Soil carbon and nutrient pools in Douglas-fir plantations 5years after manipulating biomass and competing vegetation in the Pacific Northwest

摘要: Abstract We assessed changes in mineral soil total carbon (C) and nutrient (exchangeable Ca, K, Mg, N) pools to 60 cm depth 5 years after manipulating biomass competing vegetation at two contrasting Douglas-fir plantations (Matlock, WA, Molalla, OR). Biomass treatments included whole-tree (WT) bole-only (BO) harvest, control (VC) were applied as either initial or annual herbicide applications. There main effects of removal VC on the absolute change some elements both sites, but significant more prevalent lower quality Matlock site than Molalla site, generally confined top 15 cm soil. In all cases, treatment associated with increases C nutrients following BO combined little WT treatments. At (0–60 cm) C, N, Ca significantly increased treatments, Mg K decreased regardless treatment. did not response during study period. Correlation analyses indicated influence early growth likely because water is limiting availability that was correlated indicating harvesting could crop development future. These results indicate low potential for intensive management practices reduce nutrients, there uncertainty long-term may have influenced storage other