Publication Date:
2009-01-24
Description:
Persistent changes in tree mortality rates can alter forest structure, composition, and ecosystem services such as carbon sequestration. Our analyses of longitudinal data from unmanaged old forests in the western United States showed that background (noncatastrophic) mortality rates have increased rapidly in recent decades, with doubling periods ranging from 17 to 29 years among regions. Increases were also pervasive across elevations, tree sizes, dominant genera, and past fire histories. Forest density and basal area declined slightly, which suggests that increasing mortality was not caused by endogenous increases in competition. Because mortality increased in small trees, the overall increase in mortality rates cannot be attributed solely to aging of large trees. Regional warming and consequent increases in water deficits are likely contributors to the increases in tree mortality rates.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉van Mantgem, Phillip J -- Stephenson, Nathan L -- Byrne, John C -- Daniels, Lori D -- Franklin, Jerry F -- Fule, Peter Z -- Harmon, Mark E -- Larson, Andrew J -- Smith, Jeremy M -- Taylor, Alan H -- Veblen, Thomas T -- New York, N.Y. -- Science. 2009 Jan 23;323(5913):521-4. doi: 10.1126/science.1165000.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉U.S. Geological Survey, Western Ecological Research Center, Three Rivers, CA 93271, USA. pvanmantgem@usgs.gov〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19164752" target="_blank"〉PubMed〈/a〉
Keywords:
Abies/anatomy & histology/growth & development
;
*Climate
;
*Coniferophyta/anatomy & histology/growth & development
;
*Ecosystem
;
Fires
;
Models, Statistical
;
Nonlinear Dynamics
;
Northwestern United States
;
Pinus/anatomy & histology/growth & development
;
Temperature
;
*Trees/growth & development
;
Tsuga/anatomy & histology/growth & development
;
United States
Print ISSN:
0036-8075
Electronic ISSN:
1095-9203
Topics:
Biology
,
Chemistry and Pharmacology
,
Computer Science
,
Medicine
,
Natural Sciences in General
,
Physics
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