Trees provide shelter from the elements, food and homes for a vast variety of wildlife. The shade cast by their leaves determines the pattern of plant growth below.
The leaves fix Carbon from CO2 (a major greenhouse gas) from the atmosphere through a process known as photosynthesis, which also results in the manufacture of oxygen. Their leaves also have a cooling effect in hot dry weather by the process of transpiration (the input of water vapour into the atmosphere).
Their roots take water and nutrients from the soil and help bind the soil together on slopes.
They provide man with one of the most valuable construction materials - wood.
They decompose to enrich the soil when dead. Rotting leaves provide food for fungi, earthworms, snails, slugs and millions of organisms. Shelter for insects, reptiles, other plants and mammals.