Sam Judd: Come on Kauri, come back

Our iconic kings of the forest, the Kauri trees, are under an immediate threat of extinction.

Theses trees are so huge that they support their own unique ecosystem of epiphytes (plants that essentially hitch-hike on other plants) at the canopy. Our biggest specimen, Tane Mahuta (Lord of the Forest), which can be found in the Waipoua Forest near Hokiangi in Northland is a staggering 51.2 metres high with a girth of 13.7 metres.

At an estimated 1,250 - 2,500 years old and the biggest conifer in the world, this tree was growing here before humans ever saw the land.

Timber too good for its own good

These forest giants demise began with Maori, who burned upwards of 40 percent of New Zealand's forests to make land easier to travel across, for food cropping and so that they could harvest the new wild growth of ferns that would sprout after the destructive blazes.

Maori also selectively felled Kauri trees for buildings, weapons and traditional carving.

Then when European immigrants realised out how hard and rot-resistant their timber is. They also worked out how valuable the gum was for varnish and for the second half of the 19th century, it was Auckland's main export product, sustaining the early growth of the metropolis. Forestry became a lucrative business that and hundreds of thousands of trees were felled from the Bay of Plenty north.

With such a history of exploitation, it is a wonder that we have a handful of these majestic trees still standing today, but they too are under threat and we need to take action immediately.

Plague brings down giants

Kauri Dieback Disease (Phytophthora taxon Agathis or PTA) is a fungus-like disease that is spread through microscopic spores that get into the trees' root system and damages their tissue.

Nearly all trees infected die and thousands of them have perished since the disease was first discovered.

The disease is spread through people and animals transmitting PTA spores mainly on their feet.

Before we go blaming the high numbers of tourists that flock to our shores to experience our beautiful forests, it is actually local people causing the problem: In the Waitakeres a survey found compliance rates for the all-important washing stations was below 40% and that tourists were not to blame.

Last year, Iwi and the Department of Conservation nearly went so far as to ban people from visiting the tree to protect it from disease.

What can we do about it?

Fortunately we can have an impact on this at a personal level:

* Anyone going into the bush whether on or off track, should thoroughly clean their boots, gear, clothes and dog's feet before and after each visit.

* We must also spread awareness of the problem and explain how we can prevent the spread of this disease to others. This can be as simple as sharing this article online, or emailing the link to the Kauri Dieback information site www.kauridieback.co.nz around your contacts.

* If you are out there and see anyone failing to comply by washing his or her boots, then a polite tap on the shoulder with an explanation will no doubt help.

* For more information, or to report any suspected diseased Kauri on public or private land, phone the Kauri Dieback Hotline on 0800 NZ KAURI (0800 69 52874) or send an email to kauridieback@mpi.govt.nz