New Zealand’s Conservation Department (DoC) hopes the New Zealand Defence Force will clear trees on Army land and that the Horizons Regional Council and private landowners will help. Source: Wanganui Chronicle
The Karioi Forest is one of the original seed sources for the infestation of Pinus contorta in Tongariro National Park.
The few remaining trees there are being removed as part of a 10-year maintenance program.
Forestry company Ernslaw One regional manager Steve Couper said Pinus contorta would be felled with other pines, and trees growing in swamps sprayed by helicopter.
But 100% eradication cannot be guaranteed.
The trees have spread from their original seed sources to the Erua and Tongariro forests and to Army land near the Desert Rd.
Pinus contorta was one of many species planted in the Karioi and Rangataua forests by the New Zealand Forest Service. The plantings were an experiment and may have been done in the early 1950s.
By the early 1960s, ecologist Ian Atkinson, employed to survey vegetation in Tongariro National Park, could see the pines were a problem.
He said they had the potential to smother practically all the vegetation in the park, from the tussock grasslands to high up on the mountains, if left unchecked.
They grew in gravel fields where native plants didn’t survive, and at higher altitudes than native beech trees.
They were growing fast, and seeding profusely.
Wanganui ecologist Colin Ogle helped Dr Atkinson with the survey and said the war against Pinus contorta had been a long one and not over yet.
Ridgway Lythgoe, now living in Wanganui, worked for Lands and Survey from 1978-1984 and remembers some of the Tongariro battles.
At that time he was supervising volunteer groups of 30 people at weekends.
“The infestations were so thick that we would do less than a hectare in a weekend. I remember driving back to Ohakune after one of them, with a sore back, thinking ‘We are not winning on this’,” he said.
“We were doing eight or nine weekends a year and the rest of the time the plant was just racing away.”
After that contracted Fijians tackled the pines in big groups.
It was hard work, on rough ground, but it got rid of the big groups of trees in the park.
DoC’s Tongariro animal and plant pest manager, Danial van der Lubbe, is working on what’s left of the problem now.
He’d like to see every tree gone but DoC’s resources stretched only to two weeks’ staff time, five days of spraying from a helicopter and three or four weekends’ work by groups of volunteers each year.
This year the focus was on blocks near Turangi and Erua and on an area near Whakapapa.
The budget was too small and there were too many other weeds for DoC to do more. Its new partnership rangers had the job of drumming up more volunteers and more funding.
