Role of transitory non-structural carbon reserves in boreal forest stand dynamics

暂时性非结构性碳储量在北方林动态中的作用

• 批准号: 238461-2011
• 负责人: Landhäusser, Simon
• 金额: $ 2.33万
• 依托单位: University of Alberta
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2015
• 资助国家: 加拿大
• 起止时间: 2015-01-01 至 2016-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=570428
• 关键词: Role; transitory; non; structural; carbon

There is growing national and international interest in the underlying mechanisms of tree mortality and forest decline which have recently been associated with changes in the intensity, length and frequency of drought and climate change. Research in tree mortality has mainly focused either directly or indirectly on the processes related to moisture limitations and its impact on water transport. Moisture limitation is thought to be the main driver that cuts off the water supply to the foliage, leading to the desiccation of these tissues and ultimately to the death of trees. However, drought does not fully explain the death of trees and overall forest decline. A possible alternative explanation of this decline is carbon (C) starvation. This hypothesis suggests that due to closed stomata and reduced C assimilation trees could suffer from insufficient and depleted C reserves necessary to maintain their basic respiration needs during high and prolonged stress. This hypothesis has not been rigorously tested and empirical data that support or challenge this hypothesis are scarce. I propose to test the overarching hypothesis that during times of stress when C assimilation is limited, C reserves in tissues will play a critical role in the performance and mortality of seedlings and mature trees. Further, I will investigate various aspects of C reserve allocation to the crown, stem, and root system during and after periods of C limitation in field and controlled growth chamber studies. I will also monitor C limitation effects on processes related to regeneration and mortality. My research program will provide training for HQP in ecophysiology and forest ecology in a collaborative environment. Understanding the role of C reserves in trees could lead to the use of stored C reserves as an early indicator of stress in trees thereby serving as a risk assessment tool for determining forests' health, resiliency, and adaptability to climatic change; thus providing research vital to Canada's forests and its associated economy.

国内外对树木死亡和森林衰退的根本机制越来越感兴趣，这些机制最近与干旱和气候变化的强度、持续时间和频率的变化有关。树木死亡率的研究主要直接或间接地集中于与水分限制相关的过程及其对水输送的影响。 水分限制被认为是切断树叶供水的主要驱动因素，导致这些组织干燥并最终导致树木死亡。然而，干旱并不能完全解释树木的死亡和森林的整体衰退。这种下降的一个可能的替代解释是碳（C）匮乏。这一假设表明，由于气孔关闭和碳同化减少，树木在高压力和长期压力下维持基本呼吸需求所需的碳储备可能会不足和耗尽。该假设尚未经过严格检验，支持或挑战该假设的经验数据也很少。 我建议检验一个总体假设，即在碳同化受到限制的胁迫时期，组织中的碳储备将对幼苗和成熟树木的性能和死亡率发挥关键作用。此外，我将在田间和受控生长室研究中的碳限制期间和之后研究碳储备分配到树冠、茎和根系的各个方面。我还将监测碳限制对再生和死亡率相关过程的影响。 我的研究项目将为 HQP 在协作环境中提供生态生理学和森林生态学方面的培训。 了解碳储量在树木中的作用可能会导致使用储存的碳储量作为树木压力的早期指标，从而作为确定森林健康、恢复力和气候变化适应性的风险评估工具；从而提供对加拿大森林及其相关经济至关重要的研究。