A global overview of drought and heat-induced tree mortality reveals emerging climate change risks for forests
A global overview of drought and heat-induced tree mortality reveals emerging climate change risks for forests
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DOI：
10.1016/j.foreco.2009.09.001
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发表时间：
2010-02-05
影响因子：
3.7
通讯作者：
Cobb, Neil
中科院分区：
文献类型：
--
作者：
Allen, Craig D.;Macalady, Alison K.;Cobb, Neil
温室气体排放已经极大地改变了全球气候，并将在未来继续这样做。与气候变化相关的干旱和热胁迫的频率、持续时间和/或严重程度的增加可能从根本上改变许多地区森林的组成、结构和生物地理。特别令人关切的是，与气候引起的生理压力以及与其他气候介导过程（如虫害暴发和野火）的相互作用有关的树木死亡率可能增加。尽管存在这种风险，但现有的树木死亡率预测是基于缺乏功能上现实的死亡率机制的模型，并且没有尝试跟踪全球气候驱动的树木死亡率的观测结果。在这里，我们提出了最近由于干旱和高温胁迫导致的树木死亡的第一个全球评估。虽然在没有气候变化的情况下会发生偶发性死亡，但本文汇编的研究表明，世界上至少有一些森林生态系统可能已经在对气候变化作出反应，并引起人们的关注，即森林可能越来越容易受到更高的背景树木死亡率的影响，并因未来的变暖和干旱而死亡，即使在通常不被认为缺水的环境中也是如此。这进一步表明生态系统服务面临风险，包括森林碳封存和相关大气反馈的损失。我们的综述还指出了目前阻碍我们预测树木死亡率以应对气候变化能力的关键信息缺口和科学不确定性，并强调了建立全球协调观测系统的必要性。总的来说，我们的综述揭示了全球森林干旱和高温导致树木死亡率增加的可能性。Elsevier B.V.出版
Greenhouse gas emissions have significantly altered global climate, and will continue to do so in the future. Increases in the frequency, duration, and/or severity of drought and heat stress associated with climate change could fundamentally alter the composition, structure, and biogeography of forests in many regions. Of particular concern are potential increases in tree mortality associated with climate-induced physiological stress and interactions with other climate-mediated processes such as insect outbreaks and wildfire. Despite this risk, existing projections of tree mortality are based on models that lack functionally realistic mortality mechanisms, and there has been no attempt to track observations of climate-driven tree mortality globally. Here we present the first global assessment of recent tree mortality attributed to drought and heat stress. Although episodic mortality occurs in the absence of climate change, studies compiled here suggest that at least some of the world's forested ecosystems already may be responding to climate change and raise concern that forests may become increasingly vulnerable to higher background tree mortality rates and die-off in response to future warming and drought, even in environments that are not normally considered water-limited. This further suggests risks to ecosystem services, including the loss of sequestered forest carbon and associated atmospheric feedbacks. Our review also identifies key information gaps and scientific uncertainties that currently hinder our ability to predict tree mortality in response to climate change and emphasizes the need for a globally coordinated observation system. Overall, our review reveals the potential for amplified tree mortality due to drought and heat in forests worldwide. Published by Elsevier B.V.