Understanding the drivers of deforestation and agricultural transformations in the Northwestern uplands of Cambodia

Abstract

At the end of the 1990s, the Northwestern uplands of Cambodia were one of the last forest frontiers of the country. In a region that was the last Khmer Rouge stronghold, the opening of former conflict zones after a peace agreement initiated a vast movement of agricultural colonization. This movement was economically triggered by high market demand for agricultural commodities such as maize and cassava and fueled by a massive flow of spontaneous in-migration of land-poor farmers from lowland regions around the entire country. Focused on four upland districts along a pioneer front of Northwestern Cambodia, we analyzed historical trajectories of land use/ cover changes using a chronological series of Landsat data from 1976 to 2016. We identified key drivers of deforestation using demographic data and qualitative information from local actors and other relevant stakeholders. We found a 65 percent forest cover loss due to conversion by smallholders into agricultural land for maize and cassava cultivation over a period of 15 years. The underlying mechanisms of land use change were further investigated to understand the diversity of individual farm trajectories and decision-making processes in relation to land conversion. These elements of diagnosis are essential to engage farming communities in innovative land use systems and to develop sustainable alternatives to boom crops that have led to the current situation of land degradation and economic instability.

Remote Sensing Products and Services in Support of Agricultural Public Policies in Africa: Overview and Challenges

“…The scientific studies linking land changes to agricultural public policies are also weak compared to those dedicated to environmental policies (e.g., Lein, 2012). Based on classifications of high resolution images (e.g., Landsat and SPOT), studies have shown the effect (or the absence of an effect) of agricultural policies on land cover and land use in Syria (Ibrahim et al, 2014), the Peruvian Amazon (Chavez et al, 2014), Cambodia (Kong et al, 2019), or in the Yucatan region in Mexico (Turner, 2010). Using MODIS NDVI time series, Lein (2012) showed how an agricultural tax free ordinance issued in 2006 changed the adoption of multiple cropping practices in China, while in Brazil, Arvor et al (2011) developed satellite-derived indices to describe the agricultural dynamics in Amazonia between 2000 and 2007 in relation to the existing public policies.…”

Foreign demand for agricultural commodities drives virtual carbon exports from Cambodia

“…increasing accessibility to previously remote areas through roads and other infrastructure, which tend to cause rapid land degradation due to intensive resource extraction (Hall 2011). Rapid land use and land cover changes (with high carbon loss) along the Thai border are explained by the opening of a former conflict zone, as this region was the last Khmer Rouge stronghold (Kong et al 2019). After peace agreements, this area experienced a rapid influx of land-poor farmers from lowland regions of Cambodia.…”

“…After peace agreements, this area experienced a rapid influx of land-poor farmers from lowland regions of Cambodia. Refugees also came searching for land to establish cash-crop farms for maize and cassava production, triggered by high market demands of these crops at the time (Kong et al 2019). Mahanty (2019) links more recent deforestation trends along the Vietnamese border to both direct and indirect effects of the of ELCs.…”

“…In order to assess how landcover maps vary in terms of forest cover and forest loss, we compared existing land cover classifications of Cambodia on a national and sub-national scale. Even though the Version-2 land cover classifications by SERVIR-Mekong have high overall accuracy (94%; Saah et al (2020)), we compared the classification with SERVIR-Mekong Version 1 (from nowon called Version 1), Kong et al (2019), and Venkatappa et al (2019). Version 1 was partly resampled by us to identify forest plantations (see supplementary information and figure S5-7).…”

An examination of forest cover change at Angkor, Cambodia, using satellite imagery, interviews and interpretation of historical events

“…There is no scarcity of research examining the relationship between patterns of land use and land cover (LULC) and influencing processes (Bürgi et al, 2004;Cassidy et al, 2010;Kong et al, 2019;Plieninger et al, 2015;Seto et al, 2002). However, the complexity of such relationships, including the variability observed at different spatial and temporal scales is often less well understood.…”