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Using inventory data to determine the impact of drought on tree mortality

Informally Refereed

Abstract

Drought has been the subject of numerous recent studies that hint at an acceleration of tree mortality due to climate change. In particular, a recent global survey of tree mortality events implicates drought as the cause of quaking aspen mortality in Minnesota, USA in 2007. In this study, data from the Forest Inventory and Analysis program of the USDA Forest Service were analyzed for the period 2000-2009. The fate of individual trees was tracked on a 5-year return interval and the proportion of trees that died was examined in relation to the Palmer Drought Severity Index for the same time period. Quaking aspen mortality increased in northeastern Minnesota over the study period but was stable in north-central Minnesota. The rate of quaking aspen mortality was found to be significantly higher than the mortality rate of all tree species combined in northeastern Minnesota in recent remeasurement periods. Aspen mortality cannot be conclusively attributed to drought without further analysis of contributing factors. While anecdotal observations of small-scale mortality have been cited as evidence of climate-change-induced mortality in other studies, the results of this study suggest further exploration of statistical models for apportionment of inciting, predisposing, and contributing tree mortality factors.

Parent Publication

Citation

Liknes, Greg C.; Woodall, Christopher W.; Perry, Charles H. 2012. Using inventory data to determine the impact of drought on tree mortality. In: McWilliams, Will; Roesch, Francis A. eds. 2012. Monitoring Across Borders: 2010 Joint Meeting of the Forest Inventory and Analysis (FIA) Symposium and the Southern Mensurationists. e-Gen. Tech. Rep. SRS-157. Asheville, NC: U.S. Department of Agriculture, Forest Service, Southern Research Station. 109-112.
https://www.fs.usda.gov/research/treesearch/40980