The deaths of hundreds of kauri struck down by a fungal disease despite attempts to thwart it has jolted officials to urgently plot a nationwide joint-action response.
Kauri in Auckland's west, including the Waitakere Ranges Regional Park, Huia, Oratia, Karekare and private land in Waimauku, have died.
Another outbreak has spread through Department of Conservation land at Pakari, on the east coast north of Auckland, and about 100 trees on that site are dead or dying.
Kauri in forests at Albany Scenic Reserve and Okura have also been hit by the disease.
Soil samples taken near the Waipoua Forest, where the country's biggest kauri, Tane Mahuta, stands, have revealed that the disease is present there too.
The Auckland and Northland regional councils, the Department of Conservation and MAF Biosecurity are working to limit the damage and find a cure for the disease.
Landcare Research is investigating where the disease has spread to, what transports it, and how to control it.
Caused by a microscopic fungus-like plant pathogen called Phytophthora taxon Agathis, or PTA, the disease lives in the soil and is believed to be transported on people's shoes or by mammals - primarily wild pigs.
The Auckland Regional Council has trained 70 of its staff to identify the disease, put up signs about it on 96 Waitakere Ranges tracks and installed shoe-cleaning disinfectant mats at the park.
The council's biosecurity manager, Jack Craw, said last night it was hoped the mats had eliminated the chance of humans spreading the disease as long as people stuck to tracks.
The regional council had also stepped up its pig control programme, hiring eight hunters to complete within two months a year's worth of work reducing pig numbers in the park.
The council had also employed two new staff to liaise with private landowners with kauri on their properties. They were available to all concerned land owners, and would give them training and sterilising products, Mr Craw said.
The council had spent $200,000 on controlling the outbreak, and more work was planned.
WHAT YOU CAN DO TO HELP
* Keep away from kauri tree roots.
* Stay on tracks.
* Scrape dirt off footwear before entering and leaving forested areas.
* Sterilise soles of shoes using trigene or bleach.
WHAT TO LOOK FOR
* Infected trees have yellowing foliage.
* The base of the trunk will have lesions, like big cuts, with white gum oozing from them.