Cataloging Information
Ecological - Second Order
Soils
The quality of a forest site is governed by its physical conditions (temperature, moisture, soil parent materials) as they affect plant and soil. Microbes greatly affect soil development. Their activities mediate nutrient status through release, acquisition, retention, and recycling. Microbes, in part, are responsible for soil physical state, tilth, and water retention, by controlling type and quantity of organic materials. These factors, in turn, affect microbial plant symbionts and pathogens. Thus, microbial action in many types of organic fuels is a major biological determinant of site quality. Interactions between forest uses and their residues (fuels) or lack of them bring about changes in both population size and types of soil microorganisms (Bell 1974). Most microbes are dependent on organic materials (plant bodies) either for their energy source or as a growing medium (substrate). Therefore, disruption of the quantity, type, and distribution of humus, litter, and wood imposes controls on their populations. The chemical-physical nature of organic matter also affects microbes. Water content, temperature, and reaction (pH) are all influenced by forest use, especially harvesting and burning (DeByle 1976; Bollen 1974).