The reduction of rotation as a tool for forest adaptation to future risk of dieback induced by drought event

In this paper, we tackle the reduction of rotation from an economic perspective. In a costbenefit framework, we look at the impact of such a reduction on the forest economic value. We concentrate on a Douglas-fir plantation with rotation of 55 years and we wonder about the relevance to reduce to 40 years. We consider the role of climate change (through an increasing drought risk), the role of site fertility and temporal horizon. We also conduct sensitivity analysis on the discount rate and introduce fertilization overcost needed to sustain productivity in shorter rotation. We compare, from an economic point of view, three different adaptation strategies: absence of adaptation (i.e. sylviculture as usual), immediate adaptation and a delayed one. In our case study, the best option for the forest owner in terms of economic return is the absence of adaptation, after it is to delay the adaptation by one rotation and finally to adopt immediate adaptation. However, we also prove that such a trend should be reversed from a damage threshold. Then, with a loss of volume superior to 28% in case of drought event occurrence, an immediate adaptation allows a better economic return than the absence of adaptation. This result seems to suggest that the reduction of rotation may be an adaptation tool for vulnerable stands.