Bay of Plenty Regional Council says a trial to convert gorse-covered hills to pine forest in the Rotorua area could become a template for future land use changes.
An 18.5-hectare Maori land block near the Rotorua airport is being converted to trees in an effort to reduce the amount of nitrogen leaching into Lake Rotorua.
Research by the council has found that gorse is leaching about 43 tonnes of nitrogen into the Rotorua lake catchment each year, making it one of the biggest polluters, next to pastoral farming.
Farming adviser John Paterson says that if the gorse in the catchment area was removed and replaced with pine trees, it could prevent about 41 tonnes of nitrogen a year from going into the lake.
He says the trial will look at best practice for the change in land use, and at ways of limiting the initial spike of nitrogen released when the gorse is removed.