基于林分空间结构调整的思茅松天然林碳增汇经营技术优化

Optimization of Carbon Sequestration Management Technology of Pinus kesiya var. langbianensis Natural Forest Based on the Adjustment of Forest Stand Spatial Structure

  • 摘要: 以普洱地区2007年、2012年一类调查结果为数据源,将2012年设置样地内的126株树作为研究对象,以间伐为抚育措施,建立以林分空间结构调整优化和碳储量为目标的间伐模型;约束条件取空间结构的角尺度、混交度、开敞度、林层指数和竞争指数,非空间结构的树木大小、树种多样性,以及碳储量变化情况;设置9个间伐强度梯度,以多目标规划的思路对间伐模型进行求解。结果表明:思茅松天然林林分空间结构指标与目标函数值的关联程度排序为开敞度 > 林层指数 > 角尺度 > 混交度 > 竞争指数;随着间伐强度增大,林分各参数变化幅度均增大。在45%的间伐强度下,林分优化效果最佳,共采伐49株树,林分的树种组成多样性和直径结构均匀程度未改变。林内透光程度提升了31.27%,林分垂直结构丰富度提升了27.68%,角尺度指数值降低了19.77%,树种空间隔离程度提升了20.63%,林木间竞争程度下降了44.27%。目标函数值从139.64增加到658.51,比间伐前提升了近乎4.5倍,碳储量比上一期增加了35.35 t/hm2。在保证林分碳储量的同时,显著提高了林分在林木竞争程度、垂直结构、树种隔离程度和林地光照条件等方面的表现,整体林分状态朝更优质的方向转变,对思茅松天然林以及相似林分的可持续发展经营具有重要的参考意义。

     

    Abstract: One hundred and twenty-six trees in the sample plots set up in 2012 were taken as data sources in 2007 and 2012 in the Pu'er area, and intercalation was used as a nurturing measure to establish an intercalation model with the spatial structure of the stand adjusted and optimized and carbon storage as the target. The constraints were angular scale, mixing degree, openness, stand index and competition index of spatial structure, tree size and species diversity of non-spatial structure, and carbon stock change. Nine interharvesting intensity gradients were set, and the interharvesting model was solved with the idea of multi-objective planning. The results showed that the correlation between the spatial structure indexes and the objective function values of Pinus kesiya var. langbianensis natural forest stands was openness > story index > angular scale > mixing degree > competition index; the changes of all parameters in the stands increased with the increase of intercutting intensity. The stand was optimized best at 45% intercutting intensity, with 49 trees harvested, and the diversity of species composition and uniformity of diameter structure of the stand remained unchanged. The degree of intra-forest light transmission increased by 31.27%, the vertical structure richness of the stand increased by 27.68%, the angular scale index value decreased by 19.77%, the spatial segregation of tree species increased by 20.63%, and the competition among trees decreased by 44.27%. The target function value risen from 139.64 to 658.51, which is almost 4.5 times higher than that before the intercutting, and the carbon stock increased by 35.35 t/hm2 compared with the previous period. While ensuring the carbon stock of the stand, the performance of the stand in terms of the degree of competition among trees, vertical structure, species isolation and light condition of the stand was significantly improved. The overall stand condition changed to a higher quality direction, which is an essential reference for the sustainable development and management of natural forests and similar stands.

     

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