Poisoning team battle to kill pines

00:58, Aug 07 2014

An ambitious project is transforming the look of Abel Tasman National Park, as wilding pines are poisoned by the hundreds of thousands.

Three years ago the Abel Tasman Birdsong Trust launched an audacious project to rid the park of the invasive pines, which crowd out native trees and the food they provide for native birds.

It is part of the trust's mission to restore native bird populations in the park, and it also helps to lower the risk of bushfires spreading.

The manager of the project, R&D Environmental director Andrew Macalister, said his crews had "made the impossible possible" and "broken the back" of the task.

The trust had spent $509,000 on the project to date, and planned to spend another $100,000 on the final push this summer, trustee Pam Holyoake said.

"We all thought [removing the pines] was a project that was beyond our reach, but it has been one of the most successful in New Zealand."


Over the past three summers, about 40 rugged men have tramped through the park lugging 20-kilogram packs, on what Macalister calls a "search and destroy mission" to eradicate the familiar pinus radiata and pinus pinaster, the maritime pine.

Equipped with power drills and hand-held GPS units, they are dropped at a beach at 7am and tramp through thick, untracked bush to trees marked as waypoints on their GPS.

From ground level, the pines may be hidden by the five-metre-high forest canopy.

The teams drill up to eight holes in the trunk of each wilding pine and inject 10 millilitres of herbicide into each hole.

Macalister said leaving the tree to die in place was preferable to felling it, because when the tree fell it could wipe out ground cover plants, leaving the exposed earth vulnerable to opportunistic pine seeds.

The pines are concentrated in the coastal strip of the park.

"The coastal areas were subject to burning and farming, and that created the opportunity for the pines," Macalister said. "That's also the area that people see and value, so it's very important.

"If you left them, in 50 years all you'd see south of Anchorage would be a pine forest."

He describes the project as "reclaiming the skyline" - and from the air, you can see why. The poisoned pines show up as grey and ginger ghosts dotting the otherwise verdant green of the park's flora.

Macalister mostly uses detailed aerial photographs to find and map the pines, but during a helicopter reconnaissance on Monday he found two stands of radiata that he hadn't seen in photographs, "basically in the middle of nowhere", about halfway between Totaranui and Separation Point.

"There will always be missed trees", he said. "We'll target the missed coning trees this year so from then on, there should be no more seeding trees, just seedlings."

For every mature tree that has been poisoned, he estimates his workers have yanked out another two seedlings.

Macalister is full of praise for the "young, fit guys working really long, hard days in the park", who do the work because they care about the project. Since 2011 he has used contractors from seven firms across the top of the south, who otherwise work in possum control crews, forestry crews and weed control crews.

Project Janszoon will take over the work of seedling removal so the project's valuable gains are not lost after the final push this summer.

"With the right people and the right resources and the emerging technology, some seemingly insurmountable challenges are achievable," Macalister said.

The Nelson Mail