Continuous cover silviculture

Summary

Continuous cover at Kyloe Woods, Northumberland Continuous cover silviculture is based upon a presumption against clearfelling, the use of natural regeneration and the creation of a varied forest structure containing a range of species (Mason, et al., 1999; Mason and Kerr, 2004). Transformation is the process of increasing within-stand structural diversity in even-aged forests and in many cases will lead to conditions favouring continuous cover.

Continuous cover silviculture has recently become important due to a number of factors, such as the Rio-Helsinki process, the requirements of certification and an international movement favouring more natural forest management. All these factors began to change thinking about appropriate silvicultural systems for forests in Britain.

This has resulted in a move away from the predominant silvicultural practice where even-aged stands of a few species are managed using the clearcutting system (Matthews, 1989) and the clearfelled areas are often 5-20 hectares or more in size.

Continuous cover is an approach to forest management that seeks to create more diverse forests, both structurally and in terms of species composition. The development of more diverse forests is a sensible way to reduce the risks posed by future changes in the climate and biotic threats (Stokes and Kerr, 2009).

The challenge is to provide a scientific basis and the associated technology transfer to help silviculture meet the demands of the rapid policy developments that have occurred over the past decade.

The aims of this research programme are thus to:

Carry out research to increase understanding and improve practice of transformation and continuous cover silviculture in British forests
Communicate with forest managers, policy makers and scientists
Ensure a balance of research and technology transfer that supports the requirements of the country strategies in England, Scotland and Wales
Work with partners in the UK and abroad.

Research objectives

Continuous cover with Beech at Ebworth Estate The medium term objectives are:

To define the best methods of transforming even-aged stands to more diverse structures and how these should vary for different species and site types.
To understand the best methods for developing mixed species stands and how these should vary for different regions and site types.
To understand the operational requirements of diversifying British forests.
Determine the key factors influencing the success of underplanting and investigate how will they be affected by climate change.

Further information can be found on the respective projects pages.

Funders and partners

Forestry Commission logo
This research is funded by the Forestry Commission Continuous cover silviculture programme (Alternative Management Approaches).

Scottish Forestry Trust logo EU flag
Other funders include the Scottish Forestry Trust and REINFFORCE (An INTERREG project of the EU).

The project works in close partnership with Forestry Commission Scotland at the Glentress CCF Trial Area and Forestry Commission Wales at Clocaenog CCF Research Area. Two members of the team also sit on the Forestry Commission CCF Working Group.

Forestry Commission policy

Simple structure of Douglas fir at Longleat Continuous cover silviculture is now being widely practised in British forests and it has recentyl been estimated that greater than 10% of all Forestry Commission woodlands use it. There is no doubt that this percentage will increase because of policy developments. For example in Wales diversifying approaches to management is a key strategic objective in Woodlands for Wales (Forestry Commission Wales, 2009) that seeks to ‘avoid clearfelling on our own woodland estate whenever alternative management methods would deliver a wider range of ecosystem services’. In addition, the United Kingdom Woodland Assurance Scheme 2006 (UKWAS) requires forest managers to ‘increasingly favour’ CCF in windfirm conifer plantations and semi-natural woodland.

The Forestry Commission’s Science and Innovation strategy for British forestry (Forestry Commission, 2010) has recognised the changes outlined above and made diversifying approaches to forest management one of seven research themes.

Projects

Work in the programme is divided into a number of projects and studies:

Stand manipulation
How to mange stands to achieve continuous cover
Regeneration: establishment and recruitment
Understanding the factors involved in regeneration
Modelling mixed-age and mixed species stands
Developing flexible models of individual tree and stand growth for use in British forestry
Operational aspects
Practical implementation of silvicultural prescriptions
Risks of windthrow
Improving existing models for application to continuous cover - a joint project with the Tree stability and climate change programme
Knowledge transfer
Useful information and links.

A note on terminology

What is a silvicultural system?

The use of alternative silvicultural systems, such as shelterwood and selection, generally involve retaining some mature trees on the site during the regeneration phase. This approach is also known in Britain as Continuous Cover Forestry (CCF) which is defined in the UK Forestry Standard as the use of ‘silvicultural systems whereby the canopy is maintained at one or more level without clear-felling’.

The UK Woodland Assurance Standard audit protocol refers to ‘lower impact silvicultural systems’. These are synonymous, to all intents and purposes, with CCF.

Status

This work is a key part of the Forestry Commission programme on Alternative Management Approaches.

This programme commenced in April 2011 and progress will be reviewed annually over a four year period.

Contacts

Gary Kerr
Centre for Forest Resources and Management
Forest Research
Alice Holt Lodge
Farnham
Surrey GU10 4LH

Tel: 01420 22255
Fax: 01420 23653
Email: gary.kerr@forestry.gsi.gov.uk

The following people also work on the programme:

Bill Mason, Project Manager
Sophie Hale, Research Scientist
Duncan Ireland, Technical Development
Victoria Stokes, Research Scientist.

Team members work closely with colleagues in the Technical Services and other parts of Forest Research.

References

Forestry Commission (2010). The Forestry Commission Science and innovation strategy for British forestry ^(PDF-308K). Forestry Commission, Edinburgh.

Forestry Commission Wales (2009). Woodlands for Wales: the Welsh Assembly Government's Strategy for Woodlands. Forestry Commission, Aberystwyth.

Mason, B. and Kerr, G. (2004). Transforming even-aged conifer stands to continuous cover management ^(PDF-88K). Forestry Commission Information Note 40 (Revised). Forestry Commission, Edinburgh.

Mason, B., Kerr, G. and Simpson, J. (1999). What is continuous cover forestry? ^(PDF-81K). Forestry Commission Information Note 29. Forestry Commission, Edinburgh.

Matthews, J.D. (1989). Silvicultural systems. Clarendon Press, Oxford.

Stokes, V. and Kerr, G. (2009). The evidence supporting the use of CCF in adapting Scotland’s forests to the risks of climate change ^(PDF-891K). Report to the Forestry Commission Scotland by Forest Research. Alice Holt Lodge, Farnham, Surrey, England.