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

气候、干扰和施氮肥对加拿大西部森林碳平衡的影响

• 批准号: 6123-2007
• 负责人: Black, Andrew
• 金额: $ 3.28万
• 依托单位: University of British Columbia
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2007
• 资助国家: 加拿大
• 起止时间: 2007-01-01 至 2008-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=363583
• 关键词: Effects; climate; disturbance; nitrogen; fertilization

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.   We will measure above-canopy CO2, water vapour and sensible heat fluxes using the eddy covariance (EC) approach. In addition to using conventional methods to partition NEP between P and R, we will use EC and chamber measurements of 13CO2 isotope fluxes with tunable diode laser absorption spectroscopy. Heterotrophic respiration will be measured using a modified trenched-plot root-exclusion technique and used to estimate net primary productivity. Soil N2O emissions will be measured using syringe sampling of static chambers. Temporal effects of MPB attack will be inferred from annual NEP measurements in two lodgepole pine stands at early and late stages of attack.   This research will improve our understanding of the role of forests in the global climate system and C balance. Quantification of the effects of fertilization and MPB attack will help develop a strategy for Canada to increase C sequestration in its forests. This work will provide valuable data to validate C cycling models and sound training of two M.Sc. and three Ph.D. students, three postdoctoral fellows and four technicians.

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。 我们将使用涡度相关（EC）方法测量冠层上方的CO2，水蒸气和感热通量。除了使用传统的方法来分区P和R之间的NEP，我们将使用EC和腔室测量13 CO2同位素通量与可调谐二极管激光吸收光谱。异养呼吸将采用改良的沟地根排除技术进行测量，并用于估计净初级生产力。土壤N2 O排放量将使用静态室的注射器采样进行测量。MPB攻击的时间效应将推断从每年的NEP测量在两个火炬松站在早期和后期的攻击阶段。 这项研究将提高我们对森林在全球气候系统和碳平衡中的作用的认识。施肥和MPB攻击的影响的量化将有助于制定加拿大的战略，以增加其森林中的碳固存。这项工作将为验证C循环模型和两名硕士和三名博士的良好培训提供有价值的数据。学生，三名博士后研究员和四名技术人员。