Why mulch?       When applied correctly, mulching becomes a maintenance practice that will limit unnecessary and unwanted stresses to a tree or shrub. As trees become stressed they become vulnerable to many pests and diseases lurking about in the environment, which are looking for a new home. The mulch layer will act as a protective barrier over the soil that will keep the soil moist by limiting evaporation. This barrier will also keep the soil at a more constant temperature, which encourages the growth of many beneficial soil microorganisms. Tree roots require oxygen to carry out necessary gas exchange for growth, which is found in the many pore spaces created between varying sized soil particles. The mulch layer over the root zone will keep soil compaction from occurring and unwanted injury to the trees bark by keeping heavy traffic like mowers from coming too close. Over time this mulch will break down releasing small amounts of nutrients and organic matter back into the soil.