The altered leaf phenology could impact animals, like birds or caterpillars, that have synced their own annual rhythms to coincide with leaf timings.
Order or family similarity explained little or no variation in leaf out timing.
We also explored the importance of relatedness across four different phylogenetic scales (species, genus, family and order) to examine the level at which relatedness has the strongest influence on leaf out timing.
However, the influence of climate conditions in regulating leaf out timing was not simple; no single climate variable explained more than 36.4% of the variation in leaf out timing explained by climate.
For example, although mean annual temperature has long been accepted as a prominent driver of the variation in leaf out timing, as observed here in many families, mean annual precipitation was by far the strongest predictor of leaf out timing within the Fagaceae family.
Annual precipitation (Bio12) was a particularly strong determinant of leaf out timing within the Fagaceae family.
Understanding the fundamental patterns in leaf out timing across temperate woody species is necessary to understand the temporal variations in the global carbon cycle within and across years.
Relatedness at the genus and species levels explained between 2% and 3.4% of the variation in leaf out timing across the temperate woody species (Fig. 1a, Table 1).
Overall the interactive effects of the different climate variables explained by far the largest proportion of the variation in leaf out timing across all temperate tree species where more than 75% of climate effect was triggered by climate interactions.
To examine these interactive effects further, we examined the relative importance of climate and phylogeny for explaining the differences in leaf out timing for the species within each family.
