| Criteria | Green vegetation | Tree |
| Level 0 | None | (None or a few) |
| Level 1 | Less than half land area | (None or a few) |
| Level 2 | More than half land area | (None or a few) |
| Level 3 | More than half land area | Less than half land area |
| Level 4 | More than half land area | More than half land area** |