Why do trees lose their leaves?

There are two main types of trees, evergreens which maintain their foliage throughout all of the year and deciduous trees which shed their leaves every winter. During autumn the leaves of deciduous trees will start to change color and gradually fall off onto the ground below.

This process of this leaf loss is done to conserve the trees energy and prevent damage over the upcoming winter. Because of the large surface area of the trees leaves the cold and dry winds over the winter months would strip all the moisture from the tree. Therefore by losing its leaves the tree can conserve all its moisture in the trunk and branches. The lack of leaves also means that the tree needs less energy to stay alive and healthy.

As the days get shorter and the nights start to get longer, trees will make arrangements to lose their leaves by releasing a chemical which ultimately causes the leaf to die and fall off its branch. When the leaves fall onto the ground below it causes a layer of protective mulch that not only insulates its roots but also gives it nutrients to feed off.