长江经济带森林生态安全评价及时空演变研究

由于森林生态系统的安全关系到人类的生存与发展，因此本文以长江经济带1107个区县为研究对象，运用熵权法、ArcGIS和GeoDA软件、重心分析模型、空间相关分析来分析长江经济带森林生态安全指数（ESI），结论如下：（1）森林状态指数中，权重最高的指标为森林火灾受灾率，其次为森林有害生物成灾率和林地面积比率；在森林压力指数中，权重最高的指标为政府林业投入强度，其次为年度造林比例和自然保护区占比。（2）从全域来看，森林ESI值长江上游 > 中游 > 下游，长江南岸高于北岸。长江经济带森林ESI值总体水平较低，但在2000-2015年间总体呈上升趋势。从各省看，云南省森林ESI值最高，上海市森林ESI值最低。在此15年间，湖南省森林ESI值提高幅度最大（19.77%），江苏省提高幅度最小（0.76%）。（3）各支流流域森林ESI值排序：赣江 > 沅江 > 金沙江 > 乌江 > 湘江 > 汉江 > 嘉陵江 > 岷江。从2000-2015年，八大流域的森林ESI值总体呈上升趋势，其中湘江流域增长幅度最大（20.87%），而金沙江流域增长幅度最小（3.6%）。（4）森林ESI值的重心先后经历了在从南往西、从西往东北和从东北往南等过程。（5）长江经济带森林ESI值有较为显著的集聚性，森林ESI值High-High集聚区域主要分布在四川省和云南省，Low-Low集聚区县主要分布在上海、江苏和安徽，其次在湖北江汉平原、四川成都平原较为集中。（6）基于以上分析，本文建议：①应注重森林火灾、病虫害防治、林业投资、植树造林等工作。②从全域看，生态修复的重点应放在长江下游。从支流流域来看，岷江、嘉陵江和汉江流域应重点加强森林修复工作。③应在上海、江苏、安徽等Low-Low集聚区域加强植树造林和退耕还林的力度，而在四川、云南、江西和浙江等High-High集聚区域适当发展木材加工和林下种植等产业。

Evaluation and spatio-temporal evolution of forest ecological security in the Yangtze River Economic Belt

Because the security of the forest ecosystem is related to human survival and development, this paper took 1,107 districts and counties in the Yangtze River Economic Belt as research objects. The entropy weight method, ArcGIS and GeoDA software, the center of gravity analysis model and spatial correlation analysis were used to analyze the Forest Ecological Security Index (ESI). The following conclusions were drawn. (1) In the forest status index, the highest weighted indicator is the forest fire disaster rate, followed by the forest pest damage rate and forest land area ratio. In the forest pressure index, the indicator with the highest weight is the intensity of government forestry input, followed by the annual afforestation ratio and the proportion of nature reserves. (2) From the perspective of the whole region, the forest ESI values are ranked as the upper reaches of the Yangtze River > the middle reaches > the lower reaches. The forest ESI value in the south bank of the Yangtze River is higher than that in the north bank. The overall level of forest ESI in the Yangtze River Economic Belt is relatively low, but it generally showed an upward trend from 2000 to 2015. From the perspective of each province, Yunnan Province has the highest forest ESI value (19.77%), while Shanghai has the lowest one. In the 15-year period, the forest ESI value in Hunan Province has increased the most, and Jiangsu has the smallest increase (0.76%). (3) The forest ESI values in each tributary are in the order of Ganjiang > Yongjiang > Jinshajiang > Wujiang > Xiangjiang > Hanjiang > Jialing River > Yongjiang. From 2000 to 2015, the forest ESI values of the eight major river basins generally showed an upward trend, among which the Xiangjiang River Basin had the largest increase (20.87%) while the Jinsha River Basin had the smallest increase (3.6%). (4) The center of gravity of the forest ESI value has successively experienced the process from south to west, west to northeast, and northeast to south. (5) The forest ESI value of the Yangtze River Economic Belt has a relatively obvious agglomeration. The forest ESI values high-high concentration areas are mainly distributed in Sichuan and Yunnan Provinces, and the low-low agglomeration areas are mainly distributed in Shanghai, Jiangsu and Anhui, followed by Hubei Jianghan Plain and Sichuan Chengdu Plain. (6) Based on the above analysis, this paper suggests that i) attention should be paid to forest fires, pest control, forestry investment, and afforestation. ii) From the perspective of the whole region, the focus of ecological restoration should be on the lower reaches of the Yangtze River. From the perspective of tributaries, Minjiang, Jialing and Han rivers should focus on strengthening forest restoration. iii) It is necessary to strengthen the afforestation and conversion of farmland to forests in the low-low agglomeration areas such as Shanghai, Jiangsu and Anhui, and to appropriately develop wood processing and under-forest planting industries in the high-high agglomeration areas such as Sichuan, Yunnan, Jiangxi and Zhejiang.