未来3种气候模式下的阔叶林森林空间结构优化

全球气候变化对森林生态系统造成了重大影响，构建气候模式下的阔叶林森林空间结构优化模型可应对气候变化，同时进行林木数量上的恢复和保护。选择湖南省龙虎山林场1 600 m²的固定样地，模拟林木在林分中的位置，采用改进多族群PSO算法并结合气候敏感的树高-胸径的广义模型，开展RCP2.6、RCP4.5、RCP8.5气候情景下15 a后森林空间结构优化研究。结果表明，RCP2.6气候情景下样地择伐4株树后效果最明显，林分调整后的混交度、林层指数、开阔比数、大小比数以及林分均质性指数均增加，竞争指数、角尺度以及空间密度指数均下降，其中竞争指数和开阔比数变化最大，为-26.877%和28.148%;RCP4.5气候情景下该样地择伐8株树后效果最明显，林分调整后的混交度、林层指数、开阔比数、大小比数、均质性指数等均增加，竞争指数、角尺度以及空间密度指数均下降，其中开阔比数和均质性指数的变化最大，为21.43%和38.01%;RCP8.5气候情景下该样地择伐7株树后林分优化为最佳状态，林分调整后的混交度、林层指数、开阔比数、大小比数、均质性指数均增加，竞争指数、角尺度以及空间密度...

Spatial Structure Optimization of Broad-Leaved Forests Under Three Future Climate Scenarios

Global climate change has a major impact on forest ecosystems.The objectives of this study were to construct a broad-leaved forest spatial optimization model under climate scenarios to cope the climate change,at the same time to restore and protect forest quantity.A 1 600 m² fixed plot in the Longhushan Forest Farm of Hunan Province was selected to conduct the experiment.The locations of the forest trees in the stand were simulated.Combined with the climate-sensitive tree height-diameter generalized model,the improved multi-swarm PSO algorithm was adopted to research forest spatial structure under the three future climates scenarios (RCP2.6,RCP4.5,RCP8.5) after 15 years.Cutting 4 trees in the sample plot had the best effect under the RCP2.6 climate scenario,and the mingling degree,stand layer index,openness comparison index,neighborhood comparison and homogeneity index increased after adjustment,while the competition index,uniform angle index,spatial density index decreased.The competition index and openness comparison index exhibited the most significant changes,which were -26.877% and 28.148%.Cutting 8 trees had the best effect under the RCP4.5 climate scenario,and the mingling degree,stand layer index,openness comparison index,neighborhood comparison and homogeneity index increased after adjustment,while competition index,uniform angle index,spatial density index decreased.The openness comparison index and homogeneity index had the greatest changes,which were 21.43% and 38.01%,respectively.Cutting 7 trees had the best effect under the RCP8.5 climate scenario,and the mingling degree,stand layer index,openness comparison index,neighborhood comparison and homogeneity index increased after adjustment,while competition index,uniform angle index,spatial density index decreased.The competition index and homogeneity index had the greatest changes,which were -10.34% and 29.23%,respectively.The adjusted forest stand structure is better than before under the three climate scenarios,The stand growth is more sensitive under the RCP2.6 climate scenario.