Impact of tree species interactions on tree water relations under a warmer and drier climate

Models predict a continuous rise in temperature and more extreme precipitation over the coming century, resulting in intensified hot drought events. These novel conditions will strongly alter forest water dynamics, with major consequences for the global carbon and water cycles. In response to environmental stress, trees can adjust their functional traits to maintain optimal performance under more restrictive conditions, a process referred to as phenotypic plasticity.

Additionally, their interactions with other individuals can modulate their response to abiotic stress. Indeed, favoring tree species mixtures is often advocated as a “climate-smart” measure to reduce the negative impacts of extreme events on forests. However, the biological and physical mechanisms behind interactions’ effects on tree responses to environmental stress are unclear.

This research aims to gain a mechanistic understanding of the role of tree species interactions on tree plastic physiological responses to heat and drought stress. Using an experimental climate manipulation with tree seedlings, and fieldwork in a mature forest subjected yearly to hot droughts, the effect of tree species interactions on the plasticity of tree hydraulic functional traits are investigated.

• Collaborations: Alberto Vilagrosa (CEAM); Fernando Valladares (CSIC)