Volunteers working in Okura Bush want boardwalks built over wet areas near kauri trees, to protect them from dieback, and say the Department of Conservation’s need to cut costs is behind the use of plastic cells under paths.
A stretch of track through Okura Bush, just south of Stillwater, will be one of the first in the country to have a new track system installed that aims to reduce the spread of kauri dieback, with work scheduled to begin next month.
However, the system, known as geoweb, has met opposition from local environmentalists who say they want proof that it is as effective as building boardwalks, before it is laid.
Kauri dieback is caused by spores that infect kauri roots, and is killing large numbers of trees. It can be spread on the boots of people who walk through mud containing the spores, which is why systems that keep walkers off the mud and roots are needed.
Geoweb, which the Department of Conservation (DOC) says is cheaper to lay than boardwalk, consists of linked plastic honeycomb-shaped cells, which are filled with bark and gravel, then covered with more gravel.
DOC is rolling out the system as part of a kauri dieback protection plan that received government funding in the last budget – $10.7 million was allocated to upgrade tracks to prevent the spread of kauri dieback and $10.9 million to maintain the tracks and increase public awareness.
DOC Auckland operations manager, Keith Gell, says DOC trialled the geoweb system for seven years in Kerikeri and it’s proven to keep tracks free of mud, preventing kauri dieback spread. “The trial also proved that geoweb protects roots,” Mr Gell says. “The roots grow underneath, fully protected from the impact of people walking on the track.”
The 8km Okura track has become very popular – since 2011 the number of walkers is up from 9000 to 70,000 per year – and it also has a significant problem with kauri dieback, which is why it was among the first to be assessed by DOC. DOC’s kauri dieback team inspected the whole track and identified a stretch that gets wet and muddy and is next to kauri. Its experts decided that a 225m portion of this requires boardwalk, and a further 374m should have geoweb installed.
Friends of Okura Bush volunteers, who undertake pest control and other work within the forest, say that they were not consulted.
Chair Lezette Reid says that although they have been working with DOC on a kauri management plan for a year, the first they knew “something was up” was when they saw surveyors in the forest, early this year.
“By the time we saw the plan [for the geoweb], it was already out for tender,” Mrs Reid says.
She says that boardwalk is the proven, ‘gold standard’ used in NZ forests for decades.
“We’re told that geoweb is cheaper than boardwalks, but haven’t been able to get figures on maintenance costs for it as yet. You need to keep topping up the gravel, which compacts over time and although boardwalks also require maintenance it surely isn’t as major as helicoptering in piles of gravel?”
She says until they see evidence of geoweb’s effectiveness in protecting trees, Friends of Okura Bush would rather fundraise themselves to build boardwalks, which she admits would be a massive undertaking. “We only have remnants of native forest like this left and they’re precious. We should be spending money on them, not cost cutting.”
DOC is set to roll out the system on a big scale, after surveying a total of 735km of track in kauri forest, and Mrs Reid’s organisation is seeking that the process be put on hold.
“We want DOC to review its plans and undertake proper consultation with communities who care about their forests to avoid mistakes and the waste of taxpayers’ funds,” she says. “We acknowledge that DOC is committed to our forests, and underfunded, but if they share their problems then much better solutions will emerge.”