Phenology across scales: An intercontinental analysis of leaf-out dates in temperate decidous tree communities

Authors: DELPIERRE, NICHOLAS - National Council For Scientific Research-Cnrs; GARNIER, SUZON - National Council For Scientific Research-Cnrs; TREUIL-DUSSOUET, HUGO - National Council For Scientific Research-Cnrs; HUFKENS, KOEN - University Of Bern; BERVEILLER, DANIEL - National Council For Scientific Research-Cnrs; LIN, JIANHONG - National Council For Scientific Research-Cnrs; MORFIN, ALEXANDRE - National Council For Scientific Research-Cnrs; WILKINSON, MATTHEW - Forest Research; NOORMETS, ASKO - Texas A&M University; KLOSTERHALFEN, ANNE - Hochschule Geisenheim University; DOMEC, JEAN-CHRISTOPHE - Biophytis; CUNTZ, MATTHIAS - Université De Lorraine; JOETZJER, EMILIE - Université De Lorraine; MUNGER, J. WILLIAM - Harvard University; RICHARDSON, ANDREW - Northern Arizona University; HART, KRIS - University Of Birmingham; Denham, Sander; DESAI, ANKUR - University Of Wisconsin; SOUDANI, KAMEL - National Council For Scientific Research-Cnrs

Submitted to: Global Ecology and Biogeography
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/13/2024
Publication Date: 10/1/2024
Citation: Delpierre, N., Garnier, S., Treuil-Dussouet, H., Hufkens, K., Berveiller, D., Lin, J., Morfin, A., Wilkinson, M., Noormets, A., Klosterhalfen, A., Domec, J., Cuntz, M., Joetzjer, E., Munger, J., Richardson, A.D., Hart, K.M., Denham, S.O., Desai, A.R., Soudani, K. 2024. Phenology across scales: An intercontinental analysis of budburst in temperate deciduous tree communities. Global Ecology and Biogeography. 33(12). Article e13910. https://doi.org/10.1111/geb.13910.
DOI: https://doi.org/10.1111/geb.13910

Interpretive Summary: Main conclusions. We conducted the first intercontinental (EUR / USA) analysis of the variability of budburst at the scale of tree communities. North American and European forests show similar ICV of budburst, in spite of their differences in terms of species richness and weather trends, highlighting the strong environmental control on ICV. We quantified two ecological implications of ICV (difference in terms of radiation absorption and exposure to late frost), that should be explored in a context of changing climate which affects individual trees differently according to their phenological niche.

Technical Abstract: Aim. To quantify the intra-community variability of budburst in temperate deciduous forests, assess its link with species diversity, identify its environmental drivers, and assess its ecological consequences. Location. USA (9 sites) and Europe (EUR, 8 sites). Time period. 2009-2022 Major taxa studied. Temperate deciduous forest trees of the North American and European floras. Median number of dominant tree species in each forest was 5 in the USA, and 2 in EUR. Methods. We developed an approach to quantify the intra-community variability of budburst (ICV) through the analysis of RGB images taken from phenological cameras (phenocam). We related ICV to the species richness and environmental conditions. We quantified the intra-community variability of radiation absorption and exposure to late frost. Results. Budburst occurred over a longer time interval in the USA than in EUR forests. The distributions of ICV were not different in EUR and in USA forests, despite the latter being more species-rich. In both the USA and EUR, cooler conditions during budburst and an earlier occurrence of budburst resulted in higher ICV. In both continents, ICV resulted in a ca. 10% difference of radiation absorption among individual trees over the growing season. Forest communities in the USA had shorter safety margins as regards the exposure to late frosts, and were actually more frequently exposed to late frosts in our dataset.