In this paper, secondary forest of Pinus massoniana , coniferous-broad-leaved mixed forest and broad-leaved evergreen forest were taken as research objects, to explore carbon reserve of arbor layer and its spatial dis...In this paper, secondary forest of Pinus massoniana , coniferous-broad-leaved mixed forest and broad-leaved evergreen forest were taken as research objects, to explore carbon reserve of arbor layer and its spatial distribution characteristics. At different succession stages, the sequence of organic carbon content in each organ was secondary forest of P. massoniana > coniferous-broad-leaved mixed forest> broad-leaved evergreen forest. Carbon reserve of arbor layer was the highest in broad-leaved evergreen forest, which was 129.34 t/hm 2, followed by coniferous-broad-leaved mixed forest (95.83 t/hm 2), and the minimum was 85.27 t/hm 2 in secondary forest of P. massoniana . In each stand type, the sequence of carbon reserve of each organ in arbor layer was trunk>root>branch>leaf>bark. Carbon reserve of arbor layer mainly concentrated in trunk, and the proportion to carbon reserve of arbor layer declined from secondary forest of P. massoniana to broad-leaved evergreen forest, while it had increasing relationship in root. In secondary forest of P. massoniana , coniferous-broad-leaved mixed forest and broad-leaved evergreen forest, individual with the diameter more than 20 cm accounted for the majority of carbon reserve in the arbor layer.展开更多
In this paper, the Pinus massoniana forest in the early stage of succession, the coniferous broad-leaved mixed forest in the middle stage of succession, and the evergreen broad-leaved forest in the late stage of succe...In this paper, the Pinus massoniana forest in the early stage of succession, the coniferous broad-leaved mixed forest in the middle stage of succession, and the evergreen broad-leaved forest in the late stage of succession were studied, and the biomass and its spatial distribution characteristics of the tree layer in different succession stages of the ecosystem were discussed. The results showed that the biomass of the arbor layer was the highest in the evergreen broad-leaved forest, which was 292.51 t/ hm2, followed by the coniferous and broad-leaved mixed forest, which was 206.87 t/hm2, and the Pinus massoniana forest, which was 171.76 t/hm2. The biomass of trunks accounted for the largest proportion in the total biomass of the arbor layer, which reduced from the Pinus massoniana forest to the evergreen broad-leaved forest. The proportion of the biomass of roots in the total biomass of the arbor layer increased from the Pinus massoniana forest to the evergreen broad-leaved forest. The biomass of the diameter class above 20 cm in the Pinus massoniana forest, the coniferous and broad-leaved mixed forest and the evergreen broad-leaved forest accounted for a large proportion of total biomass.展开更多
To accurately calculate carbon fixation capacity of P.pubescens forest in Hunan Province and promote the balanced and stable development of P.pubescens forestry in Hunan Province,standard sample plot was set in major ...To accurately calculate carbon fixation capacity of P.pubescens forest in Hunan Province and promote the balanced and stable development of P.pubescens forestry in Hunan Province,standard sample plot was set in major producing area of P.pubescens in Hunan Province,and biomass of 258 P.pubescens was measured according to DBH and age class.Multivariate regression method was used to establish univariate (DBH as independent variable) and bivariate (DBH and age class as independent variables) models of total aboveground biomass and organ biomass of P.pubescens .Model evaluation and test showed that each model accorded with the applicable precision and had the appropriate prediction level.展开更多
A highly focused beam with spot radius of around 1 m and enhanced light intensity is obtained by using an open hollow cone.Two-dimensional and three-dimensional finite-difference time-domain simulations are performed ...A highly focused beam with spot radius of around 1 m and enhanced light intensity is obtained by using an open hollow cone.Two-dimensional and three-dimensional finite-difference time-domain simulations are performed for clarifying light propagation characteristics and the cone geometry dependence of the cone-focused laser light.Two important parameters characterizing the cone-focusing effect are introduced,which are opening angle and cone tip size.By changing these parameters,the laser intensification,field spatial distribution at the cone tip and the near-field transmission can be controlled.Understanding this is quite important in designing the optimum cone shape for fast ignition and determining the basis for using hollow cone targets as devices for generating high energy charged particles.展开更多
基金Sponsored by Forestry Science and Technology Plan of Hunan Province(XLK201806,XLK201925)National Forestry Science and Technology Development Project(KJZXSA2018011,KJZXSA2019009)Operational Subsidy Project of National Forestry Science and Technology Innovation Platform(2019132068)
文摘In this paper, secondary forest of Pinus massoniana , coniferous-broad-leaved mixed forest and broad-leaved evergreen forest were taken as research objects, to explore carbon reserve of arbor layer and its spatial distribution characteristics. At different succession stages, the sequence of organic carbon content in each organ was secondary forest of P. massoniana > coniferous-broad-leaved mixed forest> broad-leaved evergreen forest. Carbon reserve of arbor layer was the highest in broad-leaved evergreen forest, which was 129.34 t/hm 2, followed by coniferous-broad-leaved mixed forest (95.83 t/hm 2), and the minimum was 85.27 t/hm 2 in secondary forest of P. massoniana . In each stand type, the sequence of carbon reserve of each organ in arbor layer was trunk>root>branch>leaf>bark. Carbon reserve of arbor layer mainly concentrated in trunk, and the proportion to carbon reserve of arbor layer declined from secondary forest of P. massoniana to broad-leaved evergreen forest, while it had increasing relationship in root. In secondary forest of P. massoniana , coniferous-broad-leaved mixed forest and broad-leaved evergreen forest, individual with the diameter more than 20 cm accounted for the majority of carbon reserve in the arbor layer.
基金Sponsored by Forestry Science and Technology Plan of Hunan Province(XLK201925,XLK201806)National Forestry Science and Technology Development Project(KJZXSA2018011)Operational Subsidy Project of National Forestry Science and Technology Innovation Platform(2018-LYPT-DW-064)
文摘In this paper, the Pinus massoniana forest in the early stage of succession, the coniferous broad-leaved mixed forest in the middle stage of succession, and the evergreen broad-leaved forest in the late stage of succession were studied, and the biomass and its spatial distribution characteristics of the tree layer in different succession stages of the ecosystem were discussed. The results showed that the biomass of the arbor layer was the highest in the evergreen broad-leaved forest, which was 292.51 t/ hm2, followed by the coniferous and broad-leaved mixed forest, which was 206.87 t/hm2, and the Pinus massoniana forest, which was 171.76 t/hm2. The biomass of trunks accounted for the largest proportion in the total biomass of the arbor layer, which reduced from the Pinus massoniana forest to the evergreen broad-leaved forest. The proportion of the biomass of roots in the total biomass of the arbor layer increased from the Pinus massoniana forest to the evergreen broad-leaved forest. The biomass of the diameter class above 20 cm in the Pinus massoniana forest, the coniferous and broad-leaved mixed forest and the evergreen broad-leaved forest accounted for a large proportion of total biomass.
基金Supported by Forestry Science and Technology Plan of Hunan Province(XLK201925,XLK201806)National Forestry Science and Technology Development Project(KJZXSA2018011,KJZXSA2019009)Operational Subsidy Project of National Forestry Science and Technology Innovation Platform(2018-LYPT-DW-064)
文摘To accurately calculate carbon fixation capacity of P.pubescens forest in Hunan Province and promote the balanced and stable development of P.pubescens forestry in Hunan Province,standard sample plot was set in major producing area of P.pubescens in Hunan Province,and biomass of 258 P.pubescens was measured according to DBH and age class.Multivariate regression method was used to establish univariate (DBH as independent variable) and bivariate (DBH and age class as independent variables) models of total aboveground biomass and organ biomass of P.pubescens .Model evaluation and test showed that each model accorded with the applicable precision and had the appropriate prediction level.
基金supported by the National Basic Research Program of China(Grant No.61359020101-3)the National High Technology ResearchDevelopment Program for Inertial Confinement Fusion of China
文摘A highly focused beam with spot radius of around 1 m and enhanced light intensity is obtained by using an open hollow cone.Two-dimensional and three-dimensional finite-difference time-domain simulations are performed for clarifying light propagation characteristics and the cone geometry dependence of the cone-focused laser light.Two important parameters characterizing the cone-focusing effect are introduced,which are opening angle and cone tip size.By changing these parameters,the laser intensification,field spatial distribution at the cone tip and the near-field transmission can be controlled.Understanding this is quite important in designing the optimum cone shape for fast ignition and determining the basis for using hollow cone targets as devices for generating high energy charged particles.
