Phenology and photosynthesis

We are interested in the links between autumn phenology and photosynthesis. In contrast to a recently published study by Zani et al. (2020), we find that increasing photosynthesis does not lead to an earlier leaf-shedding in autumn. While a such a relationship appears at the short (inter-annual) time scale (driven probably by variations in the spring phenology and a constrained leaf longevity), it does not hold when evaluating relationships at the decadal time scale and across space. This challenges the interpretation of Zani et al. about the drivers of autumn phenology. It’s probably not about a C sink saturation (once plants have assimilated enough C, they go to sleep for winter). Rather, long-term trends in climate and CO2 enables plants to extend their growing season, wherebey they overcome the leaf-longevity constraint and a trend towards earlier leaf-out does not lead to a corresponding trend towards earlier leaf-off. The opposite is observed - both for decadal-scale temporal trends and trends across space!

This is research I designed and is being led now by Dr. Laura Marques (postdoc in my group).