Phenological responsiveness to climate differs among four species of Quercus in North America

1.The timing of the seasonal activity of organisms is a tractable indicator of climate change. Many studies in North America have investigated the role of temperature on the onset date of phenological transitions in temperate deciduous trees and found that the onset of leafing and flowering in numerous species has occurred earlier in recent years, apparently in response to higher temperatures in winter and spring. 2.Few studies have examined the climatic and biogeographic drivers of phenological responses in water-limited ecosystems or explored inter-specific variation in responses of phenological metrics other than the timing of onset, such as the periodicity or duration of phenological activity. 3.This study used phenological observations of four species of Quercus contributed to the USA National Phenology Network database from 2009-2014 to investigate how responses to climate (temperature and precipitation) and geographic location (latitude, longitude and elevation) varied amon...