Soil phosphorus fractions vary with harvest intensity and vegetation control at two contrasting Douglas-fir sites in the Pacific northwest

摘要: Abstract Effects of intensive forest management on soil phosphorus (P) are unclear and may impact long-term site productivity. We assessed changes in P availability over 10 years associated with harvest intensity (bole-only vs. whole-tree harvest) vegetation control treatments (initial (IVC) five years annual (AVC)) using a fractionation procedure. Fractions were characterized at 0–15, 15–30, 30–60 cm depths two coast Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco var. menziesii) plantations strongly contrasting properties near Matlock, WA (young soils formed glacial outwash) Molalla, OR (relatively old igneous residuum exhibiting andic properties). Al Fe concentrations short-range order minerals greater Molalla than Matlock generally decreased depth both sites. observed decreases most total-P P-fraction across the three site. less pronounced inconsistent Decreases total fraction greatest AVC but opposite trends where IVC. There was no difference between change fractions instances, exception some maintained or increased bole-only harvesting. Ten-year responses indicate has limited effects productivity because large size pools relatively small that occurred treatment. IVC larger other highlight important role dynamics following harvesting these