The re-introduction of felling licences brings to an end decades of destruction across Northern Ireland, the Woodland Trust has said.
New legislation means licences are now required for the felling of woodland over 0.2 hectares (0.5 acres), bringing the region in line with the rest of the UK for the first time in 45 years.
Patrick Cregg, director of the Woodland Trust, said: "It's no secret that we're one of the least-wooded countries in Europe, with just 7% woodland cover. This very basic legal protection will now put our trees and woods on a more secure footing.
"It's good news for people, for wildlife and for the future of our natural environment."
It is hoped the new laws will protect up to 50,000 hectares of privately owned woods and forests.
Five-year felling licences will be administered by the Department of Agriculture's Forest Service, which manages about 76,000 hectares of woodland. A key component is the inclusion of a felling management plan which details how the felled area will be regenerated or re-planted.
Mr Cregg added: "In the late 1960s a decision was made to abandon the need for felling licences here in Northern Ireland. And this lack of legal protection has resulted in decades of destruction to our trees and woods. This month, some 45 years on, sees the welcome reintroduction of felling controls, bringing the province back in line with the rest of the UK."
Licences will not be required for the felling of trees in gardens, city parks or churchyards; or for fruit trees. Removal of scrub consisting of young trees (up to eight centimetres in diameter); lopping or topping trees; or felling a small volume of timber (up to five cubic metres in a calendar quarter) will also be exempt.
Agriculture Minister Michelle O'Neill described the new measures as a key milestone and said implementation of felling legislation would go a long way to meeting statutory commitments to promote woodlands.
There is no charge for a felling licence.