Widespread Increase of Tree Mortality Rates in the Western United States

Citations Over TimeTop 1% of 2009 papers

Abstract

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.

Related Papers

• → Managing for late-successional/old-growth characteristics in northern hardwood-conifer forests(2006)221 cited
• → Evaluating tree competition indices as predictors of basal area increment in western Montana forests(2011)189 cited
• → Insights on Forest Structure and Composition from Long-Term Research in the Luquillo Mountains(2017)51 cited
• → The effect of competition on individual tree basal area growth in mature stands of Pinus cooperi Blanco in Durango (Mexico)(2005)99 cited
• → Forest composition and structure during a 27-year period of observation in an untreated secondary lowland rainforest in southwestern Nigeria(1988)4 cited