东江流域1980—2020年森林时空演变特征及水源林改造潜力分析

Spatial and Temporal Variation Characteristics of Forests and Analysis of Potential for Reconstruction of Water Conservation Forests in the Dongjiang River Basin from 1980 to 2020

东江是粤港澳大湾区最重要的水源地,担负着香港地区、深圳和广州3个超大城市的供水任务。东江流域光、热资源充足,雨量充沛,是中国森林覆盖率最高的地区之一,其自1980年以来由于自然因素、政策和经济发展等原因,流域的土地覆盖发生了显著变化,尤其是东江流域面积占比最大的森林的变化更加明显。因此,如何科学规划设计造林工程,依据潜力分析改造水源林已成为社会热点问题。该研究基于1980—2020年东江流域30 m分辨率的土地利用、土壤等数据,结合东江源测站数据和社会经济指标数据,利用空间分析和因子分析等方法,探索东江流域1980—2020年森林覆盖的时空变化及驱动机制,同时对水源林改造的未来潜力进行了分析。①1980—2020年东江流域森林持续减少,总减少量为998.81 km 2,变化多集中于南部和北部,流域北部大量林地转化为耕地,流域南部大量林地转化为城乡、工矿、居民用地;②1980—2020年,影响林地面积变化的因素中,常住人口数量、人口密度、GDP、第二和第三产业产值、工农林业产值、社会消费品零售总额、固定资产投资额、城镇登记失业率等因素占主要成分;③东江流域未来可改造林区域面积为5365 km 2,改造潜力多集中于流域北部及流域东南部。近40 a内东江流域森林面积持续减少,人为活动影响强烈,水源林改造潜力巨大。

The Dongjiang River is the most important water source area in the Guangdong-Hong Kong-Macao Greater Bay Area,supplying water for the three mega-cities of Hong Kong,Shenzhen,and Guangzhou.The Dongjiang River Basin has abundant light and heat resources and sufficient rainfall,and it is one of the regions with the highest forest coverage rate in China.Since 1980,the land cover,especially the forest with the largest proportion in the Dongjiang River Basin,has changed significantly in the Dongjiang River Basin under the influence of natural factors,policy,and economic development.Therefore,how to scientifically plan and design afforestation projects and transform water conservation forests according to potential has become a hot social issue.The study was based on 30 m resolution land use and soil data of the Dongjiang River Basin from 1980 to 2020,and it combined with the data of Dongjiang River Source station and socio-economic index data.The study used spatial analysis and factor analysis to explore the spatial-temporal changes and driving mechanisms of forest cover in the Dongjiang River Basin from 1980 to 2020 and analyze the potential of water conservation forest reconstruction in the future.①From 1980 to 2020,the forest decreased continuously in the Dongjiang River Basin,with a total reduction of 998.81 km^(2).The changes were mainly concentrated in the south and north of the Dongjiang River Basin.In the northern part of the basin,a great deal of forest has been transformed into farmland,while in the southern part of the basin,a great deal of forest has been transformed into cities and countrysides or areas for industry,mining,and housing.②In the period of 1980—2020,the main factors affecting the change of forest area were the number of permanent residents,population density,GDP,output value of secondary and tertiary industries,output value of industry,agriculture,and forestry,total retail sales of social consumer goods,investment in fixed assets,and urban registered unemployment rate.③The area for future reconstruction in the Dongjiang River Basin was 5365 km^(2).The areas with high potential for reconstruction were mainly in the north and southeast parts of the basin.In the past 40 years,the forest area of the Dongjiang River Basin has continued to decrease and is strongly influenced by human activities.Water conservation forest has great potential to be transformed.