A process-based forest ecosystem model is described and used to investigate the possible responses of forest ecosystems to increased atmospheric concentrations of CO2 and increased temperatures. The model includes tree and understorey daily photosynthesis, respiration, carbon and nitrogen partitioning, growth and death; litter production and decomposition; competition between vegetation types; and a daily weather generator. It requires no boundary conditions except monthly climate parameters, and can be run for any location in the world. Simulations are presented for North America and Europe, with scenarios of past and future changes in atmospheric CO2 and temperature.
A sensitivity analysis shows the importance of soil decomposition processes in controlling productivity. There is an important interaction between temperature and CO2, with photorespiration and decomposition playing key roles.
Key words: ecosystem model, forest dynamics, global change.
Correspondence: Andrew D. Friend, Institute of Terrestrial Ecology, Edinburgh Research Station, Bush Estate, Penicuik, Midlothian EH26 0QB, UK
Telefax: +131-445-3943
E-mail: a.friend@ite.ac.uk