Comparing the Costs and Revenues of Transformation to Continuous Cover Forestry for Sitka Spruce in Great Britain

Owen Davies,Gary Kerr

doi:10.3390/f6072424

Abstract

Recently continuous cover forestry (CCF) has become an accepted approach to forest management in Britain, but uncertainty about its economic consequences may be a barrier to its wider use. A study was carried out to examine the costs and revenues of transforming a stand of Sitka spruce (Picea sitchensis (Bong.) Carr.) to CCF. The main conclusion is that transformation to CCF need not be more costly than clearfelling and replanting if natural regeneration is successful and the aim is to produce a simple canopy structure. The long-term value of transformation to a more complex canopy structure, with three or more strata, is lower and the extra costs need to be justified in terms of management objectives. The main output from the study is an analysis spreadsheet that empowers practitioners and policy makers to investigate the effects of costs, revenues and discount rates on estimates of net present value over 20 years, 100 years and in perpetuity, to suit local conditions. This paper summarises the method and results of the study in a British context, sets these in a wider international context, and considers the merits, applications and possible further developments of the approach.

Highlights

The massive re-afforestation efforts of the twentieth century saw woodland cover in the UnitedKingdom increase from a low of 5% of the total land area to its current level of 13% [1], but the speed and nature of this plantation establishment, often on marginal agricultural land in the uplands, has had a profound effect on silviculture
While it is generally accepted that clearfelling is likely to continue on the most extreme upland sites, a strong impetus for alternative silvicultural approaches where site conditions are allowed is enshrined in the UK Forestry Standard [4], the United Kingdom Government’s approach to sustainable forest management, and in the UK Woodland Assurance Standard [5], approved by the Forest Stewardship Council (FSC) and the Programme for the Endorsement of Forest Certification (PEFC)
Site conditions are assumed to be sufficiently suitable for the growth and management of Sitka spruce that stands may be thinned without undue risk of wind damage, and that there is a reasonable expectation of successful natural regeneration

Summary

Introduction

The massive re-afforestation efforts of the twentieth century saw woodland cover in the UnitedKingdom increase from a low of 5% of the total land area to its current level of 13% [1], but the speed and nature of this plantation establishment, often on marginal agricultural land in the uplands, has had a profound effect on silviculture. The establishment of large even-aged plantations in areas of relatively high windthrow risk, with rotations often shortened to avoid the risk of catastrophic windthrow above a “terminal” stand top height [2], resulted in many upland forests being managed by clearfelling and replanting. While it is generally accepted that clearfelling is likely to continue on the most extreme upland sites, a strong impetus for alternative silvicultural approaches where site conditions are allowed is enshrined in the UK Forestry Standard [4], the United Kingdom Government’s approach to sustainable forest management, and in the UK Woodland Assurance Standard [5], approved by the Forest Stewardship Council (FSC) and the Programme for the Endorsement of Forest Certification (PEFC). The history of British forestry in the twentieth century means that forest managers are often faced with the challenge of transforming even-aged spruce monocultures, originally intended to be clearfelled, to CCF [6]. Two important points made in [6] are that CCF is an approach to forest management and not a silvicultural system, and its use is constrained by wind risk, soil nutrient regime, the suitability of a species on a site, and mammal browsing

Objectives

Methods

Results

Discussion

Conclusion