Kauri dieback (Phytophthora agathidicida, or PA) is a soil-borne pathogen that kills kauri trees. There's no cure. The science continues to evolve but the basic facts haven't changed in years: it spreads via contaminated soil and water, infected trees die, and prevention is the only management.
If you have kauri on your property, or within about 50 metres of it, here's what you need to be doing.
Recognise the symptoms
Early signs: bleeding lesions on the lower trunk (resin oozing from cracks), yellowing leaves, thinning canopy. Late signs: extensive canopy dieback, dead foliage retained on the tree, and ultimately whole-tree death.
If you suspect kauri dieback, do not sample or take material from the tree yourself. Call MPI (0800 80 99 66) or Tiakina Kauri to arrange formal sampling.
The rules: what you can and can't do
Most regions with kauri populations now have strict rules administered by Tiakina Kauri (formerly the Kauri Protection Programme) and local councils:
- No work within the kauri root zone (typically 3× the radius of the crown) without a kauri dieback plan.
- No soil movement in or out of the root zone without cleaning protocols.
- All operators working in kauri root zones must complete kauri-protection training and use approved hygiene protocols.
- Removal of kauri is heavily restricted, kauri are protected under most District Plans regardless of age or condition.
What this means for property owners
If you're building, paving, fencing or doing significant landscaping anywhere near a kauri, you need:
- A site-specific kauri dieback management plan.
- A trained operator overseeing the work.
- Hygiene stations for vehicles, machinery and foot traffic entering the root zone.
- Possibly resource consent depending on the council.
Yes, this adds cost. The alternative is killing a 200+ year old tree.
Tree work around healthy kauri
Even routine arboriculture near a healthy kauri needs care:
- All tools, boots, vehicles cleaned and treated with Sterigene or equivalent before and after.
- No movement of mulch, soil or wood out of the area without quarantine.
- Climbers approved for kauri work where canopy access is needed.
- Detailed work records kept.
If you suspect dieback
- Don't touch the tree.
- Photograph from a distance.
- Note the GPS location.
- Call MPI on 0800 80 99 66 to report.
- An accredited sampler will attend and take material formally.
Replanting where dieback has killed
Kauri dieback survives in soil for years. Replanting kauri into infected ground is not currently recommended. Replace with other natives, totara, rimu, kahikatea, that are not affected by PA.