Why don't plants grow so well under the crown of a deciduous tree?

Plants do not grow so well under the crown of a deciduous tree because the branches of these trees blocks the light coming from the sun.

Explanation:

Sun is the main source of energy for plants in obtaining energy. Plants has the ability to converts solar energy into the chemical energy in the leaves. This chemical energy i. e. glucose is formed when water molecule reacts with carbondioxide gas in the presence of sunlight. Without sun plants are unable to make their own food.