Biomass and nutrient storage of logging residues of Pinus massoniana plantation
To understand soil productivity maintenance and provide reliable scientific basis for plantation management,biomass and nutrient allocation in different components of logging residues were examined in the clearcutting land of a 31-year-old Pinus massoniana plantation.We measured biomass and nutrient concentration of logging residue's components,and then calculated nutrient storage.The results showed that the total biomass of logging residues was 39.1 t · hm-2,and the storage of carbon,nitrogen,phosphorus,potassium,calcium and magnesium was 18303,101.2,8.3,73.4,96.0 and 24.7 kg · hm-2,respectively.Among different components,the biomass and carbon storage were in the order of sprig (accounting for 25.3% and 23.3% of total biomass and carbon storage,respectively) > branch (21.7% and 21.1%) and taproot (17.1% and 18.5%) > coarse root (11.5% and 12.4%) and leaf (9.2% and 9.1%).Nitrogen,phosphorus,potassium,calcium and magnesium were mainly stored in sprig,branch,and leaf (the sum of those components were 70.5%,76.5%,72.2%,76.2% and 72.6%,respectively),followed by taproot and coarse root.The middle-sized root,small root and fine root had the lowest biomass and nutrient storage.The biomass and nutrient storage of logging residues were enormous,especially in branch and leaf.Therefore,retaining logging residues during forest regeneration is important for forest productivity maintenance.