Spatial variance of spring phenology in temperate deciduous forests is constrained by background climatic conditions

Abstract:Leaf unfolding in temperate forests is driven by spring temperature, but little is known aboutthe spatial variance of that temperature dependency. Here we use in situ leaf unfoldingobservations for eight deciduous tree species to show that the two factors that controlchilling (number of cold days) and heat requirement (growing degree days at leaf unfolding,GDDreq) only explain 30% of the spatial variance of leaf unfolding. Radiation and ariditydifferences among sites together explain 10% of the spatial variance of leaf unfolding date,and 40% of the variation in GDDreq. Radiation intensity is positively correlated with GDDreqand aridity is negatively correlated with GDDreqspatial variance. These results suggest thatleaf unfolding of temperate deciduous trees is adapted to local mean climate, including waterand light availability, through altered sensitivity to spring temperature. Such adaptation ofheat requirement to background climate would imply that models using constant temperatureresponse are inherently inaccurate at local scale.

Publication year:2019

Keywords:Biology, Multidisciplinary sciences

BOF-keylabel:yes

BOF-publication weight:10

CSS-citation score:2

Authors:International

Authors from:Higher Education

Accessibility:Open