老挝北部刀耕火种农业变化及植被恢复效应  

Monitoring the spatio-temporal dynamics of swidden agriculture and fallow vegetation recovery using Landsat imagery in northern Laos

作　　者：廖谌婳[1,2] 封志明[1] 李鹏[1] 张景华[1] 

机构地区：[1]中国科学院地理科学与资源研究所,北京100101 [2]中国科学院大学,北京100049

出　　处：《地理学报》2015年第4期591-603,共13页Acta Geographica Sinica

基　　金：国家自然科学基金项目(41301090;41271117;41401625);中国科学院战略科技重点项目(2012SJ008;2014SJCB006~~

摘　　要：基于“3S”技术研究了老挝北部1990—2011年刀耕火种农业时空变化的总体特征及其不同阶段土地利用变化、刀耕火种农业土地利用强度（利用频率、轮歇周期）及其对休耕期次生林自然恢复过程的影响。结果表明：①1990—2011年，刀耕火种农业总体上呈增加趋势，由15．38万hm^2增加到了23．84万hm^2，增幅为54．98％；刀耕火种农业的增加主要发生在波乔省南部和琅勃拉邦省，减少主要发生在丰沙里省。②刀耕火种农业主要分布在海拔高度500～1500m、坡度10°-30°的地区，增加主要发生在海拔高度500～800m、300～500m和800～1000m的地区，以及坡度10°-20°和20°-30°的地区。刀耕火种农业的地类转变方向主要是有林地，转入和转出率均高达80％。③2000-2011年，老挝北部刀耕火种农业的利用频率约为2～3次，时间间隔1—7年不等；轮歇周期有所缩短，变化幅度不大。④老挝北部刀耕火种农业的休耕期次生林自然恢复状况与轮歇周期关系显著，二者相关系数为0．9698。当轮歇周期长达10年时，次生林能够恢复到该区域有林地NDVI的平均水平。Swidden agriculture is an age-old, prevalling but controversial farming practice in Montane Malnland Southeast Asia (MMSEA). In the uplands of northern Laos, swidden agriculture has become the predominant land use type for centuries. The swidden system has undergone dramatic transformations since the mid-1990s. The debate on the change of swidden cultivation is linked to global critical issues of land use/cover change, biodiversity and climate change. Since the implementation of Reducing Emissions from Deforestation and forest Degradation (REDD) by the United Nations, an increasing attention has been given to swidden agriculture in the humid tropics nationally and internationally. However, very little is known or reported about the explicit spatial information of swidden agriculture and the consequences of the transitions at macroscopic scale. For the purpose of understanding the spatial and temporal dynamics of swidden system, the intensity of swidden use and fallow forest recovery in northern Laos, in this study, the swidden agriculture in 1990, 2002, and 2011 were mapped and delineated with Landsat Thematic Mapper (TM) and Enhanced Thematic Mapper plus (ETM+) imagery (30 m) with a decision tree classification method, followed by the analysis of spatio-temporal changes of swidden agriculture. Then, annual successive TM/ETM+ images during the period 2000-2010 were used to delineate the dynamics of burning phase and cropping phase. Subsequently, the burned pixels derived in 2000 were compared with those in the following years (2001-2011) under ArcGIS 10.0 to investigate the temporal development, land use frequency and swidden cycle with time-series Landsat-based NDVI data. Finally, as the swidden cycle changed from 1 to 11 years, the fallow vegetation recovery process was studied. The results showed that: (1) From 1990-2011, the area of swidden agriculture increased by 54.98%, from 153,800 to 238,400 ha. The increased swidden cultivation were malnly found in Luang Prabang and southern Bokeo; while the decreased p

关 键 词：刀耕火种农业 时空变化 轮歇周期 利用频率 植被恢复 老挝北部 

分 类 号：K334[历史地理—历史学] S-0[历史地理—世界史]