The phenology group focuses on the seasonal activity of trees in relation to climatic fluctuations and climate change. Our group investigates how chilling temperatures in winter, day length, spring temperature, shade, nutrients or drought regulate leaf phenology of temperate trees and how late spring frosts are affecting tree growth. We mainly use experiments in controlled conditions where these factors are manipulated. Using water isotopes we also aim to track when water connexion is restored between the buds and the vessels in late winter, possibly marking the end of the dormancy. Temperature inside the buds is recorded at a high-resolution scale with fine probes to assess to what extent it differs from the one obtained from standard weather stations and whether it could be corrected according to wind and solar radiation conditions. Finally we are conducting experiments, employing drone based spectral indices to track phenology in mature forest stands subject to drought stress.