基于主成分分析的湘乡市森林健康评价

Evaluation of Forest Health in Xiangxiang City Based on PrincipalComponent Analysis

以湘乡市森林资源“一张图”选定的17434个小班为研究对象,采用主成分分析对筛选的郁闭度、平均胸径、每公顷蓄积、坡度、灾害等级等12个指标进行降维分析,对湘乡市主要森林小班进行健康评价。结果表明:处于“亚健康”状态的森林小班最多,数量和面积占比分别达到了51.83%和51.49%,“健康”及以上状态的森林小班数量和面积占比分别为34.86%和33.01%;不同林分类型小班健康评价综合得分也存在差异(马尾松0.422<湿地松0.447<杉木0.456<慢生阔叶树0.540<速生阔叶树0.574<中生阔叶树0.594),阔叶林与针叶林的健康评价综合得分存在显著性差异(P<0.05)。本研究对湘乡市国土绿化项目建设和林地质量精准提升具有指导意义。

Taking 17434 samples selected from the'one map'of forest resources in Xiangxiang City as the research object,the principal component analysis was used to reduce the dimension of 12 indexes such as canopy density,average DBH,volume per hectare,slope and disaster grade.The health assessment of the main forests in Xiangxiang City was carried out.The results showed that the forest samples in the'sub-health'state were the most,and the number and area accounted for 51.83%and 51.49%,respectively.The number and area of forest plots in the'healthy'and above states accounted for 34.86%and 33.01%,respectively.There were also differences in the health level of forest plots of different forest types(Pinus massoniana 0.422<Pinus elliottii 0.447<Cunninghamia lanceolata 0.456<Slow-growing broad-leaved tree 0.540<Fast-growing broad-leaved tree 0.574<Middle-growing broad-leaved tree 0.594),and there were significant differences in forest health scores between broad-leaved forest and coniferous forest(P<0.05).This study has guiding significance for the construction of land greening projects and the accurate improvement of forest land quality in Xiangxiang City.