continuous cover forestry: an alternative model for the sustainable management of woodlands and...
TRANSCRIPT
Edward Wilson1 and Philippe Morgan2
1 Director, Silviculture Research International and Faculty of Forestry, University of Toronto 2 Director, SelectFor Ltd and President, Pro Silva
Institute of Fisheries Management Specialist Conference
Rheged, Penrith, Cumbria
21-23 April 2015
First presented: 21 04 2015
This version (1.1): 02 05 2015
RESEARCH
I N T E R N A T I O N A L
Forestry and Fisheries – Where Next?
Continuous Cover Forestry:
an alternative model for the sustainable management
of woodlands and watersheds in Britain
Outline of Presentation
• British Forestry – the drive for adaptation, resilience and delivery of ecosystem services
• What is Continuous Cover Forestry?
• Environmental benefits and opportunities
• CCF in practice – an evolving knowledge base
• Conclusions
"All our resolves and decisions are made in a mood or frame of mind which is certain to change."
Proust
Ecosystem Services
• Benefits to society from ecosystems
• Millenium Ecosystem Assessment, United Nations (2005).
1. Supporting services: ecosystem services "that are necessary for the production of all other ecosystem services”
2. Provisioning services: "products obtained from ecosystems“
3. Regulating services: "benefits obtained from the regulation of ecosystem processes“
4. Cultural services: "nonmaterial benefits people obtain from ecosystems through spiritual enrichment, cognitive development, reflection, recreation, and aesthetic experiences"
Forestry is Multi-Functional Thirlmere Forest – Stakeholder Engagement
Criteria and indicators of sustainable forest management
Source: Wilson and Leslie 2009
Independent Panel on Forestry (2012)
• Keywords:
– Climate change (43 mentions)
– Adapt/Adaptation (14 mentions)
– Woodland Culture (19 mentions)
– Resilience/resilient (22 mentions)
“Action taken now to increase the resilience of our woodland resource will help reduce the future costs of dealing with the effects of climate change.” (p. 8)
0
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< 15 15–50 51–100 > 100
Are
a ('
000
ha)
Age Class (years)
1947
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< 15 15–50 51–100 > 100
Age Class (years)
1965
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< 15 15–50 51–100 > 100
Age Class (years)
1982
Area of High Forest by Age Class Groups 1947-2000
0
200
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600
800
1000
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1400
1600
< 15 15–50 51–100 > 100
Age Class (years)
2000
Broadleaves Conifers
Source: Mason 2007
• The area of woodland has increased dramatically from 1947-2000 • The amount and complexity of older woodland is increasing
Forest Cover in Britain
Legend :
Green = Forestry Commission Blue = private ownership
Graphic created by CCFG. Forest cover map: Crown Copyright © 2008 Forest Research. Reproduced with permission.
• Approx 3.1 M ha total woodland area. • 13 % of GB land area
• 18% in Scotland • 10% in England
• One of the most highly deforested countries in Europe
• EU average forest cover approx 35% of land area
Threats to UK Forests
Source: Forestry Commission England 2012
• Low Resilience of Existing Forest Resources
– Low number of productive species
– Monoculture stands are most common
• Climate change
– Summer droughts increasingly likely, especially in South and East
– Extreme rain and flooding events are more likely
– Ecosystem change – especially ground plants
• Pests and diseases
– Native and exotic
Kielder Forest Source: Forestry Commission
~90% of conifer forests are managed on the clear-fell system
Conifer Forest Cover in England SP, CP, SS, DF, L’s = 88%
Conifer Species Today
Scots Pine
Corsican Pine
Sitka Spruce
Douglas Fir
Larch (EL, HL, JL)
Other Conifer
The vast majority of conifers are grown in plantations, managed on the clearfell system. Source: Forestry Commission.
Percentage of Braodleaf Cover in England by Species
Oak
26%
Beech
10%
Sycamore
8%
Ash
16%
Birch
12%
Poplar
2%
Sweet chestnut
2%
Elm
0%
Other Broadleaves
11%
Mixed Broadleaves
13%
Data Source National Inventory of
Woodland -England. Reference
date 1998.
Broadleaf Forest Cover in England Oak + Ash + Beech + Sycamore + Birch = 72%
Woodland types in UK Legacy of past policies and actions
15%
10%
10%65%
Ancient semi-natural
Recent semi-natural
Ancient replanted
Recent plantation
Kirby et al. 1998
What Ecological Site Classification (ESC) suggests in terms of the dominant productive species
Effects of climate change on the identity of the most productive conifer species as predicted by Ecological Site Classification for the UKCIP02 2050s High and Low emission scenarios.
ESC is based on temperature, moisture and soil physical properties It does not consider Dothistroma, or any other pests or diseases.
Risk to woodlands on the Public Forest Estate (PFE)
By the 2080s, a risk of 65% of the PFE being classed as ‘unsuitable’ in the absence of adaptation – or 35% decline in productivity
Source: Forestry Commission 2012
25th July 2012 Which tree species to plant for a
changing environment Source: Forestry Commission 2012
New tree disease and pest outbreaks UK
Climate Change Action Plan for the Public Forest Estate (PFE)
We will adopt the principle of anticipatory adaptation. This offers the highest potential gains for forest resilience, and the benefits they provide.
We will take an approach that is ‘not risk averse’.
Global emissions are currently tracking close to some of the more extreme emissions scenarios that have been published, so it is prudent to consider the 2050 high scenario when planning for the future.
Diversification is the theme!
Succession stages in a natural forest
initial stage intermediate stage
open ground
final stage
Strategies for Enhancing Forest Resilience
Modify thinning regimes Extend “rotations”
Diversify Structures CCF
Species choice - genetics/provenance
Mixed species
Assisted migration of native species
New species introduced
Wider use of “minor” species
Adapted from diagram by Jens Haufe
The Read Report (2009) Combating climate change – a role for UK forests
• Key findings “THE ADAPTATION OF UK FORESTS AND WOODLANDS TO CLIMATE CHANGE” (Chapter 9, p. 164) ...
“The majority of woods are likely to be treated as high forest in different forms. Whereas clearfell systems have predominated in the past, in future continuous cover forestry approaches may become more advantageous, because:
– they are thought to be more windfirm
– maintain a more even carbon storage
– show lower soil carbon losses during harvesting
– maintain higher humidity levels.”
• “However, the evidence that they will deliver these benefits needs strengthening.”
• “The silvicultural system per se is however, less important than the structures that it creates and their resilience and robustness in relation to climate change.”
Key components of Continuous Cover Forestry
• “...the use of silvicultural systems whereby the forest canopy is maintained at one or more levels without clear felling.”
Mason et al. 1999
It has 4 main guiding principles:
1. Managing the forest ecosystem
2. Using natural processes
3. Working within site limitations
4. Diversifying stand structure
Prime movers: ProSilva Europe (1989) and CCFG (1991)
Mark Louden Anderson MC MA DSc FRSE (1895-1961)
Professor of Forestry (1951-1961)
The University of Edinburgh Ima
ge
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Un
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rsity o
f E
din
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Key papers: • 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. 1960. Norway spruce-silver fir-beech mixed selection forest. Is it possible to
reproduce this in Scotland? Scottish Forestry 14: 87–93
Ahead of his time! The iconic forward thinker ...
Are there any precedents?
Block Area (ha) A 16.6 B 19.8 C 21.3 D 15.0 E 19.8 F 21.5
Total 117.0
.
N
500 m
500 m
350 m
240 m
560 m
C
B
F
E
D
Glentress Trial Area Glentress Forest
Peebles, Scotland
Road
A
0
50
100
150
200
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350
0 10 20 30 40 50 60
Ste
ms/h
a
Diameter Class (cm)
1952
1980
1991
Source: Glentress Trial, 1991 Inventory
Monitoring the transformation: Size/Frequency Distribution for Block A in 1952, 1980 and 1991
Towards a balanced irregular structure
CCF - Coming in from the Fringe
• Cyril Hart (1995)
• Demonstrated tradition of alternative silvicultural systems
• Wide range of systems applied and developed using a broad range of species
• Strong influence from Europe
• Update Review: Scott McG Wilson (2013)
*Whinlatter Forest
Thirlmere Forest
*Clocaenog Forest
Glentress Forest*
Wykeham Forest*
Stourhead (Western) Estate
Craigvinean Forest*
Aconbury Woods
*Coed Trallwm
Drumlanrig Forest
Selected
Continuous Cover Forests in Britain
This map identifies a selection of woodlands where CCF is an
important component of management.
Legend : Green = Forestry Commission
Blue = private ownership * = GB CCF Trial Area
Graphic created by CCFG. Forest cover map: Crown Copyright © 2008 Forest Research. Reproduced with permission.
Morangie Forest*
*Achray Forest
*Inshriach Forest
*Cym Berwyn Forest
*Dartmoor Forest
final harvest and
regeneration
young growth stage
H<1.3m
pole stage
DBH>10cm DBH<20cm
small timber stage
DBH>20cm DBH<35cm
medium timber stage
DBH>35cm DBH<50cm DBH>50cm
large timber
stage thinning
thicket stage
H>1.3m DBH<10cm
respacing
fallow stage restocking
final harvest
beat up, tending
In order to transform a planted forest we have to:
develop adequate tree stability [“Frame Trees” – esp. Important in uplands]
promote the best trees as likely source for Natural Regeneration [NR]
get the species composition right [evidence supports more mixed-species]
create optimal conditions for NR [ground vegetation, seedbed, browse control]
Stand development and transformation
Adapted from diagram by Jens Haufe
Modified thinning in Douglas fir: starting the transformation early
is key to future stand stability
Wythop Wood, Cumbria Photo: Gareth Browning
Light demand of conifer seedlings
Species Overstorey BA for
seedling establishment [m2/ha]
Overstorey BA for seedling growth
[m2/ha]
Shade tolerance of seedlings
JL/EL 20-25 15-20 Intolerant SP/LP/CP 25-30 20-25
SS 30-35 25-30 Intermediate DF 35-40 30-35
NS 40-45 35-40
Tolerant WH
leader/lateral shoot ratio > 1
Management of Seedling Establishment and Growth
Note: Light demand for seedling establishment may be considerably lower than for seedling growth.
management of light level is important
(Source: Forestry Commission Operational Guidance OGB 7)
Environmental Benefits of Forests: Continuous Cover Forestry in a sensitive watershed, Thirlmere Reservoir
37 Photo: E.R. Wilson 2010
Thirlmere, Cumbria
Advanced monitoring systems
• AFI – founded 1991 • Developed advanced monitoring protocols • Now over 100 reference forests, with several
in the UK and Ireland • Forest productivity and ecosystem evaluation
Source: Gareth Browning
Monitoring Systems to Support CCF Management
Example from Wythop
Forest, Cumbria with data on sapling distribution.
Potential Environmental Benefits of CCF for Soils and Water Resources (Ireland et al. 2006)
• Reduced risk of reductions in soil fertility on site
• Maintain soil organic matter within forest stands
• Potential to reduce and minimise soil acidification
• Reduced and mitigated soil disturbance (although stand interventions and operations are likely to be more frequent than in Clear-fell system)
• Greater control over risks of soil erosion and compaction
• Reduced risk of soil contamination and pollution
• Enhanced resilience of multi-species and multi-aged stands in response to threats from pests and diseases, and windstorms
Potential Benefits of CCF on Upland Forest Sites (Reynolds 2004)
• Move away from clear-fell likely to have benefits in terms of reduced nitrate leaching and reduced stream acidification
• Partial harvest encourages retention of nitrate capacity within the soil-plant system
• CCF likely to encourage retention of base cations within soil-plant system, and likely to minimise long-term soil and stream water acidification associated with soil base cation depletion
• If CCF results in smaller proportion of mature Sitka spruce forest, this will reduce nitrate leaching on well-drained acid soils
• Mixed species woodland ecosystems with greater potential to retain nitrogen deposited from the atmosphere should be beneficial on acid sensitive sites
Clocaenog Forest, North Wales CCF Research and Operational Trial in Spruce-dominated upland forest
Photo: E. R. Wilson
Continuous Cover Forestry Group Field Meeting September 2013
Corrour Forest, Scotland Part of the trial network established by M. L. Anderson, 1952 Photo: E. R. Wilson
Conclusions
• Silviculture in Britain exists within a complex historical, economic, ecological and cultural context
• We are currently challenged to find new approaches that ensure the resilience and sustainability of our woodland resources
• Transformation of our forests to more diverse and complex structures (i.e., CCF) is a key strategic challenge, presenting foresters with new opportunities to deliver ecosystem services into the future, including high quality water resources
• There are now well-established management systems for CCF, but evidence for the wider benefits/practice of CCF needs strengthening, especially with respect to water catchments and aquatic ecosystems
Forestry Commission Guidance (Selection of Publications)
• FC: OGB 7 - Managing Continuous Cover Forests (site selection/respacing and thinning/FD planning/production forecast/monitoring)
• FC: OGB 9 - Thinning (Silvicultural Guide) (thinning/stability)
• FCIN 29 What is Continuous Cover Forestry?
• B. Mason, G. Kerr, J. Simpson, 1999
• FCIN 40 Transforming Even-aged Conifer Stands to Continuous Cover Management
• B. Mason, G. Kerr, 2004
• FCIN 45 Monitoring the Transformation of Even-aged Stands to Continuous Cover Management
• G. Kerr, B. Mason, R. Boswell, A. Pommerening, 2002
• FCIN 63 Managing Light to Enable Natural Regeneration in British Conifer Forests
• S. Hale, 2004
Selected references (1)
• 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(2): 38-47
• Anderson, M.L. 1960. Norway spruce-silver fir-beech mixed selection forest. Is it possible to reproduce this in Scotland? Scot. For. 14: 87–93.
• Cameron, A.D. 2002. Importance of early selective thinning in the development of long-term stability and improved log quality: a review. Forestry 75(1): 35-36
• Cameron, A.D. 2007. Determining the sustainable normal irregular condition: A provisional study on a transformed, irregular mixed species stand in Scotland. Scand. J. For. Res. 22: 13-21
• Helliwell, R., and E. Wilson. 2012. Continuous cover forestry in Britain: challenges and opportunities. Quarterly Journal of Forestry
• Ireland, D., T. R. Nisbet and S. Broadmeadow. 2006. Environmental best practice for continuous cover forestry. Environment Agency Science Report SC020051/SR. 78 pp.
• Kerr, G. 1999. The use of silvicultural systems to enhance the biological diversity of plantation forests in Britain. Forestry 72:191–205.
• Macdonald, E., B. Gardiner and W. Mason. 2010. The effects of transformation of even-aged stands to continuous cover forestry on conifer log quality and wood properties in the UK. Forestry 83: 1-16
• Malcolm, D.C., Mason, W.L., and Clarke, G.C. 2001. The transformation of conifer forests in Great Britain – regeneration, gap size, and silvicultural systems. For. Ecol. Manage. 151: 7–23
• O’Hara, K. 2014. Multiaged silviculture: managing for complex forest stand structures. OUP, Oxford. 240 pp.
Selected references (2)
• Mason, W.L. 2002. Are irregular stands more windfirm? Forestry 75: 347–356.
• Mason, W.L., G. Kerr and J.M.S. Simpson. 1999. What Is Continuous Cover Forestry? Forestry Commission Information Note 29. Edinburgh: Forestry Commission.
• Mason, W.L. 2003. Continuous Cover Forestry: developing close-to-nature forest management in conifer plantations in upland Britain. Scot. For. 57: 141–149.
• Nicoll, B.C., B.A. Gardiner and A.J. Peace. 2008. Improvements in anchorage provided by the acclimation of forest trees to wind stress. Forestry 81: 389-398.
• Oliver, C.D., and B.C. Larson. 1996. Forest Stand Dynamics. Update edition. Wiley, New York, 520 pp.
• Page, L. M., and A. D. Cameron. 2006. Regeneration dynamics of Sitka spruce in artificially created forest gaps. Forest Ecology and Management 221: 260-266
• Peterken, G. F. 1996. Natural Woodland. Cambridge University Press, Cambridge. 522 pp.
• Reynolds, B. 2004. Continuous cover forestry: possible implications for surface water acidification in the UK uplands. Hydrology and Earct System Sciences Discuss. 8(3): 306-313
• Read, D.J., P.H. Freer-Smith, J.I.L. Morison, N. Hanley, C.C. West and P. Snowdon (eds). 2009. Combating climate change – a role for UK forests. An assessment of the potential of the UK’s trees and woodlands to mitigate and adapt to climate change. The Stationery Office, Edinburgh. 240 pp.
• Wilson, E.R., H. Whitney McIver and D.C. Malcolm. 1999. Transformation to an irregular structure of an upland conifer forest. For. Chron. 75: 407–412
• Wilson, S. McG. 2013. Progress of adoption of alternative silvicultural systems in Britain: an independent review. Technical Report (March 2013). 49 pp.
Further Information
Contact for further information:
• Edward (Ted) Wilson
– Email: [email protected]
– Website: www.silviculture.org.uk
• Phil Morgan
– Email: [email protected]
– Website: www.selectfor.com
Acknowledgements
• We would like to thank the following colleagues for data and slides that appear in this presentation: Gareth Browning, Bill Mason, John Weir, Mark Broadmeadow, Paul Clavey, Jens Haufe, Barnaby Wylder, Rob Grange.
Forestry and Fisheries – Where Next?
Continuous Cover Forestry:
an alternative model for the sustainable management
of woodlands and watersheds in Britain
Edward Wilson1 and Philippe Morgan2
1 Director, Silviculture Research International and Faculty of Forestry, University of Toronto 2 Director, SelectFor Ltd and President, Pro Silva
Institute of Fisheries Management Specialist Conference
Rheged, Penrith, Cumbria
21-23 April 2015
First presented: 21 04 2015
This version (1.1): 02 05 2015
RESEARCH
I N T E R N A T I O N A L