Sustainable forest management is the understanding of site productivity and hereditary factors that affect forest growth and development, as well as factors like climate, soil, topography or lay of the land, and how fungi, plants, and animals interact and help or harm each other. Sustainable forest management also requires knowledge of each species’ unique needs and adaptations, how a forest changes over time, and how it responds when disturbed by fire, insect outbreak, tornado, or timber harvesting. Basing forest management decisions on this knowledge and working with nature results in healthy forests, factors are within partial control of the forest manager and owner, such as protecting and building the soil, favoring selected species of vegetation, and controlling livestock and deer. Soil is the product of millennia of soil-building processes. This life-sustaining substance has been abused, squandered, degraded, and lost during recent history. Though we cannot speed the chemical and physical weathering of rocks and minerals to build new soil, sustainable forest management protects that which we have. Most importantly, forests build soil. When forest soils are trafficked with heavy equipment such as tractors or log skidders or by large animals such as cows or horses, compaction occurs. Regardless of the methods used, the harvest and removal of timber disturbs and compacts soil. Sustainable forestry practices limit soil erosion and compaction.