotland, the Breckland forests of East Anglia). In the broadleaved high forest, most species have shown an increase in area but birches Betula spp., Ash Fraxinus excelsior and ‘other broadleaves’ have assumed a relatively greater importance within this type (Table 2). The increases in birch- and ash-dominated woodland are particularly evident in the 1982 and 2000 data and may reflect the ability of these species to colonize felled areas or neglected coppice woods. The area of oak Quercus spp.-dominated woodland has slightly increased over the last half century (from 174 000 to 206 000 ha) while Beech Fagus sylvatica woodlands have shown little change (from 65 000 to 76 000 ha). One aspect not shown in the data is the major decline in elm Ulmus spp. within the ‘other broadleaves’ category from 1965 onwards as a consequence of Dutch elm disease (Evans 1997). This will also have resulted in a short-term increase in the amount of deadwood, particularly in lowland broadleaved woodlands (Fuller et al. 2005).

Table 2.  Area (’000 ha) and percentage (parentheses) change in the species composition of the High Forest type in Great Britain from 1945 to 2000 (source: Forest Research, Woodland Surveys).
Species1947196519822000
Pinus sylvestris147.3 (20)252.3 (20)241.0 (13)219.4 (10)
Pinus nigra var. maritima15.6 (2)36.7 (3)47.3 (3)45.4 (2)
Larix spp.78.5 (11)146.6 (12) 151.8 (8)130.2 (6)
Picea sitchensis67.6 (9)247.8 (20) 525.9 (28)683.7 (30)
Pseudotsuga menziesii15.3 (2)43.1 (3)47.4 (3)45.2 (2)
Other conifers58.0 (8)190.7 (15)307.6 (16)255.7 (11)
All conifers382.4 (53)917.3 (72)1321.0 (70)1379.5 (61)
Quercus spp.174.6 (24)166.2 (13)172.0 (9)206.2 (9)
Fraxinus excelsior34.3 (5)39.8 (3)69.6 (4)110.2 (5)
Fagus sylvatica65.6 (9)65.9 (5)73.9 (4)76.6 (3)
Betula spp.27.2 (4)31.5 (2)68.1 (4)76.6 (7)
Acer pseudoplatanus22.7 (3)26.4 (2)49.4 (3)61.4 (3)
Other broadleaves17.2 (2)19.9 (2)127.2 (7)262.0 (12)
All broadleaves341.5 (47)349.8 (28)560.3 (30)880.7 (39)

From the age-class analysis (Table 3), we can see that in 1947 the conifer high forest was composed mainly of trees in the two younger groups, while the situation in the broadleaved forest was the reverse with a predominance of the two older groups. The conifer high forest had a high proportion of stands in the initiation phase in 1965 as a consequence of upland afforestation. The area in this category was still high in 1982 but there was a progressive decline thereafter towards 2000 as more stands entered the stem exclusion category. The striking feature of the most recent conifer forest data is that 77% of the resource is in the stem exclusion phase. As many of these stands will be ready for harvest in the next 20 years, decisions on their future management could have a major impact on the type of future forest habitat available for wildlife. Older conifer stands have been a small component of British forests throughout the last 50 years. The trends in the broadleaved type show a slight increase in the extent of stands in the youngest initiation phase by 2000, but the major difference is the increase in the amount and proportion of stands in the stem exclusion and understorey reinitiation phases. An additional factor is that an appreciable percentage of the area of coppice and coppice-with-standards stands identified in 1947 (Table 1), and not considered in Table 3, would probably have been worked during the War and so would have had stand initiation characteristics at that time. Therefore, one important feature of the development of British forests over the last 50 years has been the move from a resource with a comparatively high proportion of young and old stands, towards one which is dominated by stands in the closed-canopy stem exclusion and understorey reinitiation phases.

Table 3.  Area (’000 ha) of conifer and broadleaved high forest by four age class groups and percentage distribution (parentheses) for census dates from 1947 to 2000 (source: Forest Research, Woodland Surveys).
Forest typeCensus date< 15 years15–50 years51–100 years> 100 years
Conifers1947147.9 (39)157.7 (41)52.0 (14)24.7 (6)
1965529.7 (58)320.4 (35)47.4 (5)19.8 (2)
1982512.1 (39)697.3 (53)94.6 (7)17.0 (1)
2000219.5 (16)1067.8 (77)73.0 (5)19.1 (1)
Broadleaves194712.4 (4)37.0 (11)154.4 (45)137.7 (40)
196534.9 (10)54.4 (16)148.2 (42)112.3 (32)
198236.4 (6)209.2 (37)191.7 (34)122.9 (22)
200057.9 (7)269.6 (31)376.9 (43)176.3 (20)

DEVELOPMENTS IN SILVICULTURE

  1. Top of page
  2. Abstract
  3. SOURCES OF INFORMATION
  4. DEVELOPMENT OF THE FOREST RESOURCE SINCE 1945
  5. DEVELOPMENTS IN SILVICULTURE
  6. MARKETS AND MANAGEMENT
  7. FUTURE ISSUES
  8. REFERENCES

Conifer forests

Pre-War research, complemented by improved cultivation machinery (Zehetmayr 1960), had provided foresters with a robust set of silvicultural techniques to establish conifer plantations on a range of sites that had been considered unplantable at the beginning of the 20th century. The focus upon maximum wood production at least cost (Malcolm 1997) resulted in the use of intensive site manipulation to reduce the stand initiation phase so that canopy closure was achieved as quickly as possible (Davies 1979). Fast growing species with high volume production such as Sitka Spruce were preferred wherever possible so that the resulting forests had little species diversity. Increasing awareness of the risks of wind damage to plantations on shallow soils in exposed upland areas led to the progressive adoption of no-thinning regimes in many areas (Quine et al. 1995). This strategy proved an attractive option in difficult market conditions and/or in forests remote from end-users. The lack of thinning prolonged the stem exclusion phase where the limited light below the canopy (Hale 2005) would restrict both regeneration and understorey vegetation. The main silvicultural system employed in nearly all British conifer forests for much of the last century was one of ‘patch clear-felling’ (Matthews 1989) stands when the trees had reached economic maturity followed by replanting. Discounted cash flow techniques and stand yield tables (Johnston et al. 1967, Edwards & Christie 1981) were used to determine felling ages, which for most conifer species tended to be in the region of 40–60 years, depending upon growth rate and the risk of windthrow.

Hibberd (1985) described the application of the patch clear-felling system in the spruce-dominated forests of the English–Scottish border, where the main concessions to other objectives were reducing the size of the felled area in more conspicuous areas and the introduction of a percentage of broadleaves into the restocking. This system did create greater variation at a landscape scale through the ‘restructuring’ process whereby extensive areas of single aged stands were broken up through felling into smaller units of different ages, so increasing between-stand variation. However, there were few structural features such as large veteran trees, gaps, and standing and fallen deadwood which are beneficial to biodiversity and attractive to visitors (Peterken et al. 1992, Humphrey et al. 2003). The ultimate consequence was the creation of simple forests largely composed of stands in the stand initiation and stem exclusion phases with little within-stand structural diversity.

By the early 1990s, several factors had combined to make the use of alternative silvicultural systems more interesting to managers. These included the increasing maturity of many conifer stands resulting in greater frequency of natural regeneration (Malcolm 1997), which offered the chance of reducing costs involved in restocking. There was also greater awareness of the negative visual impact of even well-designed clear felling, and a desire to maintain mature conifer woodland habitat that was attractive to the public, especially in areas used for recreation. Managers began to recognize that a different system to patch clear felling might be better suited to meeting objectives, especially in locations where non-market aspects such as landscape and amenity were important. This led to increasing interest in the CCF approach, which involves a number of principles such as avoidance of clear felling, working with natural processes such as natural regeneration, and development of mixed stands of irregular structure (Mason et al. 1999, Pommerening & Murphy 2004). These principles can be implemented using alternative silvicultural systems described in Europe for nearly two centuries (Matthews 1989), but largely ignored in Britain for much of the post-War period (Hart 1995). All are characterized by the progressive thinning of a mature stand coupled with retention of some overstorey trees to act as a seed source for natural regeneration and also to provide an element of shelter for the regenerated seedlings. Thus, successful implementation of these systems involves the movement of a stand from the stem exclusion phase to that of understorey reinitiation with a consequent increase in structural diversity. In some methods, like various seed tree and shelterwood systems, the mature trees are normally felled once the regeneration is satisfactorily established, so that the resulting stand is essentially regular and even-aged. However, it is possible to retain some of the mature trees for another rotation to provide greater structural diversity. These systems were used on some scale on private estates in the eastern native pinewoods of Scotland in the first part of the last century, as is evident from descriptions and photographs in Steven and Carlisle (1959). They appear to have been abandoned in the 1950s, partly because the 1953 storm removed large numbers of retained trees and thus eliminated the seed source, but also because the system was deemed too complicated to fit within the constraints imposed by the woodland grant schemes of the time (D.B. Paterson pers. comm.).

Other alternative systems, often termed selection or group selection, are based upon the approaches developed in the mixed irregular forests of the mountains and foothills of central Europe dominated by beech, Norway Spruce Picea abies, and European Silver Fir Abies alba (Matthews 1989). These species are all shade bearers and regenerate under the mature canopy, so that the natural structure is one of stands containing trees of all sizes, and ages, in an intimate mixture and with several storeys within the one stand. Silviculture of such forests gives less attention to the establishment of regeneration, provided adequate seedling numbers are present, and concentrates on fostering a structure where all tree sizes are present in a desired ratio. The nature and utility of this ratio is much discussed in the forestry literature (Kerr & O’Hara 2000 and references therein) but the spatial structure of selection stands managed according to such ratios is very different from the regular patterns characteristic of plantation forests (Pommerening & Murphy 2004). The selection systems also differ in that a greater range of product sizes are harvested at any one time, and that there is an explicit focus upon the production of large diameter trees of high timber quality. Anderson (1960) first proposed the possibility of transforming conifer plantation forests in Britain by the adoption of selection systems, but the approach found little favour at a time when conifer afforestation was at its height.

Uptake of CCF was given further stimulus by the certification process (see earlier) and especially the requirement of the UKWAS protocol that ‘in windfirm conifer plantations, lower impact silvicultural systems are increasingly favoured’ (UKWAS 2000). This has resulted in an almost ten-fold increase in the area of Scottish conifer forests designated for CCF management (Mason 2003). A feature of CCF forests compared with many plantations, especially those managed on non-thin regimes, is that regular thinning is essential to develop a more stable stand structure and a suitable environment for the development of regeneration (Malcolm et al. 2001). As a consequence CCF stands are characterized by a wider range of tree sizes including more big trees with deeper crowns and there is greater diversity of vertical and horizontal structure than in a regular stand. Such variation might also be expected to provide wider biodiversity benefits (Kerr 1999), although the evidence for this is still limited (Quine et al. 2004). Furthermore, greater use of CCF will still take several decades to achieve substantial alteration in forest structure. For instance, the trial at Glentress forest near Peebles that was started by Anderson in the 1950s has not yet completed the transformation to the desired irregular condition after 50 years (Wilson et al. 1999).

Broadleaved forests

Evans (1997), in a review of developments in British broadleaved silviculture, referred both to the poor quality of many broadleaved woodlands in the pre- and immediate post-War periods and to a lack of interest in these species that continued at least until the early 1970s. This period also saw the planting of conifers in many broadleaved woodlands as part of an attempt to increase their productivity and to convert their structure to conform to the prevailing plantation silviculture ‘paradigm’ (Rackham 2003). The collapse of markets for small dimension roundwood discussed earlier saw a progressive abandonment of coppice management with a loss of the ‘woodmanship’ skills that had supported traditional broadleaved forestry (Rackham 2003). The patch clear-felling system has also been the main one employed in broadleaved high forests, the major difference from conifer forests being the much smaller size of the felled area (Evans 1984). Planting has traditionally been used to restock felled broadleaved woodlands given that natural regeneration has proved difficult, in part because of weed competition on more fertile soils often compounded by heavy browsing by deer (Harmer 2001).

The renewed interest in broadleaved management that followed the adoption of the broadleaves policy in the 1980s (Richards 2003) has seen appreciable increases in the proportion of broadleaved planting enhanced by the adoption of improved protection methods, such as treeshelters (Potter 1991), and more effective weed control regimes and increased grant aid. However, arguably the tending of stands that have closed canopy (stem exclusion phase) has not advanced, partially as a consequence of the bark stripping damage that can be caused to broadleaves by the Grey Squirrel Sciurus carolinensis (Mountford 1997), but also because of ongoing difficulties in marketing small sized timber. There have been some attempts to develop methods of more dynamic tending of broadleaved stands such as ‘free-growth’ regimes in oak (Kerr 1996), but these do not appear to have been widely adopted, and the general impression is one of less frequent thinnings in broadleaved woodlands in the last 10–15 years. The low levels of recent management recorded by Kirby et al. (2005) in a repeat survey of broadleaved woodlands provide support for this argument.

Although Hart (1995) cites some examples of the use of CCF systems in broadleaved woodlands, these appear to be less systematic both in approach and in scale than recent initiatives in the conifer forests. This may partly reflect perceived difficulties in obtaining natural regeneration (Harmer 1994), but also the browsing pressure exerted by rabbits Oryctolagus cuniculus, deer and other small mammals upon any seedlings that emerge. Arguably greater use of the thinning regimes designed to favour selected stems which are an integral part of CCF silviculture (Bruciamacchie & Turckheim 2005) could help improve stand quality and the financial attractiveness of greater management of broadleaved woodlands. There has been some revival of coppice management in the last 20 years or so, especially in woods managed for conservation purposes (Rackham 2003). However, it seems unlikely that this traditional system will ever be used on the scale of the pre-War period and earlier centuries unless a new bulk market is developed which can absorb substantial volumes of small dimension timber.

MARKETS AND MANAGEMENT

  1. Top of page
  2. Abstract
  3. SOURCES OF INFORMATION
  4. DEVELOPMENT OF THE FOREST RESOURCE SINCE 1945
  5. DEVELOPMENTS IN SILVICULTURE
  6. MARKETS AND MANAGEMENT
  7. FUTURE ISSUES
  8. REFERENCES

It is evident from the previous sections that forest management has been closely influenced by market conditions and, in particular, the prices paid to growers for the timber harvested. Thus, the collapse of the coppice industry that began in the late 19th century and continued through the first half of the last century was brought about by competition for small wood products from other materials (wire, plastics, etc.) (Aldhous 1997). It is striking to reflect that in 1927 the volume of broadleaved timber harvested in Britain was around double that of conifers (Guillebaud 1927, cited in Evans 1997). The situation is very different today, since in 2004 over nine million green tonnes of British conifer timber were produced for the market, compared with 510 000 green tonnes of broadleaved timber (Forestry Commission 2005). In addition only 18% of the broadleaved timber was destined for the more valuable sawmilling sector compared with about 53% of the conifer timber. The volume of broadleaved timber harvested has declined by about one-third since 1995, further indicating the degree to which there appears to have been a reduction in active management for timber in broadleaved woodlands in recent decades. This decline in harvesting activity in broadleaved woodland is a consequence of the historically low prices that have been paid in recent years for all but the top quality logs. This has resulted in owners withdrawing their timber from the market in the belief that there will be an upturn in prices in due course.

The conifer sector has been similarly exposed to low timber prices for at least a decade, and in 2004 sawlog prices were about 60% in real terms of what they had been in 1996. As a consequence, the returns from private sector investment in Sitka Spruce plantations in Scotland were negative between 1996 and 2003 (Mason 2007). However, despite the difficult trading conditions, increasing volumes of timber have been successfully brought to market, and new outlets have been developed including a sizeable export trade of conifer roundwood to Scandinavia. A modern and internationally competitive processing sector has developed around the conifer forest resource (Banks & Cooper 1997) and active forest management has continued, with strong linkage between growers and the market place. This has been helped by forest management regimes that are focused on a limited number of species and a few standard products.

In the conifer high forests, with the exception of sites with difficult access and/or in remote locations, the impact of low timber prices is more evident in the decision about how to restock sites after felling rather than in the harvesting. The policy drivers for restoration of native woodlands and greater awareness of the need to manage forests for a variety of functions, for instance through greater use of CCF regimes, will almost certainly reduce the extent of even-aged conifer stands in future. One recent estimate is that such factors might cause the area of conifer plantation in Scotland to decline by 20% or more by 2030 (Mason 2007), although the impact on timber flows may be offset by greater planting of higher yielding genetically improved material.

In both conifer and broadleaved woodland, a major issue confronting managers who wish to obtain some timber production from their woodlands is how to cover the costs of thinning the young and small dimension trees that are characteristic of the early stages of the stem exclusion phase. The wood from these trees is generally destined for a bulk market such as pulpwood or other low value end-use. The greater emphasis upon recycled fibre has resulted in a substantial decline in the pulpwood market and has been a further reason for under-management of woodlands, especially in the broadleaved forests. Recent estimates (Forestry Commission England 2006) suggest that there may be some 600 000 ha of under-managed woodland in England, of which at least 70% are likely to be broadleaved. The increasing interest in woodfuel as one means of providing a renewable energy supply in the face of climate change may yet provide a much needed market for the smaller dimension timber characteristic of young and under-managed woodlands (Hall & Jones 2005). Recent proposals suggest that two million tonnes per annum of wood could be supplied from under-managed woodlands for this re-emerging energy market (Anon. 2006).

FUTURE ISSUES

  1. Top of page
  2. Abstract
  3. SOURCES OF INFORMATION
  4. DEVELOPMENT OF THE FOREST RESOURCE SINCE 1945
  5. DEVELOPMENTS IN SILVICULTURE
  6. MARKETS AND MANAGEMENT
  7. FUTURE ISSUES
  8. REFERENCES

The previous sections show that we have entered the 21st century with a forest resource that is radically different from that which existed in the immediate post-War period. Not only has the forest area substantially increased but the species composition, the type of management, the balance of age classes, the habitats provided, the products being produced, the markets being served, not to mention the objectives of management have all changed over the course of the last half of the previous century. Changes in policy have recognized that the single objective silviculture based on high timber outputs with minimum costs which prevailed for much of the post-War period does not provide the desired species diversity and varied stand structures implicit in aspirations towards multipurpose forest management. A consequence is that we are likely to see a wider range of silvicultural systems being used in British forests in future, together with greater species diversity and appreciable variation in intensity of management. One probable outcome is that we shall move away from the divide between intensively managed conifer plantations and neglected remnants of native woodland that characterized discussions about forest management in Britain during the last half century. Instead, we shall aspire to a continuum of woodland types required to meet the needs of multipurpose management. However, there are at least five major issues that need to be considered as we try to develop our forests to meet this aspiration over the next decades.

Climate change

The first of these is the likely impact of climate change where increased temperatures, changing rainfall patterns and a possible greater frequency of severe storms can all be expected to influence future woodland management. For instance, on free-draining soils in southeastern Britain, greater evapotranspiration may result in more frequent summer droughts, which may place species such as beech under greater climatic stress (Broadmeadow & Ray 2005). Similarly, milder winters should lead to greater prevalence of insect pests such as the green spruce aphid Elatobium abietinum with consequently higher levels of defoliation of spruce trees and a possible reduction in yields (Straw 1995). Greater frequency of extreme storms such as those of 1953, 1968, 1976, 1987 and 1990 might reduce the potential for implementing CCF regimes in Britain, as thinning is critical in such regimes and recently thinned stands can be particularly vulnerable to wind damage (Mason 2002). Climate change may also bring benefits as more northerly regions may see improved growth as a result of longer growing seasons. There is still much that is uncertain about the future British climate but it is unwise to assume that past patterns of growth or species suitability will be maintained. Therefore, our forests should be managed to improve their ability to withstand changing conditions (Broadmeadow & Ray 2005). Amongst other aspects, greater fostering of mixed species stands should increase their resilience against extreme temperature or pest events, and appropriate thinning will provide individual stems with greater stability to withstand storms.

Timber production

The next factor is the impact of global trade in forest products upon the prices paid for and the demand for British timber. At present nearly 85% of the United Kingdom domestic demand for timber is met by imports (Thomson 2004). Therefore, British production has to compete with imported material in terms of price, quality and regularity of supply. Arguably the relative success of the conifer sector over the last decade has been due to the plantations of one or two major species such as Sitka Spruce providing adequate volumes with desirable wood properties to justify industrial investment. One danger of the pressure to diversify plantation forests is that this continuity of supply is disrupted so that the sector's international competitiveness is reduced. A perceived risk of greater use of CCF is that it may create appreciable amounts of large diameter (> 60 cm dbh) logs, which are outwith the size limits of existing harvesting and processing machinery (Macdonald & Gardiner 2005). The argument is not one of whether species and structure should be diversified, but rather how much diversification is necessary and at what scale? Restoring broadleaved woodlands to more active management seems to depend on finding adequate outlets for the amount of small sized material that is a natural by-product of the increasing area of stands in the closed-canopy stem exclusion phase. It is possible that new wood fuel initiatives may provide the desired outlets, but this will require greater co-operation between growers than has traditionally been the case in the broadleaved sector. Failing such new markets, it is possible that many broadleaved stands will go through periods of neglect, and cost-effective silviculture should seek to identify and foster those stems which have the potential to provide a quality product at some future date.

Impact of stand dynamics

One point that should be apparent from this paper is that forests take several decades to change, and current structures and species composition are often the result of policies that were promulgated several decades earlier. Thus, the simple structures of conifer plantation forests are the delivery of a policy of creating a strategic reserve of timber first defined after World War One (Richards 2003). Foresters respond to policies by designing and undertaking a set of actions, which are in turn designed to provide a set of forest conditions (structures) believed best to support the set of values or outputs desired by policy (Erdle & Sullivan 1998). The problem is that it takes time for actions to develop the desired condition and there is an imperfect understanding of the links between particular conditions and desired values. For instance, a decline in intensity of woodland management in lowland broadleaved woods has been considered as one factor influencing population changes in both birds and other biodiversity (Fuller et al. 2005, Kirby et al. 2005, Amar et al. 2006). However, the possible effects of declining management have to be considered against the background of a naturally ageing broadleaved resource (Table 3). A resumption of management, such as more frequent thinning or the use of small-scale clear fellings, will only reverse undesirable habitat changes if it is clear what future stand structure is appropriate. In a similar vein, the increased use of CCF is, in part, a response to criticism of the visual disruption caused by clear felling. However, there is a danger that over reliance on CCF could create forests without the views and changing landscapes that are a product of clear felling (Price 2003). It might also reduce the amount of open ground habitat within forests that are important for rare species such as woodlark Lullula arborea and nightjar Caprimulgus europaeus (Symes & Currie 2005), which need a minimum patch size of open habitat to occur (Ravenscroft 1989).

Future forests

The need for a better understanding of the links between different forest conditions and desired values indicates that foresters and their stakeholders must develop better methods to explore the impacts of management scenarios upon future outcomes. Interactive decision support tools (Seeley et al. 2004) can facilitate better stand- and forest-level planning techniques that explain to stakeholders how different actions may shape future structures. In this way it should be possible to arrive at a shared view on the desired future forest condition some 30–50 years hence and the actions to be taken to achieve this. This approach should cover all major forest types including conifer plantations as well as native woodlands as is partially done within the Ecological Site Classification (Pyatt et al. 2001). One might envisage that, in future, all plantation forests will include a percentage of stands in the understorey reinitiation and old growth stages as has been proposed for the native pinewoods (Mason et al. 2004). Regular monitoring of key parameters of the forest and woodland ecosystem, for instance evaluating the potential impact of deer browsing, would be undertaken to ensure that actions were having the anticipated impact on moving the forest towards a desired future condition.

Research

Lastly, more integrated research is needed to provide better insights into the effects of silvicultural regimes on different aspects of biodiversity, as well as on the other non-market objectives of management. There has probably been insufficient research undertaken to examine the biodiversity present in conifer plantation forests that are now such an important feature of the upland British landscape. Even for birds, studies have tended to be limited to stands in the initiation or stem exclusion phases (Bibby et al. 1985, Patterson et al. 1995), often with a focus on the effects of afforestation (Moss 1979). This is unfortunate given that there are reports showing the potential benefits to be obtained from older stands (Currie & Bamford 1982). Chronosequence studies have suggested that important fungal and invertebrate communities can be also found in the older stands in plantations (Humphrey et al. 2003), but how these may be affected by different management practices is unclear. The suite of some ten field-scale CCF trials being implemented in a range of British forests (Mason et al. 2005) offer an opportunity to carry out long-term studies of the response of different organisms to changing management practices and resulting stand structures. Similar investigations are also desirable in broadleaved woodlands under changing management scenarios. The assessments of stand structure should be linked to modern theories of stand dynamics (Oliver & Larson 1996, Frelich 2002) and be aware of new methods of quantifying spatial pattern within forests (Pommerening 2002). Such integrated studies are essential if we are to provide guidance on appropriate regimes that may foster better habitats for vulnerable bird species and other biodiversity.

The knowledge gained from addressing these issues would help predict effects of future changes in forest management on biodiversity and the possible interactions with climate change and dynamic timber markets. The challenge for both managers and researchers concerned with the application of forest management is to improve our understanding of the complex relationships that characterize forest ecosystems and the trade-offs necessary to ensure a sustainable future for British forests and their wildlife.

I am grateful to the organizers of the conference on ‘Woodland birds; their ecology and management’ for the invitation to make the presentation on which this paper is based. Graham Bull and Shona Cameron provided the summary of data from the four post-War censuses of woodlands. I am grateful for comments on early drafts of this paper from David Jardine, Chris Quine and Gary Kerr, and for the helpful suggestions of two anonymous referees.

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  2. Abstract
  3. SOURCES OF INFORMATION
  4. DEVELOPMENT OF THE FOREST RESOURCE SINCE 1945
  5. DEVELOPMENTS IN SILVICULTURE
  6. MARKETS AND MANAGEMENT
  7. FUTURE ISSUES
  8. REFERENCES
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