D. Andrew Scott and Felipe Sanchez. USDA Forest Service, Southern Research Station, 2500 Shreveport Highway, Pineville, LA 71360
Maintaining and improving forest soil productivity is a goal of most forest land management entities, and is a vital component of sustainable forestry. Forests are relatively long-lived, and simple measurements of yield response to soil variables are confounded by tree age, climate, and competing vegetation. The USDA Forest Service initiated a study in 1989 to specifically explore the fundamental relationships between forest management activities, soil properties and processes, and tree growth. The study was designed to explore basic relationships among soil fertility, soil porosity, and tree various ecosystem processes. The core experimental design is a 3x3 factorial design with three levels of carefully and evenly applied soil compaction (none, moderate, and severe) and three levels of organic matter removal at the time of harvest (stem only, whole-tree, and all aboveground organic matter). The relatively large plots (0.4 ha) are split, with one half receiving no vegetative competition control and the other receiving manual and chemical competition control. Currently, 62 core locations have been installed throughout the United States and Canada, while over 40 forest industry-university affiliate sites have been installed to evaluate applied and ameliorative practices on soil productivity. The oldest and greatest number of locations (13) is in the Southern Coastal Plain. Soil properties and processes and tree growth have been monitored for 9-15 years on the 13 core study sites. Early measurements have shown a surprising lack of tree growth response to soil compaction on any site. Organic matter removals have had varying effects on tree growth and productivity, and appear to be related to soil phosphorus and potassium deficiencies. Long-term research will be needed on these sites to monitor and understand how soil organic matter and fertility and soil physical properties respond over time to these pulse disturbances, to ecosystem diversity, and to changes in climate.
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Back to The ASA-CSSA-SSSA International Annual Meetings (November 6-10, 2005)