Forest ecosystems are ecologically crucial, covering 30% of land area and strongly contributing to global carbon (C) sequestration. In forthcoming decades, global change scenarii predict for many regions a temperature increase coupled with a reduction in summer rainfall. Increased probability of drought episodes is thus expected even in areas usually not subjected to prolonged summer drought. Forest management will have to deal not only with such an unfavourable context for tree growth but also with an increasing demand and usage of woody biomass. Even in forests or plantations, which are presently only exposed to moderate soil water deficits, it will be necessary to optimize biomass growth per water loss through transpiration. The ratio between these two traits is known as the whole plant water use efficiency (WUE).
Reduced soil water availability has the potential to, at least, restrict C gain and biomass production and, at worst, to contribute to forest dieback. Tree populations will face environmental changes, which are more rapid than trees generation time, thus reducing their ability to adapt through natural selection. It is therefore essential to better understand the mechanisms of tree acclimation to water deficit and to predict the consequences of such constraint on the forest dynamics, and plantation productivity to better choose forest reproductive material.
This side session of the IUFRO 2017 Anniversary conference in Freiburg will discuss contributions of new advances in
- the understanding of the relationship between WUE and drought responses,
- the processes involved in up-scaling WUE from the leaf to the whole plant level,
- the different methods used to estimate WUE
Contributions improving our understanding of WUE at different levels are welcome, including field observations, experimental evidences, and novel conceptual or mechanistic approaches.
Keynote lectures will introduce themes and will be given by:
- J Marshall (University of Idaho) : WUE at the leaf level
- L Cernusak (James Cook University) : WUE at the whole plant level
- B Medlyn (University of Western Sydney) : WUE at the canopy level
- O Brendel (INRA Nancy-Lorraine) : Genetic diversity of WUE