Simulation of Direct Effects of CO2 and Temperature Increase on Forest Growth: The Lteef Project

Abstract

In the first phase of the EU-funded project on “Long-Term Effects of CO2 and Climate Change on European Forests (LTEEF)”, which ran from 1994–1997, a range of models has been used to analyse long-term effects of climate change on existing forest ecosystems in Europe. This was done by applying the models at a set of generic forest types, in combination with climate scenarios generated in accordance with recent GCM output. In the scenario analysis, special attention was paid to acclimation of forest ecosystems to changing site conditions, impacts on growth rates, and impacts on phenology and timing of vegetation-atmosphere exchange of water and carbon dioxide. Results obtained so far show high variation in model output, even when applied using the same input data for site conditions, thereby reflecting the differences in modelling concepts and the resulting differences in sensitivity to changing site conditions. Modelling results show agreement on growth increases as a result of increased CO2 and temperature, but the variation in model output requires additional model evaluation to determine the suitability of the individual models for such scenario analysis. In the second phase of the project (1998–2000) the models will be updated using recent results from experimental work such as carried out within the ECOCRAFT project, and the models will be tested against time series of daily values of carbon and water fluxes such as measured in the EUROFLUX programme using eddy-covariance measurements. Based on this evaluation, selected models will then be used in combination with forest inventory data to analyse regional-scale impacts of climate change on forests, as well as regional feedback’s in terms of carbon sequestration and timing of carbon and water fluxes over Europe.