| Classification | 1998 | 2002 | 2018 | |||
| Area (km2) | % | Area (km2) | % | Area (km2) | % | |
| Forest | 34.43 | 47.82 | 8.73 | 12.12 | 0 | 0 |
| Plantation | 9.50 | 13.19 | 20.91 | 29.04 | 5.94 | 8.26 |
| Farmland | 14.02 | 19.47 | 22.44 | 31.17 | 39.71 | 55.15 |
| Grassland | 8.00 | 11.10 | 9.25 | 12.85 | 13.50 | 18.75 |
| Bare land | 6.05 | 8.41 | 10.67 | 14.82 | 12.85 | 17.84 |
| Total | 72.00 | 100.00 | 72.00 | 100.00 | 72.00 | 100.00 |