Future tracks upgrade to help counter kauri dieback

 

BY JULIA WADE

A massive three year operation to scour three million hectares of Northern countryside for signs of a deadly tree disease has shown the majority of possible contaminated sites lie in Northland. 

A comprehensive aerial survey carried out by Ministry for Primary Industries (MPI) Kauri Dieback Programme, identified that out of the 450 Northland, Auckland and Waikato kauri sites, three-quarters requiring further investigation are individual trees growing within bush areas in Rodney district, Whangarei and southern Kaipara. 

The results leave Northland Regional Council (NRC) with an extensive task ahead as the symptoms of kauri dieback – a yellow, thinning canopy which also could be caused by drought, poor soil conditions, high winds or cattle movement – can be difficult to assess from air alone and the most reliable way to confirm the disease is with the time-consuming and expensive ‘ground-truthing programme’, where soil and data is collected from each individual tree. 

NRC’s Group Manager Environmental Services, Bruce Howse, says the council plans to work with joint-agency partners regarding available options to fast-track the ground-truthing programme as well as continue working alongside landowners. 

“Council has been providing advice and assistance for many private Northland landowners who have reported trees with kauri dieback symptoms in recent years… to develop personalised management plans to try to reduce the risk of the disease spreading from private land and district council reserves,” he says. “We want to remind landowners that legally, under the Northland Regional Pest Management Plan, any suspected kauri dieback must be reported to an appropriate management agency.”

Found mainly in the upper North Island, the fatal disease Phytophthora agathidicida effectively starves kauri of all ages to death, the microscopic fungus-like organism which lives in the soil infecting and damaging root tissues that feed the tree nutrients and water.
 
The privately-owned Benton Leslie Reserve in Settlement Road, Kaiwaka, was closed to the public last December for five years in order to protect the many 500-year-old kauri that grow in the land including an ancient 1000-year-old tree. Department of Conservation shut down access after the owner expressed concerns over the increasing threat of the disease, as the trees were unprotected from people being able to walk right up to the trunks. 

Human activity in nearby soil is one of the main ways fungal spores spread, especially when people walk on unofficial tracks or do not clean footwear after a trek. 

In respect to the Tanekaha Tracks in the Brynderwyns, Mangawhai Tracks Charitable Trust spokesperson Gordon Hosking says fortunately from the point of kauri dieback the native trees are not a common sight. 

“Only a handfull of trees, generally young rickers, are seen from the tracks and we have been careful to keep the walking areas away from them whereever possible. We believe the greatest risk of spreading the disease in the general area is feral pigs which root up the ground and carry soil on their trotters. They are quite prevalent in the area,” he says. “However we are mindful of the risk to our forest and maintain a boot treatment station at the entry point to the tracks with brushes and spray bottles of disinfectant, and plenty of signage encouraging walkers to use them.” 

DOC Senior Communications Advisor, Gabrielle Tully, says there has been an agreement to upgrade tracks before February 2019, in the Brynderwyns and Mangawhai areas including Mangawhai Walkway, Langsview Track and Mangawhai/Brynderwyn Link Track.

“These are important as they are part of the Te Araroa Trail,” she says. “The aim is to eliminate muddy sections, to protect Kauri roots and involves installing Geoweb filled with bark/aggregate mix, capped boxed steps, gravelling, boardwalks, fencing and viewing platforms. Cleaning stations and signage will be installed on all entrances to the track sections that are upgraded too.” 

An official DOC sign warns residents of a reserves closure due to the potential threat of kauri dieback.


“… we are mindful of the risk to our forest and maintain a boot treatment station at the entry point to the tracks with brushes and spray bottles of disinfectant, and plenty of signage encouraging walkers to use them.”
- Gordon Hosking, Mangawhai Tracks Charitable Trust spokesperson