Long-term climate and competition explain forest mortality patterns under extreme drought
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- 作者：Derek J. N. Young ; Jens T. Stevens ; J. Mason Earles ; Jeffrey Moore ; Adam Ellis ; Amy L. Jirka and Andrew M. Latimer
- 刊名：Ecology Letters
- 出版年：2017
- 出版时间：January 2017
- 年：2017
- 卷：20
- 期：1
- 页码：78-86
- 全文大小：1205K
- ISSN：1461-0248
文摘
Rising temperatures are amplifying drought-induced stress and mortality in forests globally. It remains uncertain, however, whether tree mortality across drought-stricken landscapes will be concentrated in particular climatic and competitive environments. We investigated the effects of long-term average climate [i.e. 35-year mean annual climatic water deficit (CWD)] and competition (i.e. tree basal area) on tree mortality patterns, using extensive aerial mortality surveys conducted throughout the forests of California during a 4-year statewide extreme drought lasting from 2012 to 2015. During this period, tree mortality increased by an order of magnitude, typically from tens to hundreds of dead trees per km2, rising dramatically during the fourth year of drought. Mortality rates increased independently with average CWD and with basal area, and they increased disproportionately in areas that were both dry and dense. These results can assist forest managers and policy-makers in identifying the most drought-vulnerable forests across broad geographic areas.