Fusing tree-ring and forest inventory data to infer influences on tree growth
AuthorEvans, Margaret E. K.
Falk, Donald A.
Swetnam, Tyson L.
Holsinger, Kent E.
AffiliationUniv Arizona, Tree Ring Res Lab
Univ Arizona, Dept Ecol & Evolutionary Biol
Univ Arizona, Sch Nat Resources & Environm
Univ Arizona, Inst BIO5
hierarchical Bayesian model
MetadataShow full item record
CitationFusing tree-ring and forest inventory data to infer influences on tree growth 2017, 8 (7):e01889 Ecosphere
Rights© 2017 Evans et al. This is an open access article under the terms of the Creative Commons Attribution License.
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AbstractBetter understanding and prediction of tree growth is important because of the many ecosystem services provided by forests and the uncertainty surrounding how forests will respond to anthropogenic climate change. With the ultimate goal of improving models of forest dynamics, here we construct a statistical model that combines complementary data sources, tree-ring and forest inventory data. A Bayesian hierarchical model was used to gain inference on the effects of many factors on tree growth-individual tree size, climate, biophysical conditions, stand-level competitive environment, tree-level canopy status, and forest management treatments-using both diameter at breast height (dbh) and tree-ring data. The model consists of two multiple regression models, one each for the two data sources, linked via a constant of proportionality between coefficients that are found in parallel in the two regressions. This model was applied to a data set of similar to 130 increment cores and similar to 500 repeat measurements of dbh at a single site in the Jemez Mountains of north-central New Mexico, USA. The tree-ring data serve as the only source of information on how annual growth responds to climate variation, whereas both data types inform non-climatic effects on growth. Inferences from the model included positive effects on growth of seasonal precipitation, wetness index, and height ratio, and negative effects of dbh, seasonal temperature, southerly aspect and radiation, and plot basal area. Climatic effects inferred by the model were confirmed by a den-droclimatic analysis. Combining the two data sources substantially reduced uncertainty about non-climate fixed effects on radial increments. This demonstrates that forest inventory data measured on many trees, combined with tree-ring data developed for a small number of trees, can be used to quantify and parse multiple influences on absolute tree growth. We highlight the kinds of research questions that can be addressed by combining the high-resolution information on climate effects contained in tree rings with the rich tree-and stand-level information found in forest inventories, including projection of tree growth under future climate scenarios, carbon accounting, and investigation of management actions aimed at increasing forest resilience.
NoteOpen Access Journal.
VersionFinal published version
SponsorsCollege of Science, University of Arizona; USDA-AFRI Grant [2016-67003-24944]; EU Horizon Project "BACI" ; Swiss National Science Foundation [P300P2_154543]