Impacts of shortleaf pine-hardwood forest management on soils in the Ouachita Highlands: A review

摘要

Shortleaf pine (Pinus echinata Mill.) is the most ecologically and economically important tree species in the Ouachita Highlands of the southcentral United States. This species can occur in relatively pure stands but most frequently exists in mixed stands with various hardwood species. Because of the diversity of land ownership, public concerns about forest management, and increased intensity of forest practices, the Ouachita Highlands have been a focal point for numerous research projects over the past 20 yr that have studied how forest management affects soils. We summarized information in four fundamental areas: (1) compaction, (2) soil loss, (3) organic matter, and (4) nutrients to better evaluate if and to what degree management practices such as harvesting and prescribed fire modify the productivity, and sustainability of soils in this region. The review indicated that soils with less than 15% rock content or sandy loam textures were susceptible to compaction when harvested during wet weather conditions. Although partial harvesting techniques, such as single-tree or group selection, tended to reduce overall soil disturbance in a stand, it increased soil compaction on primary skid trails by concentrating traffic on fewer skid trails. Compaction on skid trails frequently elevated bulk density to levels that could reduce regeneration success or seedling growth. Using current harvesting systems, soil losses and displacement to streams after harvesting appeared to have little or no effect on long-term soil productivity. Harvesting and prescribed fires significantly, altered nutrient and organic matter contents of the forest floor and mineral soil. However, recovery of these nutrient or organic pools often occurred rapidly after these cultural practices occurred. Little information was available for determining how repeated silvicultural practices over multiple rotations would affect long-term soil productivity in the Ouachita Highlands.