The Hidden Clock

Some trees can count. They track light, temperature, and moisture patterns over years to predict when to bloom or seed. It’s nature’s built-in calendar.

How does your internal clock sync with nature’s?

Sources

• USA National Phenology Network — the long-running record of how plants time bud burst, bloom, and seed
• Chilling temperature and photoperiod influence the timing of bud burst in juvenile Betula pubescens and Populus tremula trees — Annals of Forest Science 2015, on the accumulated-cold-then-accumulated-warmth mechanism behind the “counting”

Sources checked 2026-08-12.