Sandra Coney: An insidious tragedy at our door

Kauri in the Waitakere Ranges showing signs of disease in the canopy and the trunk. Photo / Jim Eagles

A pity it had to take an Australian, Germaine Greer, to focus national attention on the unfolding tragedy of the disease that's killing our kauri. But the matter certainly does need that level of interest if we are not to end up with our once-glorious northern indigenous forest devoid of its most celebrated species.

Recent surveys by the Auckland Regional Council - which grid-searched the Waitakeres from the air and then tested samples taken from the soil around the same trees and sometime the trees themselves - showed that 11 to 13 per cent of the kauri areas in the Waitakere Ranges Regional Parkland have trees infected with PTA or phytophthora taxon agathis, a microscopic fungus-like pathogen that is spread through the movement of contaminated soil and water.

Of course, these are only the ones visible from the air because of yellowing or dead crowns. Nobody knows how many other trees are infected but not yet showing such easily detected signs.

When you map the known areas of infection you can see that the disease is spreading along walking tracks and routes used for pest control. Almost 70 per cent of diseased areas correlate to the track network.

High-use tracks, such as Auckland City Walk, are more likely to be diseased than others.

The disease has now been found in the soil on walking shoes and in the debris in grates under equipment installed to clean people's shoes. Waitakere tracks frequently go through kauri areas with walkers actually treading on exposed roots. Once a tree is infected it can pass it to neighbouring trees. Other factors such as feral pigs may exist - and culling efforts have been increased - but humans are by far the biggest threat.

The dilemma here is how to protect the trees from walkers. Options are boardwalks, re-routing and improved track drainage. Some of this has been done, but, given the 270km of tracks in the Waitakeres, it is a large and costly task and the remedial work could spread the disease.

Some track closures during the wet season have been applied for the past two years. More than 105 hygiene stations have been placed at track entrances and junctions, but hidden cameras have shown about half of visitors ignore them. In any case, when tracks stretch for kilometres, you would have to have multiple hygiene stations to prevent spread and people would not comply.

The other main area of kauri in the Auckland region - Hunua Regional Park - has no kauri disease and the council needs to keep it that way.

Greer proposes closing the Hunuas and that should be talked about. The Auckland Council is right now working on whether clean areas in the Waitakeres should be quarantined or closed to the public. Should an area of magnificent mature unaffected kauri like Robinson Ridge in the Cascades be closed to prevent the disease spreading and thus preserve a reservoir of healthy kauri for the future?

There are signs that measures such as quarantining and closures may be difficult. The scale and consequences of the disaster have not sunk in.

An environmental disaster such as the grounding of the Rena grabbed headlines and led to calls for more to be done, more quickly, but the quiet insidious tragedy on Auckland's doorstep has not captured public attention in the same way.

As well, Aucklanders are demanding higher impact and adventure sport activities in natural wilderness areas.

There is already canyoning in the Waitakeres and it has become popular to run the Waitakeres. Mountain bikers have lobbied for years to get into the Waitakeres, despite the unsuitability of the terrain and the damage they could cause.

There are ambitions to try to bring more people to the Waitakeres, which is the last thing that is needed right now.

Ex-mayor of Waitakere, Bob Harvey, is lobbying hard to get commercial concessions and international promotion for tourism of the Hillary Trail. In this matter he has found a sympathetic ear in Mayor Len Brown.

Harvey is lobbying for "Great Walk" status for the Hillary Trail which would involve track widening to around 2m, surely a foolhardy idea with risks to the health of the forest through spread of disease and creating breaches in the canopy of the forest.

Even within the council itself, there are contradictory policies at work. Despite the spread of the kauri disease - the number of new epicentres in the parkland and on private property - the council knocked back bids from biosecurity staff for more funds in the proposed budget for the next financial year.

Tourism is high on the agenda in the Auckland Plan and is seen as the means to kick-start Auckland's economic revival, yet you will hardly find a mention of the kauri disease in the plan.

In December, the council's Auckland Tourism, Events and Economic Development presented a new Auckland Visitor Plan, promoting developments curiously like that being proposed by Bob Harvey.

Ateed described the Waitakeres as under-used without being able to present any evidence to support that.

It proposed a "canopy walk" and Great Walk in either the Waitakere Ranges or the Hunuas, proposals that would increase the risk of disease spreading.

As Germaine Greer's comments show, there is international recognition of the environmental disaster unfolding on Auckland's doorstep, but less awareness at home.

Aucklanders will have to think hard about whether they want to, in Bob Harvey's famous words, "love the Waitakeres to death" or bite the bullet for the sake of the survival of our region's most majestic and ancient tree.

Sandra Coney is a Waitakere councillor on the Auckland Council and chairwoman of its parks, recreation and heritage forum. The dilemma here is how to protect the trees from walkers.

Read the Listener's article by Germaine Greer here.