Phenology is the study of the timing of recurring biological events.

You’ve probably heard the expression “timing is everything” and, indeed, when events such as flowering or insect emergence occur can determine life or death. If a tree bursts its buds too early in the spring, for example, frost may damage or kill the new leaf tissue. If it bursts its buds very late, on the other hand, it may be at a competitive disadvantage compared to other trees that began photosynthesizing and growing earlier in the season.