Why do trees to loose their leaves?
Deciduous trees do. During autumn months the days become shorter triggering a bio-chemical chain reaction in trees causing them to pull nutrients from their leaves and back into the trunk to wait out the autumn and winter. The shorter days means that there is not as much time for photosynthesis and so the leaves, where photosynthesis takes places, are no longer as necessary. When spring arrives and days begin to lengthen there is another bio-chemical chain reaction that triggers the regrowth of leaves.
