The Forestry Act, 2014, gives a clear definition of a forest as "land under trees with (a) a minimum area of 0.1 hectare and (b) tree crown cover of more than 20 per cent of the total area, or the potential to achieve this cover at maturity, and includes all species of trees".
The Act also provides, under Article 19, for exemptions for tree felling without a tree felling licence, which includes the removal of trees as specified in a grant of planning permission.
Where a landowner is unsure if the trees in question meet the definition of a forest or if the removal of the trees is not covered by a grant of planning, then an application for a tree felling licence must be made. This is regardless of whether the site is to be cleared for non-essential construction. It is an offence to fell trees without a valid tree felling licence, for which upon conviction the land owner may be liable for considerable penalties.