Climate change and site: Relevant mechanisms and modeling techniques

Forest growth modeling is moving away from description and toward explanation. The acceptance of global warming and effects related to climate change has reinforced this evolution. In the recent past, there have been several reviews of modeling techniques that have addressed, among other things, model structure and hierarchies within models. We argue that models seeking to adequately address climate change must include a specific suite of site characteristics. These range from primary effects of climate change (temperature, CO₂, and O₃ increase) to secondary effects (increase in soil temperature, microbial activity, and changes in precipitation patterns) and tertiary effects (changes in tree phenology and photosynthesis). This paper (i) compares 12 existing individual tree growth simulators designed to address climate change or related effects, (ii) proposes a set of site-related mechanisms and entities to be included in any modeling framework to address climate change, and (iii) suggests appropriate lines of research to attain the goal of a model driven by climate and able to be initialized with readily available metrics.