Soils without much pore space are dense. They have very little room for soil oxygen, absorb less water, and are more difficult for burrowing animals and roots to get through. Plants do not grow as well in compacted soil. Living Organisms Soils contain a variety of living organisms including bacteria, fungi, roots, and soil animals such as mites, earthworms, snails, and insects. As roots grow through the soil, they break up the soil mass.
Roots contribute organic matter to the soil when they die.
As the roots decay, the tunnels where the roots once grew allow water to move through the soil more easily. Some soil animals feed on organic matter and others feed on living organisms in the soil. Animal burrows allow air into the soil. The feces and remains of soil organisms contribute additional organic matter to the soil. The trees are the most obvious part of the forest.