Saving giants using Citizen Science

Fighting Kauri Dieback Disease

Next week (9 February 2017) sees the launch of a new Citizen Science project which aims to protect one of New Zealand’s iconic, native trees from a plant disease which threatens to decimate their numbers.


A healthy kauri tree
Kauri tree – © Kauri Rescue


When the first settlers arrived in New Zealand, around 1,000 years ago, the kauri tree was a common site. Kauri forests were estimated to cover over 1.2 million hectares. Unfortunately, the settlers saw the value in using its timber for ship and house building. Through harvesting the trees for timber and to make way for farmland, they reduced the forests to a fraction of their size by the mid-20th Century.

Then, in the mid-1970s, kauri trees started dying in large numbers as a result of a kauri dieback disease. The disease, which is deadly to trees of all ages, is caused by a water mould (Phytophthora ‘taxon Agathis’ [PTA]) which lives in the soil and infects the kauri’s roots. Once infected the trees, which have no resistance to PTA, die.

PTA is spread through the transfer of soil on human footwear, by animals and by dirty vehicles and equipment. In the absence of a vaccine, controlling such movement is the best way to stop the disease.

Action through Citizen Science

The new project has been made possible by a successful application for funding from the Government’s Biological Heritage National Science Challenge (New Zealand) secured by a team comprising of scientists, social scientists, Iwi (social units in Māori society) and community groups.

The project, Kauri Rescue, otherwise known as the Community Control of Kauri Dieback: Tiaki mō Kauri, will use a new citizen science tool to engage the public in the fight against the Kauri Dieback Disease. The intention is to try a new treatment using a chemical called phosphite which has, in recent trials, shown some successful results in the treatment of trees affected by PTA.

Infected kauri tree – © Kauri Rescue

An initial pilot study, involving a small number of private land owners, will be used to test and refine the methodology. Following this, the project will be opened up to a larger group of land owners who will work with scientist to treat trees on their land. The participants will also be urged to test other treatment techniques, encouraging both western science and mātauranga Māori methods.

The project team will be rigorously monitoring the results and collecting data on all treatments. The outcome will be the identification of the most efficient way of tackling PTA and helping the kauri forests to recover.

Project Team Leader Dr Ian Horner of Plant & Food Research is delighted at the opportunity to take his research to the next level and engage the public in actively developing the treatment tools themselves.

“We hope that people will find this opportunity empowering and a positive step forward in the fight against Kauri Dieback Disease. Working together to develop and test these tools and feeding results into a wider research pool will accelerate development of robust methods.  Thus, in the near future we could have effective treatments that the public can apply themselves and support others in their community to treat their own trees” he said.

The Kauri Rescue team is currently running a survey in affected areas to gauge public opinion about the effect of the disease and existing control efforts. The Citizen Science project will be formally launched next week and will initially run for two years.


Te Matua Ngahere, with a girth just over 16 metres (52ft.). The tree’s Maori name means “Father of the Forest” – Dan Nelson under CC license


Kauri trees are giants of the forest and are long-lived. One tree, named ‘Tane Mahuta’ (Māori for ‘Lord of the Forest’) is thought to be between 1,250 and 2,500 years old. It is found in the 9,105 hectare Waipoua Sanctuary, which was established in 1952 as a refuge for the kauri trees and other threatened wildlife. It would be a travesty if ‘Tane Mahuta’ and its kin were to succumb to this devastating disease. The kauri’s future depends on this project and the Citizen Science volunteers.

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