Dendroclimatic Analysis Using Thornwaite-Mather-Type Evapotranspiration Models: A Bridge Between Dendroevology and Forest Simulation Models

Abstract

The objective of this study was to document correlations between radial growth of white oak (Quercus alba L.) at 128 sites in the eastern US and variables related to early growing season site water balance, including the ratio of actual to potential evapotranspiration (AE/PE) computed based on the procedure described by Thornthwaite and Mather (1957). White oak radial growth was strongly correlated with all measures of early growing season water balance, but was most consistently and strongly correlated with Palmer Drought Severity Index (PDI) and AE /PE ratio computed using a modified Thornthwaite-Mather model. We propose that dendroecological analyses of tree growth responses to climate based on AE /PE variables could provide empirical data useful for improving climate response algorithms in forest simulation models. This change of standard practice could also improve biological interpretations derived from such dendroecological analyses.