The Response Of Net Primary Productivity On Climate Change In Forest Ecosystem Of Beijing Mountain Area

Since the Industrial Revolution the CO2 concentration globally has increased from 280μmol·mol-1 to 350μmol·mol-1. the climate change must affect the forest ecosystem greatly.One of performance is forest ecosystem NPP changes. Choosing the main forest types in beijing mountain areas as the research object, deciduous broad-leaved,evergreen broad-leaved forest,deciduous needle-leaf forest are classfied to study their responses of NPP.We examined the model and validated the model outputs using observation data, and predict the potential changes in the productivities of forests based on the future climatic change scenario,in order to provide theoretical base for Beijing's reasonable forest management and adaptation strategy.Main outputs of the paper conclude:1) Mean annual temperature variation showed an increasing trend and annual precipitation variation showed a complexing trend during the study period(1974-2010). validated the model outputs, The simulated results showed good agreement with observations of net primary productivity, All the validations suggested that BIOME-BGC model could be used as a diagnostic tool to investigate the response of beijing mountain areas forest to climatic and CO2 change perfectly.2) The result of the average annual NPP Shows significant interannual variation.Three types forest's NPP all showd significant linear correlation with precipitation, but showed no linear correlation with temperature. The precipitation was the key environmental factor controlling the NPP variations during this period of time.3) Under CO2 concentration change scenarios condition,The NPP responded positively to t he scenarios,the responses of NPP were in order:Robinia pseudoacacia>Larix principis -rupprechtii>Quercus variabilis>Vitex Negundo var.heterophylla>Spiraea>Platycladus o rientalis> Pinus tabulaeformis,range from 3.79% to 54.55%.The deciduous broad-leave d forest and deciduous needle-leaf forest reponsed more positively than evergreen broa d-leaved forest.the NPP change over 50% to Robinia pseudoacacia and Larix principi s-rupprechtii.4) Under climate change scenarios condition, The responses of NPP to the temperature ele vated were in order: Robinia pseudoacacia>Pinus tabulaeformis> Quercus variabilis> P latycladus orientalis>Larix principis-rupprechtii.NPP responded positively to precipitatio n changed.Of precipitation:Quercus variabilis>Robinia pseudoacacia>Larix principis-ru pprechtii>Platycladus orientalis>Spiraea>Vitex Negundo var.heterophylla>Pinus tabulaef ormis.Range from 5.32% to 14.58%, Consistent of precipitation and temperature incre ase: Pinus tabulaeformis>Robinia pseudoacacia>Vitex Negundo var.heterophylla=Platy cladus orientalis>Spiraea>Quercus variabilis>Larix principis-rupprechtii.5) Deciduous broad-leaved and deciduous needle-leaf forest responded positively to CO2 co ncentration and temperature elevated, the rest responded negatively.of CO2 concentrati on and temperature elevated were in order: Larix principis-rupprechtii>Robinia pseudo acacia>Quercus variabilis>Pinus tabulaeformis>Spiraea>Vitex Negundo var.heterophyll a>Platycladus orientalis, range from 4.30% to 46.21%. They were responded positiv ely to CO2 concentration and perception increased, of CO2 concentration and percepti on:Larix principis-rupprechtii>Robinia pseudoacacia> Quercus variabilis>Spiraea>Vi tex Negundo var.heterophylla>Platycladus orientalis> Pinus tabulaeformis, range from 3.68% to 54.73%.