long-term research in uneven-aged silviculture at glentress forest, scotland
DESCRIPTION
This poster by Edward Wilson and Philippe Morgan was first presented at the Society of American Foresters National Convention, Silviculture Matters!, North Charleston, South Carolina, 23-27 October 2013. The poster presents an overview of the Glentress Trial, at Glentress Forest, Scotland. The trial was established by Professor M. L. Anderson in 1952 as a demonstration area for the transformation to an irregular structure of an even-aged, planted forest. The trial area (117 ha) was set out in a large commercial plantation on an exposed, upland site (~300 m); Anderson wanted to determine if uneven-aged silvicultural systems could be adopted in such locations. The dominant species include Sitka spruce, Douglas fir, European larch and Scots pine. The most important silvicultural system that has been applied is group selection, with group sizes varying from 0.1 to 0.2 ha. Groups have been restocked by planting and natural regeneration. Recent surveys of the trial area demonstrate the gradual transformation to an irregular structure after 60 years. The Glentress Trial is recognised as one of the longest-running research sites in British forestry. The trial has been important for both primary research and for developing operational experience in uneven-aged silviculture. Over the decades since its initiation, the objectives of forestry in Britain have evolved and changed. Today the Glentress Trial has a new relevance as we recognise the importance of uneven-aged forests for their ecological resilience and potential to deliver a wide range of ecosystem services.TRANSCRIPT
Site and Silviculture
Inventories of the trial area have been undertaken in1952, 1980, 1990 and 2008 (Wilson et al 1999, Kerr etal 2010). Results demonstrate the gradualtransformation to an irregular structure (Figure 4). Thedominant species include Sitka spruce, Europeanlarch, Scots pine and Douglas fir (Figure 5). The mostimportant silvicultural system that has been applied isgroup selection, with group sizes varying from 0.1 to0.2 ha (Figure 6). Groups have been restocked byplanting and natural regeneration (Figures 7 and 8).
Conclusion
The trial has been important for primary research(e.g., Kerr and Macintosh 2012), and for gainingoperational experience in uneven-aged silviculture.Over the decades since its initiation, the objectives offorestry in Britain have evolved and changed. Todaythe Glentress Trial has a new relevance as werecognise the importance of uneven-aged forests fortheir ecological resilience and potential to deliver arange of ecosystem services (Figure 9).
Acknowledgements
The Glentress Trial area is owned by Forestry Commission Scotland. For many years the trial was managed in agreement with the University of Edinburgh. Research is currently directed and supported in partnership with Forest Research.
Literature Cited
• Anderson, M. L. 1951. Spaced group planting and irregularity of stand structure. Empire Forestry Review 30: 328-341
• Anderson, M.L. 1953. Plea for the adoption of the standing control or check in woodland management. Scottish Forestry 7: 38-47
• Anderson, M. L. 1955. High elevation experimental area – Glentress Forest. Unpublished Report. Glentress Archive. Forest Research, Alice Holt, Surrey
• Anderson, M.L. 1960. Norway spruce-silver fir-beech mixed selection forest. Is it possible to reproduce this in Scotland? Scottish Forestry 14: 87–93
• Kerr, G., and H. Mackintosh. 2012. Long-term survival of saplings during the transformation to continuous cover. Forests 3: 787-798
• Kerr, G., M. Morgan, J. F. Blyth and V. Stokes. 2010. Transformation from even-aged plantations to an irregular forest: the world’s longest running trial area at Glentress, Scotland. Forestry 83: 329-344
• Mackintosh, H., G. Kerr and T. Connolly. 2013. Structural change during transformation in the Glentress Trial – an update. Scottish Forestry 67(3): 14-23
• Wilson, E. R., H. W. McIver and D. C. Malcolm. 1999. Transformation to irregular structure of an upland conifer forest. Forestry Chronicle 75: 407-412
Long-term research in uneven-aged silviculture at Glentress Forest, Scotland
Edward Wilson1 and Philippe Morgan2
Summary
The Glentress Trial was initiated in 1952 to gainexperience in transforming plantations to uneven-aged, irregular structure forests. It continues today asone the longest-running silviculture research trials inBritain.
Background
The Glentress Trial is one of four research forestsestablished in Scotland, in 1952, by Professor Mark L.Anderson, Professor of Forestry at the University ofEdinburgh (Figure 1). At that time, the majority ofwoodlands in Scotland were being managed as even-aged plantations. Prof. Anderson was interested inknowing if it was possible to replicate some of themixed-species, irregular structure woodlands he hadseen in Europe (Anderson 1951, 1955, 1960). Hishypothesis was that these would prove to be moresustainable and resilient in the long term, and thatgreater experience should be gained in a wider rangeof silvicultural systems that might be applied to uplandforest sites in Scotland (Anderson 1953).
The four trial areas were established at Glentress,Faskally, Corrour and Cawdor (Figure 2). Of these, thetrial at Glentress has been managed most consistently,and is currently (after over 60 years) the longestrunning silvicultural trial of its type (Kerr et al 2010).The trial area was set out (with six blocks) in a largecommercial plantation on an exposed, upland site(240-550 m) (Figure 3 and Table 1). It is representativeof many planted forests in southern Scotland.
Figure 6. Groups of between 0.1 and 0.2 ha have been made;approx. 1 (left) and 20 yrs (right) after harvest.
Figure 7. Species composition (%) of seedlings and saplings from the2008 Inventory (Macintosh et al 2013). A significantproportion of the seedlings and saplings are broadleafspecies, adding to the diversity of the forest.
Figure 3. Map of the Glentress Trial area. The trial is laid outwith six blocks, each approximately 20 ha. This wasdesigned to facilitate a 6-yr management cycle.
Silviculture MattersNational ConventionSociety of American ForestersCharleston, South Carolina23-27 October 2013
Author Information
1. Edward WilsonDirector, Silviculture Research InternationalPenrith, Cumbria, England CA11 7AY email: [email protected]
2. Philippe MorganVice-President, Association Futaie IrrégulièrePlas y Wenallt, Llanafan, Aberystwyth, Wales SY23 4AXemail: [email protected]
0
50
100
150
200
250
300
350
0 10 20 30 40 50 60
Ste
ms/h
a
Diameter Class (cm)
1952
1980
1991
Cawdor
CorrourFaskally
Glentress
Block Plots (No.) Area (ha)
A 39 17.8
B 32 20.5
C 38 18.7
D 30 14.2
E 40 20.1
F 31 22.1
Total 210 113.4
Figure 2. Map of Scotlandshowing location of the fourtrial areas established in 1952by Professor M. L. Anderson.
Image: ©
Univ
ers
ity o
f E
din
burg
h
Figure 1. Mark Louden Anderson,MC, MA, DSc, FRSE (1895-1961).
Professor of Forestry (1951-1961),The University of Edinburgh.
Table 1. Number of survey plots in each block at the time ofthe 2008 inventory. Block areas in ha.
Figure 4. Stem frequency distribution by size class (dbh) for Block Aat the Glentress trial area on three dates: 1952, 1980 and1991 (Wilson et al 1999). This demonstrates thetransformation from a regular, even-aged structure to amore-or-less irregular structure over 40 years.
14.1
2.8
5.7
1.9 0.11990
15.5
1.5
4.0
3.90.32008
60.5
0.45.8
12.3
21.0
Saplings % (2008)
57.5
0.87.7
15.8
18.3
Seedlings % (2008)
Figure 5. Change in basal area (m3 ha-1) between 1990 and 2008, by species group (Macintosh et al 2013).
0
100
200
300
400
500
600
700
800
Seedlings Saplings
159
337
750
165
De
nsi
ty (N
/ha)
1990
2008
14.1
2.8
5.7
1.9 0.1
1990
Spruce
Pine
Larch
Other Conifers
Broadleaves
14.1
2.8
5.7
1.9 0.1
1990
Spruce
Pine
Larch
Other Conifers
Broadleaves
Figure 8. Seedlingand sapling densityacross the trialarea, 1990 and2008 (Macintosh etal 2013). Deerbrowse is thoughtto have a majorimpact on currentsapling density.
Figure 9. Glentresstrial area (Block E)in 2012. Note thediversity of speciesand size classes.Also, the mountainbike trail, createdas part of the planfor public use andaccess to theforest.