地缘合作背景下柬老越发展三角区农进林退动态特征

Dynamic characteristics of agricultural expansion and forest loss in the Cambodia-Laos-Vietnam Development Triangle Area under the context of geo-coorperation

1990年代以来地缘政治向地缘经济转变,“发展三角”应运而生。成立于1999年的柬埔寨—老挝—越南发展三角区在中南半岛多个三国发展区中最为成熟且备受关注。随着越南主导下的地缘经济合作持续推进,该发展三角区覆盖省份持续扩充,并经历了以农进林退为主的土地利用/覆被变化。相较于传统地缘经济研究,有关地缘经济合作与边境土地利用的影响-响应互动研究明显不足。本文选取美国国家开发署SERVIR-Mekong项目1988—2018年共7期土地覆被产品,以5年为间隔,基于GIS空间分析定量刻画该三角区近30年农进林退的时空动态特征。结果表明:①森林、农田和种植园/果园为主要覆被类型,且农进林退是该发展三角区主要的土地利用/覆被变化方式。②农进林退现象先增强后减弱,以发展三角区成立前后(1998—2003年)最为剧烈,且其在越柬境内呈西向与东向趋边性特征,柬越边境最明显。③越南境内农进林退规模最大,但就保护区而言,柬埔寨境内保护区受农进林退影响最大,柬越边境保护区尤甚。④80%以上的农进林退分布在丘陵平原,且具有向高海拔地区发展的趋势;在道路两侧10 km以内呈现随距离衰减的特征,近70%的农进林退发生在道路两侧6 km范围内。本文可为探索地缘经济合作与边境土地利用交叉互动提供研究视角与研究方法上的启示。

“Development Triangle” comes into being with the transition from geopolitics to geoeconomics since the 1990s. The Cambodia-Laos-Vietnam Development Triangle Area(CLV-DTA)founded in 1999, is the most developed among the several DTAs in Mainland Southeast Asia and has attracted much attention from the Association of Southeast Asian Nations(ASEAN), the Asian Development Bank(ADB), and the World Bank(WB) in their tenth biannual summit in 2018. With the continuous advance of geo-economic cooperation led by Vietnam, the involved provincial units in the CLV-DTA continue to expand from seven at its beginning, ten in 2004 and 13 in 2009, and has also experienced land use/cover changes dominated by agriculture expansion and forest loss.Compared with the traditional geo-economic analysis, the investigation in the interaction between geo-economic cooperation and border land use is obviously inadequate and requires in-depth examination. According to the four key nodes(1999, 2004, 2009 and 2018) with geo-influence in the CLV-DTA, seven years’ SERVIR-Mekong land cover data products launched by the United States Agency for International Development with a five-year interval during 1988-2018, were selected and applied to depict quantitatively the spatiotemporally dynamic characteristics of agricultural expansion and forest loss in this DTA in the past three decades with GIS-based spatial analyses. The results showed that:(1) Forest, cropland and plantation/orchards were the main types of land cover. Land use/cover changes are dominated by the way of agricultural expansion and forest loss.(2) Agricultural expansion and forest loss first strengthened and then gradually weakened, especially before and after the establishment of the CLV-DTA(1998-2003). It showed westward and eastward border-prone trends in Vietnam and Cambodia, respectively, with the Cambodia and Vietnamese border most noteable.(3) The area size of agricultural expansion and forest loss was largest in Vietnamese side of the CLV-DTA, followed by Cambodia and Laos,however, various protected areas in Cambodia suffered the most from agricultural expansion and forest loss and those adjacent to the Cambodia-Vietnam border in particular.(4) Over eighty percent of agricultural expansion and forest loss was occurred and re-occurred in the plains along the Mekong River sand its contiguous hilly area, while it also showed an ascending trend in elevation especially in the low-and medium mountains. As the distance to the available roads(including trails) increases, the quantity of agricultural expansion and forest loss declines steadily within 10 km on both sides, following a distance attenuation pattern, with nearly 70% of the occurrence of agricultural expansion and forest loss within 6 km. This study can provide guidances for exploring the cross interaction between geo-economic cooperation and border land use from research perspective and method.