Table 1. Explanatory variables.
| Variable | Source | ||
|---|---|---|---|
| Total Precipitation (mm) | WorldClim (30 arc seconds) http://worldclim.org/version2 [47] | ||
| Climatic variables | Minimum Precipitation (mm) | ||
| Mean Temperature (Celsius) | |||
| Topographic variables | Elevation (m) | NASA Shuttle Radar Topography Mission (SRTM) (90m) | |
| Slope (degrees) | |||
| Accessibility variables * | Distance to Old Plantations (km) | WRI [44] www.globalforestwatch.com | Calculated Euclidean distance to source |
| Distance to Palm Oil Mills (km) | |||
| Distance to Settlements (km) | SEDAC http://sedac.ciesin.columbia.edu/ | ||
| Distance to Major ports (km) | Google Earth | ||
| Accessibility to large cities (population >50,000) (travel time in min) | Joint Research Centre of the European Commission http://forobs.jrc.ec.europa.eu/products/gam/download.php (30 arc seconds) [48] | ||
| Socioeconomic | Population (density per km2) in 2000 / 2010 | SEDAC http://sedac.ciesin.columbia.edu/ (1km) [46] | |
* Models used logs of all the accessibility variables.