Directional responses of trees in the eastern U.S.

Abstract

Climate change can result in shifts in species distribution ranges. However, the interactions between rising temperatures, shifting in precipitation patterns, and forest disturbances make understanding species distribution shifts a challenge, raising the need for an abundance-based, omnidirectional approach, because shifts might not be simply to higher latitudes and elevations. In this study, Forest Inventory and Analysis (FIA) data was used to examine the species range shift of 98 tree species, based on number of stems and basal area during the last 30 years. It was tested if the shifts were life stage sensitive (sapling vs. trees) and trait specific. The data suggested that the majority (70%) of species have shifted abundances westward. Saplings were found to have shifted more than adult trees, as indicated both in total number of species (75 sapling species vs. 57-69 adult tree species shifting west) and median distance shifted (87 vs. 56 km, respectively). Further, it was found that species with significant westward shift have significantly higher maximum precipitation tolerance and wood density than other species. These findings suggest that precipitation plays a significant role in species range shift. Managers and policy makers should consider the omnidirectionality of abundance changes and the interaction between climate change and current forest disturbances when creating mitigation plans for tree species