Does drought advance the onset of autumn leaf senescence in temperate deciduous forest trees?

Abstract. Severe droughts are expected to become more frequent and persistent. However, their effect on autumn leaf senescence, a key process for deciduous trees ecosystem functioning, is currently unclear. We hypothesized that (I) severe drought advances the onset of senescence in temperate (II) tree species show different dynamics under drought. tested these hypotheses using manipulative experiment beech saplings 3 years monitoring mature beech, birch oak Belgium. The was derived from seasonal pattern chlorophyll content index loss canopy greenness generalized additive models piecewise linear regressions. Drought associated heat stress increased atmospheric aridity did not affect both trees, even if showed high mortality an advanced greenness. observe major differences among species. To synthesize, timing appears conservative across independent drought, aridity. Therefore, study avoid confusion studies, should be considered separately.