Kauri seeds may be the key to fighting dieback

Rongo Bentson (Te Rarawa) at work collecting kauri cones. Photo / Supplied

One of the biggest kauri seed collections to be undertaken in decades is under way across the upper North Island, in an effort to identify trees that are resistant to kauri dieback.

The collection, from more than 500 trees, is part of the Scion-led Healthy Trees, Healthy Future (HTHF) programme focused on researching and combating several Phytophthora species, including Phytophthora agathidicida, aka kauri dieback.

Fourteen 14 iwi/hapū groups, including Omahuta, Te Roroa, Te Rarawa, Te Rawhiti, Ngati Hine, Ngati Rehia and Te Uri o Hau, are working with researchers from Scion, Manaaki Whenua — Landcare Research and professional tree climbers from BioSense to collect cones, which mature between February and April, from the Far North down to Tauranga.

The project depends upon the cones being collected while still on the tree, so the parent trees can be identified, and more can be gathered if they are found to be resistant. The cones are sent to Scion, in Rotorua, where some of the seeds are raised in a special polyhouse with strict hygiene precautions.

Seeds not used this year will go to a seed bank for iwi/hapū to use in research or restoration.

"By taking seed from mature trees, we're hoping to get a better understanding of the range of genetic resistance present. This is one part of understanding why and how some trees succumb to dieback and others remain apparently disease-free," programme leader Dr Nari Williams said.

When the seedlings are 15 months old they are sent to Landcare Research in Auckland, where they are flooded with water containing Phytophthora agathidicida to encourage infection. Researchers monitor them to see how the disease takes hold and how long they survive.

They are also analysed to see what chemical reactions are triggered, in the hope that one might neutralise the disease.

"Although early days, it's starting to get really exciting," Dr Williams said.

"The team at Landcare Research have started to see a range of responses to how the plants succumb to infection. There is a big difference between understanding what happens in the glasshouse and how vulnerable trees are within the forest, but it gives us hope for the future of kauri."

The team from BioSense is co-ordinating the collection teams, iwi engagement, cultural safety and hygiene protocols, and the shipping of the cones, ensuring that no soil, water or organic matter is transferred between sites, and that cultural safety and competency are demonstrated by all researchers at all times.

The programme will end in September but the researchers hope to continue the work in partnership with iwi/ hapu.