ИСТИНА

The possible changes of Net Ecosystem Exchange (NEE) of CO2, Gross Primary Production (GPP) and evapotranspiration (E) of tropical rain and temperate spruce forests due to projected future climate change are estimated using a process-based model, climate and vegetation change scenarios. For modeling experiments two representative forest ecosystems were selected: the tropical rain forest situated in Indonesia close to equator, and temperate spruce forest situated in European Russia at the southern boundary of the boreal forest zone. For model projections several scenarios assuming future changes of climate conditions, species composition, plant biomass and nutrient supply were applied. Available climate change scenarios for the 21st century assume a double increase of CO2 concentration in the atmosphere, an increase of the air temperature and precipitation and, at the same time, a decrease of incoming solar radiation and water vapor deficit. Scenarios of vegetation change assume possible increase due to global warming of the fraction of deciduous trees species in the boreal forest community and corresponding reduction of spruce tree proportion. Results of modeling experiments show that under sufficient nutrient supply the climate changes can lead to increase of GPP and NEE, and as well as to small E decrease. Reduction of nutrient supply can result in decrease of GPP and E. In particular the decrease of nutrient supply of about 20% can completely offset the possible GPP increase due to projected increases of temperature and CO2 concentration in the air.