Kauri are some of New Zealand’s most important taonga – both ecologically and culturally. But the trees are being killed by incurable kauri dieback disease – caused by a pathogen called Phytophthora agathidicida – and the fight to save them has been slow and convoluted. Stuff senior journalist Denise Piper and visual journalist Jason Dorday investigate what is happening to save kauri while they still stand.

Many people are moved to tears when they first see Tāne Mahuta – the legendary Lord of the Forest and Aotearoa’s largest tree.

“When people see the majestic beauty of Tāne Mahuta, we quite often see people cry – they didn’t realise that there was a natural wonder like this,” said Snow Tane, Te Roroa general manager.

The tree is immortalised in Māori legend for separating his sky father, Ranginui, and earth mother, Papa-tū-ā-nuku, pushing them apart with his legs to create the world of light.

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But just kilometres away from this icon, visited by thousands each year, is another site that can bring tears to the eye: dead kauri trees which have been cut down and left to rot.

The trees were in a high kauri dieback impact area and, while some were struck by high winds, all were a danger to the state highway which runs through the forest, Tane said.

The risk of spreading kauri dieback was so great the trees have to lie where they were cut, said Tane, whose iwi is kaitiaki for Waipoua Forest, which includes Tāne Mahuta, Te Matua Ngahere (father of the forest) and hundreds of other kauri almost as large.

The 60 Te Roroa members who both live and work in the forest are constantly reducing the risk of spreading kauri dieback by following strict protocol – such as working in the least affected areas first and hunting pigs away from kauri stands.

In 2018, the fungus-like pathogen which causes kauri dieback, Phytophthora agathidicida or PA, was found less than 60m away from Tāne Mahuta.

But the iwi has since been empowered to better protect kauri, with up to 20 kauri ora workers who monitor infection rates, treat infected trees with phosphite, grow kauri seedlings and carry out monitoring for scientists.

Tāne Mahuta now has fenced boardwalks and gates for safe viewing.

The Department of Conservation has also funded kauri ambassadors who educate visitors on proper cleaning and sticking to the tracks.

While the rules and signs are pretty straight-forward to follow, Tane said they are often broken by people entering the forest to steal plants, non-compliant pig hunters who release pigs for sport and even those wanting to spread ashes of a loved one around Tāne Mahuta.

Kauri ora worker Conrad Marsh said the biggest risk in Waipoua Forest was people who came in with a lack of awareness and a lack of connection to nature itself.

“But our goal is, when someone walks in not connected and they leave connected [with nature], that’s our job,” he said.

Te Roroa has taken on another job: teaching other Tai Tokerau iwi – plus now landowners and community groups – to look after their own forests, following the proven kauri protection protocol, Tane said.

Empowering mana whenua was also an important part of Tiakina Kauri, the new kauri protection agency, said manager Alan McKenzie.

Given kauri trees could live for up to 2000 years, it made sense to involve people who took a longer world view and considered the trees a taonga, he said.

“They whakakapapa to the kauri – they’re an integral part of it.”

Mātauranga Māori (Māori knowledge) is also an integral part of the BioHeritage’s National Science Challenge for kauri dieback and myrtle rust, Ngā Rākau Taketake.

The programme brings together researchers from different institutions and disciplines – whose research was previously fragmented and ad-hoc – using Government funding, said science leader Dr Nick Waipara, from Plant & Food Research.

“The recognition around mātauranga is important. In my opinion, all knowledge is valid – it’s a desecration and an affront to assume that there’s only one source of knowledge.”

The challenges for the programme were huge given there was still no clear way to detect where Phytophthora agathidicida was present in the soil and no cure, Waipara said.

“The challenges have been laid by kaumatua: ‘Tell me when you have saved one tree.’ That’s my fundamental wero or challenge.”

Rāhui on kauri forests are one example of using mātauranga Māori and tikanga to help stop the spread of kauri dieback.

Rongoā Māori, or traditional Māori medicine, involved treatments from plants or parts of whale, applied with karakia and ihirangaranga (positive vibrations), Tane said.

Monitoring of rongoā applied to sick kauri in nearby Trounson Kauri Park had showed positive results, although the traditions had not yet been standardised in a way they could be scientifically measured, he said.

But other practices, such as using the cleansing power of kānuka in a scientific application, were showing promise, Tane said.

“There’s no silver bullet, yet. But there is hope.”

Waipara said the deadline was fast approaching for science – in all its forms – to make a last stand for kauri.

“This has to work.

“It’s limped along and been delayed and all sorts of things, but the programme and the research runs out at some time and kaumatua are still saying, ‘show me one tree you have saved’.”

This series was produced with funding from Bruce Jesson Foundation.