Integrating non-timber objectives into bio-economic models of the forest sector: a review of recent innovations and current shortcomings

This paper gives an overview of non-timber objective modelling in forest sector models (FSM) research through a systematic literature review followed by an in-depth narrative review. Originally conceived to perform projections of timber supply and wood products markets, FSM have been growingly used for forest and climate policy analysis. For this purpose, they have gradually integrated objectives other than timber production, such as habitat conservation, carbon sequestration and bioenergy production. We identify these non-timber objectives and elicit technical innovations that have enabled their integration into FSM. We also discuss their current limits and the new perspectives they bring for a better economic-environmental assessment of forest policies. Results show that the study of non-timber objectives is a growing topic in FSM research, with bioenergy production and climate change mitigation as the most commonly studied. However, there are discrepancies regarding the respective contributions of different families of models, and not all non-timber objectives have been integrated to the same degree. On the one hand, bioenergy production has been thoroughly integrated through marginal modifications of the market component of models. On the other hand, the modelling of carbon sequestration and habitat protection entails deeper changes, such as the addition of new resources to the models, an increase in the complexity of the objective function and associated constraints, or the use of tools and models outside the FSM.