Editorial: We must find the cause of kauri dieback

The Auckland Council has taken its time to close most of the walking tracks in the Waitakere Ranges in an effort to save kauri from the dieback disease. In February it proposed to do so and invited public views on the proposal. This week it decided to go ahead and the park will be largely closed by May 1.

Many will wonder what took them so long, and cynics might suggest they timed the closure for the change of seasons, If so their timing was perfect. The turn in the weather this week makes a weekend tramp in the Waitakeres a less inviting prospect.

It is hard to see why they ever put the proposal out for public comment. Since science seems not to know what is causing the dieback and how to cure it, nobody can offer an informed view on what should be done.

If there is good reason to suspect the disease has been spread by human feet it makes sense to close the tracks. That could stop the dieback spreading to all kauri in the Waitakeres and to other bush parks in the region that offer good walks. If the disease was also being spread by wind or birds it would probably have appeared in all of the region's parks by now.

In the 10 years since the dieback was noticed it has become rife in the Waitakeres and the nearby Awhitu Peninsula and some patches of bush in the Rodney ward, all on the west side of the region. Kauri in bush reserves on the eastern side, the North Shore, Waiheke and the Hunua Ranges, appear to be blessedly free of the disease so far.

The must be a mystery to those convinced that humans are the vector because serious bush walking does not have wide popular appeal. Chances are, those who enjoy it have tramped in kauri forest on both sides of the region.

They are also people who would have been using the hygiene stations the council has provided in its previous attempts to contain the disease.

The council received 800 written responses to its proposal to close all but a few tracks in the Waitakeres, 43 per cent thought the council was going too far and the rest were about evenly split between those who would have preferred to see more tracks closed and those who think its proposal is about right.

Since those who were interested enough to make a submission are probably all keen users of the park, the council needs to note that nearly half of them do not support the lengths to which it is going. It needs to show those people the tracks will not be kept closed without good reason.

That means, its park managers need to strongly enforce the ban and carefully monitor its effect, if any, on the disease. If they have been following its spread year by year they ought to be able to tell a year from now whether the absence of trampers is making a difference.

If it is not making a difference, they need to find another solution. But even if it is making a difference, and the park is to remain closed, they need to continue the quest to understand this disease and find an antidote.

For it is unthinkable that the beautiful regenerating kauri forest on the Auckland's western hills will be forever off limits to those who love it.