There are some other life forms in forest community as wall. Birds sing from treetop, frogs peep on the ground , and grouse drum on fallen longs. Some creatures can be seen but not heard : a snake slithers for cover, caterpillars devour a leaf, and spiders wait on webs that glisten in the sunshine. Plants and animals compete for living space, both above and below the surface of the ground. It is the joint activity of all living things of the forest as they live , grow, reproduce, and die-that makes for soil improvement.