Plant pathogen Phytophthora, Greek for "destroyer of plants", is threatening to finish the work the axe started.
In the North, in remnant forest that escaped the blade, centuries-old kauri are being laid low in a "dieback" caused by the disease.
Effective solutions have evaded Western science to date, but that doesn’t mean they are not out there.
Indeed, they might lie close to the roots of the stricken kauri themselves.
That’s certainly the belief of environmental sociologist Melanie Mark-Shadbolt, champion of matauranga Maori. When the disease was first identified on the New Zealand mainland, more than a decade ago, Maori immediately knew where the answer would be found, she says.
"We know which plants co-habitate, so we know which plants are the brothers and sisters of the kauri and we know which plants should be around them protecting their roots. And protecting them from infection."
It’s an understanding that received little attention during early efforts to meet the new challenge, but more recently Dr Monica Gerth, at Victoria University, has worked with Maori knowledge holders looking at medicinal plants. They recently published a paper.
"They have found a native plant that kills the phytophthera in the soil, so it is a potential solution now," Mark-Shadbolt says.
There’s a chance Dr Gerth, an American, could have got there herself, waded into the forests of Te Taitokerau and emerged some years later with an inkling.
"She would have had to look at a thousand plants and it would have taken her 10 years," Mark-Shadbolt suggests.
"But because she worked with knowledge holders, they narrowed it down instantly for her. They said ‘don’t even consider these plants, because they don’t co-habitate with kauri’, ‘don’t consider these plants because their medicinal properties aren’t strong enough’, ‘here are the 10 plants to consider’. And in fact, we will even go harvest them because we know where the best ones are.
"When it is coupled together — traditional knowledge and Western science — it becomes a really powerful tool for speeding up the process."
"If you have big gnarly problems, like climate change, that are escalating really rapidly, then you need to be as open as possible to all knowledges that could speed up the process, help you find solutions much faster," she says.
A point of clarification is probably required here. We should not, Mark-Shadbolt says, fall into the trap of thinking about matauranga as exclusively ancient knowledge.
"That is not what Maori mean when they say matauranga — they mean all knowledge. So they mean knowledge that is traditional, it could be from pre-Aotearoa but it can also be knowledge right now, or future knowledge. So matauranga is a very time-free concept that includes everything that Maori work in and understand."
Melanie Mark-Shadbolt is well schooled in Western knowledge traditions. She’s kaihautu chief Maori adviser at the Ministry for the Environment, the director Maori of the Biological Heritage National Science Challenge, the Maori research manager-kaiarahi for the Bio-Protection Research Centre based at Lincoln University, and is a founding member of environmental not-for-profit Te Tira Whakamataki — the Maori Biosecurity Network. Her whakapapa includes Ngati Porou, Te Aitanga-a-Hauiti, Ngati Kahungunu, Te Arawa, Te Atiawa, and Ngati Raukawa.
In all those roles she’s a champion of matauranga Maori, or indigenous knowledge. The example of the kauri and others she talks about — the way Maori are bringing insights to the problem of myrtle rust, or Tuhoe are finding native toxins in their rohe as an alternative to 1080 — capture some of that. But it’s also more fundamental, more than a different viewpoint on a shared problem.
She points to another piece of research — carried out in a Western institution — that gets a little closer to what matauranga Maori encompasses.
This one’s from the University of British Columbia, in Canada. Last year, a study led by researchers at the university looked at land areas in Australia, Brazil and Canada and found that the total numbers of birds, mammals, amphibians and reptiles were the highest on lands managed or co-managed by indigenous communities. There was more life than in national parks.
"This suggests that it’s the land-management practices of many indigenous communities that are keeping species numbers high," lead author Richard Schuster said.
"Going forward, collaborating with indigenous land stewards will likely be essential in ensuring that species survive and thrive."
Understanding why that might be involves stepping back from the way in which such issues — preservation of biodiversity and the response to extinction threats — are typically approached.
That usually happens, Mark-Shadbolt says, within the conventional Western world-view of humans as separate from the environment. Which is quite different from a Maori world-view.
"At the very core an indigenous world-view is about environment first, if we simplify it, with humans being a part of it," she says.
"A non-indigenous view is that humans have — it comes from Christianity — domain over the world and everything is here as a resource for us to utilise.
"So there are some times when those two world-views can’t align.
"That’s a simplification of it of course, because societies change and evolve and adopt other perspectives, but as a simplification that’s kind of where the two world-views arise."
"Climate change is one of those issues that is an ecosystem issue. Everything is affecting the other and you can’t divorce one from the other."
In looking for a solution to such a chaotic problem, you need a knowledge set that is used to thinking about interdependencies and sees the world in terms of interwoven connections.
"I guess that’s why there is this interest, all of a sudden, in what indigenous knowledge can offer in environmental solutions. That’s worldwide, not only here. I guess here we’re lucky that there have been policies in place that encourage it."
That work dates back at least as far as the Government’s Vision Matauranga policy, coined in 2005. It aims "to envision knowledge, to think about new ways of doing things, to find answers, to solve problems".
Critical to that process is valuing and caring for the knowledge holders, the country’s kaumatua.
That’s a focus of the National Science Challenge with which Mark-Shadbolt is working.
Overseen by the Cawthron Institute’s Dr James Ataria, it involves an examination of "matauranga Maori characterisation of biodiversity": how Maori characterise our flora and fauna.
We understand how taxonomy approaches it but how do Maori?
It’s a knowledge that’s passed on, Mark-Shadbolt explains, so kaumatua will know how one tree relates to another, and can characterise plants in terms of their uses.
The research inevitably shifted from a narrow focus on the way in which kaumatua’s knowledge operated vis-a-vis their environment, to looking at a bigger picture of wellbeing that tied in the environment, the kaumatua and the language linking them.
For example, kaumatua were concerned about issues of succession, given the small number of traditional knowledge holders left in the Maori world, those most intimately connected. So the project has become both about how to protect biodiversity knowledge and pass it on, and how to keep those knowledge holders well. It has connected knowledge and personal wellbeing with wellbeing of the forests.
Further, as te reo Maori is the vehicle by which those connections are expressed, the project has highlighted areas there that need attention.
One kaumatua was concerned about loss of dialect as young Maori picked up a more generic reo at university, Mark-Shadbolt says. As that generic tongue took over, meanings slipped away.
"He was saying, for example, what might be called a kereru in the South Island is not called a kereru in certain parts of the North Island, and we are losing that because we are just teaching standard language. That’s really important because their culture and their wellbeing is connected to understanding that language."
At first glance it can seem a relatively unimportant consideration. The pigeon continues to wear a Maori cloak. But that is to miss some of the matauranga around the reo.
"A lot of tribes believe that te reo Maori comes from the language of the birds," Mark-Shadbolt says.
"We learned to speak by mimicking birds, as humans. That’s why so much of our language sounds like birds. A lot of their names sound like they sound. A kiwi sounds like a kiwi. A tui is the sound it makes. Other tribes, like Te Arawa, mimic birds on the marae. People are taught to speak like birds, or they adopt a personality like a bird when they speak.
"There are all these connections between our environment, our trees and our people that we were losing, which meant we were losing the knowledge. But equally, they saw a connection between that and environmental degradation. So when you lose that connection, understanding why that bird is important to you, or why that tree is important to you, you lose the desire or the ability to protect it."
The plight of the kauri embodies that dynamic.
Mark-Shadbolt says when you consider the progression of kauri dieback, conversations soon turn to the relative health of certain tribes and how that is reflected in their forests.
"Where a community is really strong in their reo or strong in their tikanga, their practices and their prayers and their songs, then their forests remain strong and healthy, because they have that strong institutional memory. They have that whakapapa memory of how to protect those forests."
A good example of that is embodied by one of the members of the Biological Heritage National Science Challenge, Mark-Shadbolt says.
Kevin Prime, of Ngati Hine, Ngati Whatua, Tainui and Welsh descent, an Environment Court commissioner and Conservationist of the Decade in the 1990s, is project kaumatua.
"He has always argued that his forests, in Ngati Hine, Motatau, in Northland, are kauri dieback free because of the strength of his karakia, his prayers. When we first start talking about that, when we first start mooting that in the science space, people joke a bit, and go ‘whatever’.
"Obviously for Maori, they go, ‘oh, yeah, that makes sense’. It makes sense that your prayers are so strong that it keeps the dieback away."
Now, you can either (a) accept it or (b) start to think about what else it might mean and how to test it from a scientific perspective.
Mark-Shadbolt says she is in the (a) camp.
"I just accept it because he says it is true."
But there is some really interesting research around coral reefs and sounds, she says. When speakers were placed in dying coral reefs to play the sounds of healthy reefs, fish returned, bringing nutrients that could play a role in reviving them.
"So the sound that a healthy coral reef made, when played in the space of a sick coral reef, had healing properties.
"I guess in one way that’s a really good analogy for what Maori are trying to say when they say karakia can help protect our kauri forests. Because our karakia, our prayers, our moteatea, our chants, our waiata, our songs, all of those have frequencies and tones and rhythms to them that potentially mimic the sounds of healthy forests and healthy birds."
The research begins to weave strands of matauranga Maori and Western science. In the former tradition, Prime’s karakia are obviously powerful, he’s a powerful tohunga, knowledge holder and kaumatua. But the question that follows from the latter tradition is whether there is something in the sounds and the vibrations of his karakia — because he has held on to his knowledge — that mimics the sound of a healthy forest.
And it highlights a point Mark-Shadbolt made earlier, about environments managed by indigenous people doing better.
"One of the best ways we know of for protecting our biodiversity and restoring it is to bring humans back into the environment," she says.
"That might mean that we have to let people back into those forests and have people living in there."
You look after your backyard, she says.