Assessing climate change effects on long-term forest development: adjusting growth, phenology, and seed production in a gap model

The sensitivity of forest development to climate change is assessed using a gap model. Process descriptions in the gap model of growth, phenology, and seed production were adjusted for climate change effects using a detailed process-based growth model and a regression analysis. Simulation runs over 400 years with the adjusted gap model indicate that climate change scenario IPCC IS92A is likely to cause subtle changes rather than abrupt changes in forest development in The Netherlands. Given the responses in growth, phenology, and seed production of trees, forest development in The Netherlands is not likely to be influenced significantly by climate change over the coming 50 years. The largest responses to model outcomes occur from year 100 onwards and indicate that climate change (1) stimulates the production of early-successional forests more than the production of late-successional forests and (2) accelerates the replacement of early-successional species by late-successional species. Linking of detailed process-based models with forest gap models enables interpretation of climate change effects beyond a change in tree growth only, and is an important tool for investigating effects of climate change on the development of mixed forests.