Forest Soils

Forest soils, where soil formation has been influenced by forest vegetation, are generally characterized by deeply rooted trees, significant ‘litter layers’ or O horizons, recycling of organic matter and nutrients, including wood, and wide varieties of soil-dwelling organisms. There are also soils now covered with forest vegetation, often plantations, on lands that were not naturally forested. These soils are probably undergoing processes that give them ‘forest soil-like’ characteristics, e.g., litter layers from trees, woody organic residues from deep roots, and associated soil microbe and fauna populations. Like other soils, forest soils have developed, and are developing, from geological parent materials in various topographic positions interacting with climates and organisms. Forest soils may be young, from ‘raw’ talus, recent glacial till or alluvium, or ‘mature,’ in relatively stable landscape positions. Just as forest vegetation of the world varies greatly, so do forest soils, e.g., they are shallow, deep, sandy, clayey, wet, arid, frigid, or warm.

Forest soils have been studied by many generations of soil scientists. Some studies have been focused mainly on ecologic characteristics, for example on surface organic layers in forests in Denmark, which introduced the terms ‘mor’ and ‘mull’; while other investigations have dealt with nutrients, water supplies, soil organisms (especially mycorrhiza-forming fungi), fertilizer additions, and other impacts of forest management.

Because human land uses have often appropriated the ‘best’ soils and landscape positions for agriculture, many forest soils are less than optimum in properties that control fertility and potential vegetation productivity.

Source: Daniel Hillel - Encyclopedia of Soils in the Environment. Volume 2-Elsevier_Academic Press (2004)