Research objectives and content
- a doubling of the global atmospheric Cø2 concentration and associated, more local changes in climate predicted from General Circulation Models to occur across Europe over the next 100 years will not be detrimental to European forests. Subsidiary hypotheses to be tested are that: - impacts of elevated CO2 and temperature will be limited by availability of nitrogen in northern temperate and boreal forests and by availability of water in Mediterranean forests, and - a delicate balance between gains of carbon by CO2 assimilation and losses by tree respiration and microbial oxidation of soil organic matter determine carbon sequestration in stands and may be tipped one way or the other by rising CO2 and temperature. The primary focus is on stands of the ecologically and environmentally most important trees and forests across Europe. The methodology is to model the CO2 and water exchanges, carbon sequestration and water use, growth and production of forest stands using mechanistic, bottom-up models that contain explicit representation of the processes that are affected by rising CO2 and temperature. The work is focused on the rationalisation, convergence, parameterisation and validation of the suite of models in current use and their application to predicting the likely impacts at stand scale. Upscaling to landscapes and longer time periods will take account of recent knowledge regarding feedbacks but is more speculative. Parameterisation will utilise previous experimental work and will be reinforced by new integrated experimental programmes of ecophysiological measurements in chambers and forest canopies. Validation will be achieved by comparison of predicted fluxes with measured fluxes in today's climate and by comparison of predicted impacts against measured impacts in mini-ecosystems with elevated CO2 created for this purpose. The main products will be: greatly enhanced understanding of the impacts of rising CO2 and temperature at stand scale, a database of parameters, improved and, most importantly, validated models, new hypotheses relating to feedbacks between soil, vegetation and atmosphere at landscape scale over long time periods, and. a set of predictions of likely impacts at stand scale. There will be cooperation with complementary projects with cross-Partnership, in particular FORCE, EUROFLUX and LTEEF-II.