Recent Co-occurring Expansion of Rubber Tree Plantations and Land Use/Land Cover Change in Luangnamtha District, Northern Laos

Abstract

Monitoring land use/land cover change at various scales is of foremost importance for the management of natural resources and pivotal to achieve effective environmental governance. The purpose of this study was to classify land use/land cover and to quantify changes in land use/land cover in Luangnamtha district, northern Laos over the past two decades, using remote sensing and Geographic Information System technologies. We used Landsat 5 Thematic Mapper (TM) images from 2000, 2005, 2010 and Landsat 8 Operational Land Imager (OLI) images from 2017. A supervised classification was achieved by applying the maximum likelihood algorithm in the ENVI software. Five land cover classes, namely agriculture, forest, rubber tree, settlement and water were thus identified. The nature and extent of change detected was analyzed on the basis of the land use maps generated for years 2000, 2005, 2010 and 2017. We applied spatial point process theory to analyze spatial relationships between land use classes and with terrain covariables. The overall accuracy of our classifications were 86.8%, 89.3%, 90.4%, and 91.7% for the years 2000, 2005, 2010, and 2017, respectively and the Kappa coefficients were 0.76, 0.85, 0.85, and 0.89, respectively. The results of these classifications indicated that over the 2000 to 2017 period, settled areas increased by 2.35% (5,038 ha), water bodies increased very marginally (0.01% or 20 ha), but that rubber tree cover increased by as much as 7.60% (16,314 ha). During the same period, agricultural land decreased by 0.11% (224 ha) and the forested area shrunk by 9.84% (21,129 ha). Spatial analysis indicates that rubber tree plantations expanded from the lowest part of the landscape, in close spatial association with agricultural land, to increasingly higher locations where it most likely replaced forest. This study confirms that drivers such as government policies for permanent allocation of agricultural land poverty eradication, as well as foreign investments, had a major impact on the expansion of rubber tree plantation in Luangnamtha district from 2000 to 2017.