Leaf senescence varies widely across species and sites
Autumn leaf senescence marks the end of the growing season in temperate ecosystems. Its timing influences a number of ecosystem processes, including carbon, water and nutrient cycling. Climate change is altering leaf senescence phenology and, as those changes continue, it will affect individual woody plants, species and ecosystems. In contrast to spring leaf out times, however, leaf senescence times remain relatively understudied. Variation in the phenology of leaf senescence among species and locations is still poorly understood.
Panchen et al. record the leaf senescence phenology of 1360 deciduous species at six temperate botanical gardens in two consecutive years, and find that species tend to undergo leaf senescence in the same order at each garden in both years, but across gardens the senescence order is weakly correlated. Leaf senescence times are only minimally influenced by spring leaf out times, growth habit and phylogenetics, and show weaker patterns than leaf out times. Thus, in contrast to the broader temperature effects that determine leaf out times, leaf senescence times are probably determined by a larger or different suite of local environmental effects. Interspecific differences in leaf senescence responses to climate change could affect growing season length, micro-climate and community composition.
This article appears in the special issue Plants and Climate Change.