Tree leaves serve many functions they manufacture food for the tree, shade the area, serve as baffles to harsh noises and other sounds, provide settling surfaces for dust particles, intercept surfaces for rain and snow, and when dead, furnish nutrients and organic matter to the soil. Trees add greatly to the aesthetics of an area, helping to soothe the soul of all mankind. They also furnish food, shelter and a favorable habitat for many kinds of birds, insects, and other animals. In winter, they tend to make the area warmer by reducing wind velocity. They tend to cool the area around them in the summer through shade and transpiration.
Tree roots penetrate to great depths in the soil to obtain nutrients and moisture needed for growth.
In so doing, they create many tiny channels in the soil so that rainfall can percolate down into the earth and recharge the underground water supply. By aiding in this percolation, by binding the soil with their roots, and by the interception of precipitation provided by their leaves, trees aid materially in reducing water run-off and soil erosion. The forest litter formed by fallen leaves and twigs decomposes furnishing food and a home for many important soil organisms including worms, bacteria, and fungi. Eventually this litter returns to the soil in the form of chemical nutrients that will again be available to new plants. By serving as a barrier to winds, trees reduce wind velocities, thus reducing the likelihood of wind erosion to the soil, while enhancing the environment for wild and domestic animals in windswept locations.