National Geographic has launched a new online feature called My Town, website like this in which contributing writers and photographers talk about their home towns, order cities, villages, hamlets, hobbit holes. . . .
I’m up this week with a piece entitled “Welcome to my wild,” which looks at the wild side of Auckland city, my home for 50-odd years. (Or should that be 50 odd years?)
I wrote the column at roughly the same time I was working on an assignment for New Zealand Geographic on the current state and future prospects of New Zealand’s native forests. As part of my research for that story I climbed some magnificent kauri trees in the Waitakere Ranges, on the western edge of Auckland city.
Kauri are one of the biological and cultural signatures of the northern part of New Zealand. Some trees are believed to be more than a thousand years old, and have been given Maori names, including Tane Mahuta, lord of the forest, and Te Matua Ngahere, father of the forest.
But in recent years kauri have been afflicted by a disease called dieback. Dieback by name, dieback by impact—the foliage turns yellow, the bark falls off the trunk and white resin bleeds from the base of the tree.
Last year I gave a radio broadcast on the problem, while perched in the crown of a kauri tree in the Waitakere Ranges. Click here to listen to the podcast.
Here’s a quick run-down on dieback:
The official name of the pathogen that causes the disease is PTA = Phytophthera taxon Agathis = “the plant destroyer that kills kauri.” Phytophtheras are part of a group of microorganisms called chromists, which lie somewhere between a fungus and an alga in the world of bugs. There are thought to be more than 500 species of phytophthera around the world, of which 116 have been described by scientists. It was a species of phytophthera that was responsible for the Irish potato famine. Another type causes a disease called Sudden Oak Death. Phytophtheras cause blights in tomatoes and avocados as well. They have been described as biological bulldozers, in that once they get established they is almost unstoppable.
PTA is a fast killer. It can kill a kauri seedling within weeks. In mature trees it can be difficult to tell how seriously the tree has been infected. The normal defence of a kauri to any kind of microbial attack is to produce copious amounts of resin, but this doesn’t work with PTA because the disease attacks the root system, stopping nutrients and water getting up the tissues of the trunk to the canopy.
Phytophtheras reproduce by producing spores, which can stay viable in the soil on a for months or even years. Much of the effort to stop the spread of PTA—spearheaded by a group called Keep Kauri Standing— targets hikers using trails in kauri forests. Specifically, getting them to clean mud off their boots and spray the soles with disinfectant. Anyone who visits a forest where PTA is present could become a vector for the disease.
Also involved in its spread are animals (cows, feral pigs and deer), forestry machinery, mountain bikes, trail bikes, and—an underestimated threat in some areas—cannabis cultivators!
The link with people has been clearly shown: almost 70 per cent of infected kauri stands are within 50 metres of tramping tracks. Also problematic is that PTA produces two types of spores, one of which can swim in waterways to a new site. As soon as it comes into contact with the roots of a kauri, the infection begins.
There is no specific cure for PTA. However, injecting trees with phosphorous acid shows some promise in containing the spread of the disease.
Kauri have been around since the age of dinosaurs, yet settlers logged between 97 and 99 per cent of all mature kauri in less than 100 years of arriving in this country. With only a remnant remaining, it is crucial that PTA be contained. Should kauri succumb en masse, the cultural and ecological loss will be incalculable.
Here are some images of kauri from the Waitakere Ranges and from an important kauri sanctuary in Waipoua, Northland. The more I see of these trees, the more I feel I have a stake in their survival. As I say in the National Geographic story, “Ko te kauri ko au, ko au ko te kauri.” The kauri is me and I am the kauri.
Kia toitu he kauri. Keep kauri standing.
At last year’s World Parks Congress—a gathering of the “protected areas community” held every ten years under the auspices of the International Union for the Conservation of Nature—there was much talk about the need to recognise the economic contribution of parks and other protected areas.
One of the clearest advocates for an economic transformation in which natural capital is recognised and explicitly valued was Achim Steiner, executive director of the United Nations Environment Programme and under-secretary-general of the UN.
“We need to bring into the treasuries and ministries of finance and the systems of rational accounting a much better appreciation of the value that protected areas deliver,” he told congress delegates in Sydney. As competition for resources and public finance intensifies, societies will not invest in nature protection without an economic justification, he said.
Traditional markets have a role to play, says Steiner. Although markets have historically treated the environment as a limitless (and therefore unpriced) good, they are an essential mechanism for restoring nature “to its rightful place at the centre of well-being, which is the ultimate purpose of the economy.” By giving due weight to the economic performance of natural capital, markets can undergird, rather than undermine, nature protection.
Indeed, until the environment’s economic contributions are included in national and corporate balance sheets, he says, a true accounting will not occur. “Conventional measurements of both macro- and microeconomic performance—GDP and corporate profit respectively—are substantially wrong because externalities are not accounted for, and they will continue to be wrong until the valuing of economic activities also includes their impacts, and the assessment of profits also value the negative externalities of business. In short, you cannot manage what you do not measure.”
In the midst of such commentary on the economics of nature, Steiner made a surprising comment. “I believe that the entire Planet Earth is a sacred site; one that sustains life, prosperity, civilization and spiritual values.”
In conversation with Steiner, I asked him how he reconciled such incommensurate values as sacredness with the metrics of economic markets. Here are some edited excerpts from that discussion . . .