立地管理措施对2代26年生杉木林生产力的影响OA北大核心CSTPCD

The effects of different site management strategies on the productivity of a replanted second-rotation Chinese fir(Cunninghamia lanceolata)plantation were studied after establishing a fixed experimental site in a 29-year-old Chinese fir plantation(originating from ordinary local Chinese fir seeds)with a site index class of 20 in the first rotation.After harvesting the first rotation plantation,seedlings from a second-generation Chinese fir seed orchard were used to establish a second-generation Chinese fir experimental plantation that contained five different harvest residue treatments.The effects of the treatments on the productivity of second-generation Chinese fir forest plantation were studied at 26 years after establishment.The results showed that the average stand volume of the 26-year-old second rotation Chinese fir plantation was 666.312 m3·hm-2,average timber output was 536.805 m3·hm-2 and mean annual stand volume increment was 25.627 m3·hm-2·a-1.The stand volumes and timber output orders for the different treatments were as follows:stem and bark harvest treatment(BL2)>doubling slash treatment(BL3)>burning treatment(SB)>whole-tree harvest treatment(BL1)>removal of slash treatment(BL0).The quantity of large diameter wood produced after the five different treatments was over 65.52%;however,there were no significant differences among the five treatments.There was no productivity decline in the 26-year-old second-rotation Chinese fir plantation in this study,which differs from the results reported by previous studies.There were also no significant differences in productivity among the different harvest residue treatments,which may be related to factors such as a higher site index,sufficient soil nutrient reserves,and the use of genetically improved seedlings.The results suggest that retaining residues following stem and bark harvesting,matching species with the site(planting Chinese fir at 20 or higher site index class sites),and the use of genetically improved planting stock are effective ways to alleviate the problem of soil decline in Chinese fir over successive rotations and sustainably manage Chinese fir large-diameter knot-free timber plantations.