Optimal forest management for carbon sequestration and biodiversity maintenance : a thesis presented in fulfilment of the requirements for the degree of Doctor of Philosophy in Economics at Massey University, Turitea, New Zealand

Abstract

Managing planted forests for carbon sequestration and biodiversity maintenance has become increasingly important in times of rapid climate change and the loss of biodiversity worldwide. The objectives of this study are to find out private and socially optimal management strategies for planted forests, and suggest an appropriate policy for promoting multiple-use forests. The research attempts: (1) to identify the harvesting strategies of forest stands that can maximise the benefits from timber production and carbon sequestration; (2) to identify the patterns that can balance economic gain and biodiversity maintenance; (3) to examine the actual management strategies and biodiversity conservation attitudes of forest owners; and (4) to recommend policy tools that can be used to align private with socially optimal decisions. The Faustmann model is extended to include carbon sequestration, biodiversity conservation, multiple forest stands and spatial arrangements among forest stands. The Safe Minimum Standard Approach is employed to model biodiversity conservation. The number of birds is used as a biodiversity indicator. A direct search algorithm is used to determine optimal sets of harvesting strategies. The models are applied to planted forests in Yen Bai province, Vietnam. To get primary data, 291 household forest owners and 4 state enterprises, growing Eucalyptus urophylla and Acacia mangium were surveyed. The results show that the actual cutting ages are 5 and 7 years for household and enterprise forests, respectively. Both the optimal timber and carbon rotation ages are between 9 and 11 years for two species. The value of carbon uptake makes the optimal rotation age slightly shorter. The incorporation of spatial arrangements has little impact on the optimal rotation age, but significantly increases the net present value. The inclusion of biodiversity conservation lengthens the rotation age and significantly reduces the profitability of forest owners. Policy implications are that payment for carbon sequestration services of planted forests in Vietnam is feasible. Merging small forest stands of several forest households should be encouraged. Direct payments are an appropriate policy tool to encourage household forest owners to lengthen rotation ages in order to enhance biodiversity.