近30年海南岛橡胶林时空变化分析

【目的】 海南岛为中国第二大植胶区和仅有的两大热区之一,揭示其橡胶林的时空变化规律,对促进我国天然橡胶产业可持续发展有重要意义。【方法】 在Google Earth Engine(GEE)云计算平台上结合Landsat和Sentinel-2系列时间序列影像和橡胶林物候等信息,以5 a为步长提取了海南岛1990—2020年间7期橡胶林分布图,分析了海南岛橡胶林的时空变化规律。【结果】 ①近30年橡胶林面积增长趋势明显,从1990年的34.44万hm²增长至2020年的58.58万hm²,净增70.11%,且整体上呈现 “北增南减”的空间变化趋势;②在市/县尺度,橡胶林面积最大的主要市/县依次是儋州市、白沙县、澄迈县和琼中县,2020年占全岛橡胶林总面积的51.58%,而三亚市、东方市、文昌市及陵水县的橡胶林面积相对较小,2020年橡胶林总面积占比为5.22%;③近30年来,海南岛91.24%的橡胶林都种植在海拔300 m以下地区,97.75%种植地在25°坡度以下,海拔600 m以上几乎没有橡胶林分布,在海拔50~200 m和坡度0~5°的区域橡胶林增长幅度最大;④海南四大国家级自然保护区的实验区或缓冲区内均有少量橡胶林分布,但面积在逐渐下降。其中,霸王岭保护区内橡胶林面积最大,五指山保护区内面积最小,近30年四大保护区内橡胶林面积累计减少了68.02%,保护效果显著。虽然研究期海南岛的橡胶林面积增长非常显著,但集中在低海拔和相对平缓的区域,没有对位于中高海拔地区的热带雨林造成影响;四大国家级自然保护区内虽均有少量橡胶林分布,但递减趋势明显。【结论】 总体而言,海南橡胶林的发展模式良好,没有以牺牲大量热带森林为代价,尚未对当地的生态环境造成严重影响。

Spatio-temporal changes of rubber plantations in Hainan Island over the past 30 years

【Objective】 Natural rubber (NR) is an important strategic material. To promote the sustainable development of China’s natural rubber industry, it is of great significance to reveal the spatio-temporal changes in rubber plantations on Hainan Island, which is the second largest rubber growing area and one of the only two tropical regions in China. 【Method】 Based on the seven-phase distribution maps of rubber plantations on Hainan Island, this study analyzes the spatio-temporal changes of rubber plantations from 1990 to 2020 on the Google Earth Engine (GEE) cloud computing platform. 【Result】 (1) The area of rubber plantations has increased significantly over the past 30 years, from 344 400 hectares in 1990 to 585 800 hectares in 2020 (a net increase of 70.11%), with a general spatial trend that can be characterized as an increase in the north and a decrease in the south. (2) Among these cities/counties, Danzhou City, Baisha County, Qiongzhong County and Chengmai County have the largest rubber plantation area in order, accounting for 51.58% of the total rubber plantation area in 2020, while Sanya City, Dongfang City, Wenchang City, and Lingshui County have the smallest area, accounting for only 5.22% of the total rubber plantation area in 2020. (3) Approximately 91.24% of the rubber plantations in Hainan Island are located below 300 meters above sea level, and few rubber plantations are distributed in areas with elevation above 600 meters; finally, 97.75% of plantations are located in regions with slope less than 25°. (4) In the past 30 years, rubber plantations have increased the most in areas with elevation of 50-200 meters and slope of 0-5°. (5) A small portion of rubber plantations are distributed in the experimental or buffer zones of the four national protected areas, but the total area shows a clear downward trend. Among the plantations studied, the area of rubber plantations in the Bawangling Nature Reserve is the largest and that in the Wuzhishan Nature Reserve is the smallest, with a cumulative decrease of 68.02% in the last 30 years. Although the area of rubber plantations has increased significantly in the last 30 years, they are concentrated in areas of low elevation and are relatively flat and have no impact on tropical rainforests that occur in high elevation regions. 【Conclusion】 In general, the development model for rubber plantations on Hainan Island is sustainable, as it has a minimal impact on tropical forests and the general ecological integrity of the surrounding area.