Soil Phosphorus Pools and Availability: Responses to Competing Vegetation Control and Organic Matter Retention in 10-Year-Old Douglas-Fir Stands of the Pacific Northwest.

Competing vegetation control and organic matter retention following forest harvesting can change biogeochemical dynamics of soil nutrient pools and potentially change long-term availability of phosphorus. Soil P fractions from pre-harvest samples and samples obtained ten years after replanting were compared under two different competing vegetation control (initial herbicide application only vs. annual herbicide application) and two organic matter-retention treatments (bole-only vs. whole-tree logging) in two Douglas-fir stands of the Pacific Northwest. Results and implications for long-term soil productivity of managed silvicultural systems in the Pacific Northwest will be discussed.