11 Jan 2010

A spray mixture being trialled around Queenstown to rid the high country of wilding pines is attracting interest from around New Zealand, according to One News..

The addition of a simple ingredient in the usual mix of herbicides has had marked success in pines sprayed on Queenstown Hill. Jamie Cowan, co-inventor of the wilding pine brew, says everything tends to run off pine trees and the secret is the crop oil that breaks down the waxy cuticle on the leaf.

The area where the spray mixture was trialled four years ago is now called the ring of death and the researchers hope the dead trees will act as a barrier to stop the spread of seed. That spread of seed further up the hillsides has been turning tussock country into pine forest at an ever increasing rate and traditional controls cannot keep up.

Cowan says previously it would take a crew of about six people two or three days to do a hectare at a cost of up to $5000. "I can do a hectare now in seven minutes at a cost of $650 so it's a massive massive change," he says.

Richard Bowman from the Mid Dome Wilding Trees Charitable Trust says the mixture could potentially save millions. The trial will be completed this year.

The Mid Dome Wilding Trees Charitable Trust promotes and protects the productive, landscape, biodiversity and other values in New Zealand’s tussock lands – particularly at Mid Dome, in northern Southland.

The trust was set up in 2006 to raise the estimated $9 million that will be needed over a 12 year period to remove wilding conifers permanently from Mid Dome and surrounding land. The pines in question are Pinus cortorta and Pinus mugo, species with no commercial value that were planted on about 250 hectares from the 1950s to the 1970s to combat severe erosion.

It is now estimated that over 80,000 ha is now affected by wildings from these plantings (99% contorta pine), although their density is very low over much of this area. Clearance of Mid Dome wildings began in the 1990s and has continued ever since.