Bud phenology data

This dataset contains phenological observations (stored as numbers from 0-6) of white spruce (3 seed sources), black spruce (1 seed source) and Norway spruce (4 seed sources) buds in spring gathered over 2 years (2016-2017) on trees growing in two plantations that were established in two different blioclimate zones in eastern Canada (the northern temperate forest and the boreal mixedwood forest). For each tree, the terminal bud of all branches belonging to the whorl at breast height were observed weekly. We identified inter- and intraspecies variation in bud break timing and in sensitivity to environmental cues (frost probability, GDD, photoperiod) for each phenological stage. We found that spring frosts and photoperiod control the firsts phenological stages and GDD controls the lasts phenological stages which highlights an important ecological trade-off between the maximizing the growing season length and limit frost damage from too early bud burst.