Assessing the Impact of Climate

Rapid climate change can have a significant impact on the distribution and biology of trees. As aproactive adaptation measure, cities can stock their urban forests with tree species that will perform wellin predicted future climates.

This article presents a method for assessing the suitability of urban tree

species for predicted future climates through a case study in Philadelphia. Changes of the optimal

distribution ranges of major tree species planted in Philadelphia were evaluated by comparing the

climate envelopes of those species with the predicted climate in the midcentury. Influences of climate

change on major tree disease and pests in Philadelphia were also assessed by inspecting the potential

effects of climate change on the biology of pathogens and pests. The results indicate that the future

climate in Philadelphia will become less optimal for 10 tree species, while two species will thrive. Major

pests and diseases in Philadelphia will generally become more problematic but occurrences of several

diseases and pests may decline. It was suggested that the optimal distribution ranges of trees and their

maintenance needs must be considered at the same time when selecting tree species for urban greening

projects. Overall, the predicted climate change in Philadelphia will likely increase the choices of tree

species for the city.