Could increased boreal forest ecosystem productivity offset carbon losses from increased disturbances?
Could increased boreal forest ecosystem productivity offset carbon losses from increased disturbances?
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DOI：
10.1098/rstb.2007.2198
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发表时间：
2008-07-12
影响因子：
6.3
通讯作者：
Rampley, Greg
中科院分区：
文献类型：
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作者：
Kurz, Werner A.;Stinson, Graham;Rampley, Greg
为了了解北方森林碳(C)动态如何响应预期的气候变化，我们必须考虑两个重要的过程。首先，预计气候变化将增加火灾和其他自然干扰的发生频率，从而改变森林年龄级结构，并减少景观一级的森林C存量。其次，全球变化可能导致净初级生产量(NPP)的增加。更高的NPP能否抵消因干扰增加而预期的C损失？我们使用加拿大森林部门的碳预算模型来模拟假设的北方森林景观在干扰、生长和分解方面的速率变化，并探索这些变化对景观水平森林C预算的影响。我们发现，需要显著增加净生态系统生产量(NEP)，以平衡因自然干扰率增加而造成的碳损失。此外，净资产净值的增长必须在几十年内持续，并在全国范围内广泛传播。只有当NPP相对于异养呼吸增强时，才能实现NEP的增加。这项研究表明，由于气候变化，北方森林的碳储量可能会下降，因为增强的生长很难抵消预期的干扰增加造成的碳损失。
To understand how boreal forest carbon (C) dynamics might respond to anticipated climatic changes, we must consider two important processes. First, projected climatic changes are expected to increase the frequency of fire and other natural disturbances that would change the forest age-class structure and reduce forest C stocks at the landscape level. Second, global change may result in increased net primary production (NPP). Could higher NPP offset anticipated C losses resulting from increased disturbances? We used the Carbon Budget Model of the Canadian Forest Sector to simulate rate changes in disturbance, growth and decomposition on a hypothetical boreal forest landscape and to explore the impacts of these changes on landscape-level forest C budgets. We found that significant increases in net ecosystem production (NEP) would be required to balance C losses from increased natural disturbance rates. Moreover, increases in NEP would have to be sustained over several decades and be widespread across the landscape. Increased NEP can only be realized when NPP is enhanced relative to heterotrophic respiration. This study indicates that boreal forest C stocks may decline as a result of climate change because it would be difficult for enhanced growth to offset C losses resulting from anticipated increases in disturbances.