Belowground biomass dynamic in eastern Canadian forest ecosystems

加拿大东部森林生态系统的地下生物量动态

• 批准号: 238508-2011
• 负责人: Krasowski, Marek
• 金额: $ 1.89万
• 依托单位: University of New Brunswick
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2011
• 资助国家: 加拿大
• 起止时间: 2011-01-01 至 2012-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=478879
• 关键词: Belowground; biomass; dynamic; eastern; Canadian

I am studying long-time fluctuations in biomass of roots of eastern Canadian forests dominated by balsam fir or sugar maple. Their coarse roots represent a large, long-lasting portion of their biomass. The fine, absorbing roots, on the other hand, constitute a continually turning over biomass. The fine roots do not last long and must be replenished. Growth of coarse roots and, particularly, the replacement of dying fine roots cost trees much of their fixed carbon (C). These investments reflect on the amount of free CO2 in the atmosphere, as does the release of C from respiration and decay of dead roots. By estimating variation in production and mortality of the roots, my studies provide an important input to modeling C cycling of Earth's ecosystems. Such models predict changes in atmospheric CO2 concentrations and the resultant change of climate. I excavate coarse roots to determine their biomass but I look for other tree characteristics whose measurement can predict coarse root biomass with acceptable accuracy. I study fine roots by observing them with a camera through transparent tubes (minirhizotrons) placed in the soil. Based on the time of appearance, disappearance, and size of the roots, I estimate changes in fine root biomass over time. I use this approach to study differences in fine root dynamics between the studied species and to determine effects of tree aging on belowground productivity and biomass. I will also use it to study effects of thinning and logging on belowground biomass. These treatments radically change conditions at forest sites and leave large amounts of dead biomass in roots and stumps. However, they also increase productivity of residual trees and, from renewal of vegetation at harvested sites, create conditions for renewed productivity. My studies will provide data useful for planning forest operations to maximize the removal of CO2 from the atmosphere and to reduce its release from forest ecosystems. Hence, my studies may add to options for reducing concentrations of atmospheric CO2 by choosing effective methods of forest management.

我正在研究加拿大东部以香脂冷杉或糖枫为主的森林的根部生物量的长期波动。它们的粗根在其生物量中占很大的，持久的部分。另一方面，细小的吸收性根系构成了不断周转的生物量。细根不能持久，必须补充。粗根的生长，特别是垂死细根的替代，消耗了树木大量的固定碳（C）。这些投资反映了大气中游离CO2的数量，以及呼吸和死根腐烂释放的C。通过估计根的产量和死亡率的变化，我的研究提供了一个重要的输入模拟地球生态系统的碳循环。这种模式预测大气中二氧化碳浓度的变化以及由此产生的气候变化。我挖掘粗根，以确定其生物量，但我寻找其他树木的特点，其测量可以预测粗根生物量与可接受的精度。我通过放置在土壤中的透明管（微型电子管）用相机观察细根来研究它们。根据出现的时间，消失，和大小的根，我估计随着时间的推移细根生物量的变化。我用这种方法来研究所研究的物种之间的细根动态的差异，并确定树木老化对地下生产力和生物量的影响。我还将用它来研究间伐和伐木对地下生物量的影响。这些处理从根本上改变了森林的条件，并在根部和树桩中留下大量死亡的生物量。然而，它们也增加了剩余树木的生产力，并通过恢复采伐地点的植被，为恢复生产力创造了条件。我的研究将提供有用的数据，规划森林业务，以最大限度地消除二氧化碳从大气中，并减少其从森林生态系统的释放。因此，我的研究可能会增加通过选择有效的森林管理方法来降低大气CO2浓度的选择。