It will take more than a month to cut down about 120 pines that have flourished after initial stocks were planted by the area’s first settlers to provide masts for 19th century sailing ships.

Some of the pines, aged from 60 to 90 years, are 40 metres high and have gradually hampered the growth of native vegetation.

South Coast NRM invasive species coordinator Matthew Kennewell said the trees not only damaged the environment, they were a potential hazard, not only to landowners but users of the Luke Pen Walk.

“People don’t realise how dangerous pines are,” he said.

As many were well over 60 years old, they were creating more of a problem than any other species, especially with 25-metre canopies.

Mr Kennewell said some of the larger saplings growing along the Kalgan River were preventing sunlight from reaching the riparian zone (riverbank) and the establishment of native vegetation.

“These pines are an increasing problem in the riparian zone because they out-compete native species and steal nutrients. Directly under the trees you’ll see a mat of decaying pine debris that increases acidity and reduces biodiversity,” he said.

“In some cases, hardy species such as grasses cannot establish themselves there.”

The $120,000 project, delivered by South Coast NRM in collaboration with the City of Albany, Oyster Harbour Catchment Group, local landholders and volunteers, is funded by the State Government.

City of Albany reserves manager Mark Ford said that once the adult pine trees were removed, the task of removing future pine seedlings by volunteers and local landholders would be relatively easy.

“Many of the heavy pine tree limbs are rotten and collapsing, so public safety was another good reason to complete the project,” he said.

Sections of the trees will be retained as saw logs.

Local landowners Alan Jones and Dick Walker have been concerned about the pines for years.

Mr Jones said one tree collapsed suddenly in 1990, just missing a historic shed.