Draft 1 Accounting for Climate Change in a Forest 1 Planning Stochastic Optimization Model

1 Forest Sciences Centre of Catalonia (CEMFOR-CTFC), E25280, Ctra de St. Llorenç de Morunys Km 2, 5 Solsona, Spain. 6 b Departamento de Ingenieria Industrial, Universidad de Chile, Santiago, Chile 7 *Corresponding author: [email protected], telephone: +351 21365 3309 fax:: +351 21 365 33 38 8 9 Abstract: 10 11 An approach is proposed for incorporating into the forest harvesting decision process the variations in 12 timber growth and yield due to climate change uncertainty. A range of possible climate scenarios are 13 transformed by a forest growth and yield model into tree growth scenarios, which in turn are 14 integrated into a multistage stochastic model that determines the timber cut in each future period so as 15 to maximize net present value over the planning horizon. For comparison purposes a deterministic 16 model using a single average climate scenario is also developed. The performance of the deterministic 17 and stochastic formulations are tested in a case study of a medium term forest planning problem for a 18 Eucalyptus forest in Portugal where climate change is expected to severely impact production in the 19 coming years. Experiments conducted using 32 climate scenarios demonstrate the stochastic model’s 20 superior results in terms of present value, particularly in cases of relatively high minimum timber 21 demand. The model should therefore be useful in supporting forest planners’ decisions under climate 22 uncertainty. 23 24