New method used in war on pines

20:44, Apr 26 2012
Peter Raal
SHOWING OFF THE SPRAY: Department of Conservation ranger Peter Raal displays the effects of a new herbicide application method on wilding pines.

The battle against wilding pines has just got easier, thanks to the introduction of a new herbicide application method.

Twizel Department of Conservation biodiversity threats ranger Peter Willemse said the organisation's new approach of applying a specific herbicide directly onto tree bark had radically speeded up work on wilding pines and other invasive tree species.

"It's effectively chemically ring-barking the tree," he said.

"The labour time spent killing a wilding tree has reduced by 75 per cent in most cases."

Some contractors were modifying spray gear to make the method even more efficient, Mr Willemse said.

"This is the way forward. It's taken about four or so years to develop the technique, but since we began using it operationally about 18 months ago, we've really noticed the results. We're getting far more covered with the same amount of money."


Mr Willemse and Otago-based DOC ranger Peter Raal have developed the method over the last four years.

Wilding pines are one of the most invasive species in the Mackenzie and Waitaki basins, infesting more than 200,000 hectares of conservation land.

"The beauty of this technique is that you can use it all year-round.

"You're not restricted to only the growing season. The only thing stopping us is rain. You just spray and walk away," he said.

The method is also being used aerially by applying the brew directly onto the tree by two-metre long hand-held wand out the door of a helicopter.

Mr Willemse spoke about the new technique to delegates from all over New Zealand at a conference on wilding pines in Twizel last week.

"We're going through about 1000 litres of the stuff a month. We're working with organisations such as Scion to better develop the product and provide a more eco-friendly mixture at a reasonable price," he said.

"We will talk to private landowners about its benefits, once we've fine-tuned a few things. It's a win-win for everyone."

The Timaru Herald