Dying kauri trees
Image: Ministry of Primary Industries | ©

Introduction

PA is a disease that can kill kauri of all ages. It is also referred to as kauri disease or kauri dieback.

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PA - a threat to kauri

Phytophthora agathidicida (PA) is a fungus-type pathogen which damages the tree’s root system. It reduces the tree’s ability to take water and nutrients from the soil and transport it throughout the plant. This is sometimes referred to as kauri disease or kauri dieback.

PA could have devastating effects on New Zealand’s kauri forests. It has been found in Northland, Great Barrier Island and the Coromandel Peninsula.

There is no known cure, but we can help reduce its spread by avoiding any movement of soil around the roots of trees. That means making sure we stick to the tracks and have spotlessly clean footwear and any gear that might touch the ground.

The disease is caused by a microscopic fungus-like organism, called Phytophthora agathidicida (PA). It lives in the soil and infects kauri roots, damaging the tissues that carry nutrients and water within the tree, effectively starving it to death.

How we are managing kauri dieback

There’s currently no proven cure or treatment and nearly all infected kauri die. The disease is easily spread through soil movements, for example, when soil is carried on dirty footwear, animals, equipment and vehicles. We can save our kauri forests by containing the disease and stopping it spreading to other areas. Kauri dieback is found in the upper North Island. 

How you can help

Kauri dieback can be spread by just a pinhead of soil. But you can help save kauri.

  • Clean soil off your footwear and other gear every time you enter or leave an area with native trees, and at every cleaning station.
  • Use disinfectant only after you've removed all soil.
  • Stay on track and off kauri roots. A kauri’s roots can grow outwards 3 times as far as its branches.
  • Spread the word within your networks on how to stop kauri dieback.

Infected trees may not show it – always assume there is kauri dieback. If you're in native bush in the upper North Island, it's likely you'll be near kauri.

Why it matters

Kauri forests once covered 1.2 million ha from the far north of Northland to Te Kauri, near Kawhia and were common when the first people arrived around 1,000 years ago.

Significant kauri, like Tane Mahuta and Te Matua Ngahere, are more than just trees. They are a presence that connect us with the past, and with those who have gazed up at them over hundreds of years.

Kauri create shelter and nourishment for other species, and are important to the indigenous forests of the upper North Island. A number of plants are found only, or mostly, in association with kauri. When kauri disappear, the kauri forest goes too. 

Kauri are a taonga species for Māori and have significant value for our ecosystem, historic heritage, cultural values, tourism industry, and national identity.

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