Improving estimates of tree mortality probability using potential growth rate

Canadian Journal of Forest Research
By:  and 

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Abstract

Tree growth rate is frequently used to estimate mortality probability. Yet, growth metrics can vary in form, and the justification for using one over another is rarely clear. We tested whether a growth index (GI) that scales the realized diameter growth rate against the potential diameter growth rate (PDGR) would give better estimates of mortality probability than other measures. We also tested whether PDGR, being a function of tree size, might better correlate with the baseline mortality probability than direct measurements of size such as diameter or basal area. Using a long-term dataset from the Sierra Nevada, California, U.S.A., as well as existing species-specific estimates of PDGR, we developed growth–mortality models for four common species. For three of the four species, models that included GI, PDGR, or a combination of GI and PDGR were substantially better than models without them. For the fourth species, the models including GI and PDGR performed roughly as well as a model that included only the diameter growth rate. Our results suggest that using PDGR can improve our ability to estimate tree survival probability. However, in the absence of PDGR estimates, the diameter growth rate was the best empirical predictor of mortality, in contrast to assumptions often made in the literature.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Improving estimates of tree mortality probability using potential growth rate
Series title Canadian Journal of Forest Research
DOI 10.1139/cjfr-2014-0368
Volume 45
Year Published 2015
Language English
Publisher NRC Research Press
Contributing office(s) Western Ecological Research Center
Description 9 p.
First page 920
Last page 928
Country United States
State California
Other Geospatial Sierra Nevada, Sequoia National Park, Yosemite National Park
Online Only (Y/N) N
Additional Online Files (Y/N) N
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