Forest biodiversity underpins ecosystem functioning and the provision of multiple ecosystem goods and services that are essential to human well-being. Still, the social value of biodiversity is rarely taken into account in the management of forest resources. Forest biodiversity is a public good and, as such, it complicates the process of internalizing its social value in the decisionmaking process. New forest conservation strategies are needed to correct biodiversity supply and promote an efficient use of forest resources. Here we propose a simulation- optimization framework to tackle this issue and compute the supply level of forest biodiversity under climate change, using forest birds as indicators. We describe preferences for wood and biodiversity using a constant elasticity of substitution utility function, and evaluate forest dynamics under climate change using the process-based growth model 4C. We applied our framework to a temperate forest landscape in Southwestern Germany and computed the Samuelson condition for biodiversity supply in the region under climate change. Our results show that the biodiversity supply, expressed as an increase in the abundance of bird indicator species, ranged between 8 to 12.3%, depending on the climate trajectory and the uncertainty related to biodiversity valuations. More intensive climate change scenarios increased the marginal costs of biodiversity provision and reduced the supply level. Moreover, we show how an optimal allocation of management strategies across the study area could realize the required supply. We conclude that coupled ecological-economic models are a promising tool to internalize the social value of biodiversity into forest management plans and to better inform decision-makers.
