Under the ETS, forest land is defined as being at least 1 hectare with forest species that has, or is likely to have tree crown cover of more than 30% on each hectare. Forest land does not include land that will have an average width of less than 30 metres.

Forest species are trees capable of reaching five metres in height at maturity in the place they are growing, excluding tree species grown primarily for the production of fruit and nut crops.

The ETS classifies forests differently depending on when they were first established – after 1989 (post-1989 forest land) or before 1990 (pre-1990 forest land).