Holm oak fecundity does not acclimate to a drier world.

Climate change might impact tree fecundity by altering the relative influences of meteorological and physiological drivers, and by modifying resource investment in reproduction. Using a 13-yr monitoring of Quercus ilex reproduction in a rainfall exclusion experiment, we analysed the interactive effects of long-term increased aridity and other environmental drivers on the inter-annual variation of fecundity (male flower biomass, number of initiated and mature fruits). Summer-autumn water stress was the main driver of fruit abortion during fruit growth.

Rainfall exclusion and thinning can alter the relationships between forest functioning and drought.

Increasing drought caused by the ongoing climate change, and forest management by thinning that aims at mitigating its impact, may modify the current relationships between forest functions and drought intensity and preclude our ability to forecast future ecosystem responses. We used 15 yr of data from an experimental rainfall exclusion (-27% of rainfall) combined with thinning (-30% stand basal area) to investigate differences in the drought-function relationships for each component of above-ground net primary productivity (ANPP) and stand transpiration in a Mediterranean Quercus ilex stand. Rainfall exclusion reduced stand ANPP by 10%, mainly because of lowered leaf and acorn production, whereas wood production remained unaffected.