中南半岛森林覆被变化研究进展

中南半岛森林覆被是热带地区极为重要的自然资源，对当地生态环境和社会经济发展都有重要影响。本文从遥感监测与制图、时空变化格局、影响因素和生态环境效应4 个方面，系统总结和评述了中南半岛森林覆被变化的研究进展，并对研究问题和发展方向进行了讨论。研究表明：①中南半岛森林覆被遥感监测数据源由光学遥感逐渐转向雷达遥感，监测方法向采用多分类器和多源信息转变，监测对象主要是天然森林覆被，人工林监测仍面临多重困难；②1980-2010 年期间，中南半岛不同地区森林覆被变化时空差异明显，其中，在1990 年前森林覆被面积为净增加，之后净减少；在空间上，泰国、老挝、缅甸和柬埔寨森林面积在1990 年后均持续减少，只有越南呈增长趋势；③中南半岛森林覆被变化的直接驱动因素主要为经济林扩张、刀耕火种农业、道路建设和商业采伐，间接驱动因素包括人口、社会经济和政策等因素，主要表现为森林数量变化、森林退化和森林再生/恢复等方面，其程度与干扰方式、强度、频率直接相关；④中南半岛森林覆被变化的生态环境效应主要体现在水分效应、大气环境效应、土壤效应和生物效应4方面。

Progress of research on forest land cover change in the Indo-China Peninsula

Forest cover is an extremely important natural resource in the Indo-china peninsula. It is of significant importance to the local ecological environment and socioeconomic development. This paper systematically summarizes and reviews research progresses on forest cover change in the Indo-china peninsula with respect to remote sensing monitoring and mapping, spatial-temporal variations, driving forces and ecological environmental effects, and discusses existing problems in these researches and trends of development. The results show that: (1) forest cover monitoring in the Indo-China peninsula have changed from optical remote sensing to radar remote sensing, and monitoring methods from single to multiple classifiers and data sources. The monitoring objects were mainly on natural forest covers, while monitoring of planted forests still face many difficulties; (2) forest cover area increased from 1980 to 1990 and declined since 1990. Among the five member countries of the Indo-China Peninsula, Thailand, Laos, Myanmar and Cambodia had decreased forest cover after 1990, while Vietnam is the only country where forest transition has occurred after the 1990s. The regional differences of forest cover change were significant in the Indo-China peninsula; (3) direct driving factors of forest cover changes were mainly cash plantation expansion, slash-and-burn cultivation, road construction and commercial logging, while indirect driving factors mainly included population change and socioeconomic and policy factors. The impacts on forest cover change were reflected in forest cover area, forest degradation/regeneration, and forest landscape ecology. The extent of impact was directly related to the pattern, intensity and frequency of disturbances; (4) the ecological and environmental impacts of forest cover change were mainly on water, atmosphere, soil and biology. Impact on water is focused on water retention of canopy and soil moisture regulating. Impact on the atmosphere is mainly on greenhouse gas emission and regional climate change. Impact on soil is largely on soil carbon emission and soil erosion. Biological impact is primarily on biodiversity. The forest cover change research in Indo-China peninsula has the following problems: (1) forest cover remote sensing monitoring was mainly on global area of forest cover, while studies on different forest types were rare, especially on local typical plantations. Research on forest degradation and regeneration was also inadequate; (2) the research of spatiotemporal patterns of forest cover change was mainly large-scale, while small-scale studies, especially comparative study of different countries or regions, were fewer; (3) research on the driving mechanisms of forest cover change was mostly qualitative or semi-quantitative, while integration of various data and quantitative analysis were inadequate. In view of these problems, future research on forest cover change of the Indo-China peninsula could be strengthened in the following three areas: (1) to explore or improve the monitoring methods of forest cover change, especially forest cover change in typical regions or typical forest types; (2) to enhance multi-scale, comprehensive and comparative study of forest cover change in the Indo-China peninsula; (3) to enhance quantitative study of forest cover change and the driving mechanisms.