Effects of climate, disturbance and nitrogen fertilization on the carbon balance of forests in western canada

北方温带和寒带森林是生物量和土壤碳（C）的巨大储存库，对全球光合作用总量作出重大贡献。重要的是要更好地了解这些碳库对气候变化的响应，研究近年来干扰增加的影响，并制定管理措施，将提高其碳汇强度。这项研究将在北方、亚北方和西海岸温带森林进行。本研究的目的是（1）研究气候变化对净生态系统生产力（NEP）、总生态系统光合作用（P）和生态系统呼吸（R）的影响，（2）量化环境因子、物候和P对R和土壤呼吸（Rs）的影响，（3）在其异养组分和根际组分之间分配Rs，（4）研究氮肥对不同林龄美国西海岸花旗松C平衡和N_2O排放的影响;（5）研究山地松甲虫（MPB）对亚寒带黑松C平衡和水分平衡的影响。

Northern temperate and boreal forests are large reservoirs of biomass and soil carbon (C), and make a major contribution to gross global photosynthesis. It is important to better understand the response of these C pools to climate change, to study the impact of increased disturbance in recent years, and to develop management practices that will enhance their C sink strength. This research will be conducted in boreal, sub-boreal and West Coast temperate forest stands. Our objectives are to (1) study the impact of climatic variability on net ecosystem productivity (NEP), gross ecosystem photosynthesis (P) and ecosystem respiration (R), (2) quantify the effects of environmental factors, phenology and P on R and soil respiration (Rs), (3) partition Rs between its heterotrophic and rhizospheric components, (4) assess the effect of nitrogen fertilization on the C balance and N2O emissions in different-aged West Coast Douglas-fir stands, and (5) determine the impact of mountain pine beetle (MPB) attack on the C and water balances of mature sub-boreal lodgepole pine stands.