Question

why trees accure more leaves in summer

Answer 1

During summer optimum temperature and availability of light triggers the plants to synthesize more food by the process of photosynthesis, food prepared is used for growing and storing. If the plants have more leaves more food can be prepared, so in summer plants acquire more leaves to produce more food.

Answer 2

During summer optimum temperature and availability of light allow the plant to perform photosynthesis at more faster rate.If the rate to food synthesis is fast then more can be prepared and If plant have more leaves they can store more food.
So in summer plant accquire more leaves .

Hope it will help