Kauri dieback is rampant in the Waitakere Ranges, new study shows

Monday, 19 December 2016

A dying kauri on the Maungaroa Ridge Track in the Waitakere Ranges regional park above Piha.

The number of trees infected with kauri dieback in the Waitakere Ranges has nearly tripled in five years.

The regional park in west Auckland is now the most heavily diseased place in the country, with more than half its substantial kauri areas showing symptoms of the incurable disease.

Gummosis on the trunk is one of the symptoms of kauri dieback disease.

Auckland Council revealed the shocking statistics in a press release on December 19.

Its forest health survey, soon to be released, shows that 19 per cent of kauri in the popular regional park are sick – up from the 7 per cent that showed signs of the disease in 2011.

The study found the disease is more prevalent in places where there is more foot traffic.

A dead kauri in Cascades Kauri park in Auckland's Waitakere Ranges.

* Kauri dieback study to track disease in the Waitakere Ranges**

The infestation is greatest in areas with the highest foot traffic, including where intensive pest control is carried out.

This tree in Cascade Kauri park in the Waitakere Ranges is sick, with a thinning canopy and gum bleeding from its trunk. Six years ago 'Agatha' appeared healthy.

Penny Hulse is a councillor for Waitakere and chairperson of the council's new Environment and Community committee.

In the release she says the study's results are alarming and urgent action is required to give the city's kauri forests a chance of survival.

'A disappointing 83 per cent of park visitors are walking past cleaning stations without scrubbing their shoes with trigene, going off-track or disregarding closed tracks,' she says.

'It is time for all Aucklanders and visitors to our kauri forests to take greater accountability for their role in preventing the spread of this disease that is threatening the future of our kauri taonga.

'The council is stepping up its efforts. I'm calling on everyone else to play their part too.'

The five-year forest health survey was due out in August but was delayed and is now being peer-reviewed before release early in 2017.

Only a summary of the results of the study has been released, which uses helicopters, site inspections and soil samples as well as GIS mapping to update kauri dieback maps.

The council says that until a cure is found it is concentrating on restricting the disease from spreading.

More than 10 per cent of the 279 kilometres of walking tracks in the Waitakere Ranges has already been closed in order to create kauri protection zones.

The new survey shows that 83km of the tracks go through infected areas.

In the release, Waitakere Ranges Local Board chairman Greg Presland calls for more investment to stop the disease spreading and also for the public to ensure it is playing its part.

'We now urge locals to talk to their friends, families and visitors, make sure they always walk the talk when out there in the ranges, and help us shift compliance with protection measures towards 100 per cent,' he says.

Kauri dieback disease is a form of Phytophthora or PTA, and given the full name Phytophthora agathidicida this May.

It is a microscopic fungus-like organism which has spores that can spread when soil, water and wood is moved around.

The council says that most of Auckland is free of kauri-dieback disease – including the Hunua Ranges, south-eastern and northern Auckland and most of the islands of the Hauraki Gulf.

But there are infected kauri on private properties, as well as in some western parks, parts of the Awhitu peninsula, and Department of Conservation reserves at Pakiri, Logue's Bush, Albany and Okura Bush.