Tests on a kauri tree in Chelsea Estate Heritage Park on Auckland’s North Shore have shown that it does not have kauri dieback disease.
The track where the tree is located has been closed as a precautionary measure since May while an investigation was carried out.
Another disease identified
Auckland Council Biosecurity Manager Phil Brown says that, while the tree does not have kauri dieback disease, another related disease has been identified.
“The results have shown that Phytophthora cinnamomi is present. This disease is widespread across the Auckland region, and affects a wide range of host species. It presents similar symptoms and also affects kauri but is less likely to kill a tree than kauri dieback disease,” he says.
Phytophthora cinnamomi is mainly a danger to trees affected by soil compaction, root damage, low nutrients or waterlogging. Without these triggers, trees with good root health can survive the pathogen.
Kauri dieback, on the other hand, is an aggressive primary pathogen, which can infect and kill kauri at all life stages.
Like kauri dieback disease, Phytophthora cinnnamomi is also spread via soil movement, so following the same procedures when visiting kauri areas will help prevent the spread of both diseases.
“While it is good news that kauri dieback disease itself has not been detected, we do know that the disease has a long incubation period, so we may retest the soil again in the next few months,” says Mr Brown.
Track to remain closed as precaution
The track will remain closed at least until a wider strategy across other tracks near kauri forest is agreed to by Kaipātiki Local Board. The proposed strategy is being developed now and will be presented to the board in coming months.
The tree in question was identified during the council’s track surveys that have been carried out across the north of the Auckland region. These have followed aerial surveys across the north of the Auckland region by the council with the Ministry for Primary Industries.
Mr Brown says the finding reinforces the importance of the survey programme.
“We have been able to identify the decline of this tree, test it and will continue to monitor its health,” he says.
“It also demonstrates the complexity of decision-making in terms of park and track closures to protect kauri. Not every dying kauri tree has kauri dieback, but kauri dieback isn’t the only threat to kauri health. We have also been disappointed that some people have continued to push past the barriers closing this track, putting the forest at risk,” he says.
Council working to protect kauri
Auckland Council is working to finalise a strategic framework for consistent, evidence-based decision making for kauri management across the region’s local parks. This includes work to identify alternative locations so that the impact on the recreation activities of Aucklanders is minimised as far as possible.
While regional parks represent larger areas of kauri, there are also kauri forests of significant ecological value within local parks that are currently thought to be disease free.
“In the coming months we will be providing advice to local boards about kauri in their areas, as they are the decision-makers for local parks,” says Mr Brown.
Careful management needed
Kaipātiki Local Board Chair John Gillon says a negative result for kauri dieback is pleasing. But he says careful management of kauri forest is a priority for the board.
“While it is good to hear that this tree hasn’t shown evidence of kauri dieback, it is a real concern for us to hear that phytopthora cinnamomi is present.
“This reinforces the vulnerability of our kauri trees and heightens the need to have a good management plan in place. We’ll be working with our parks and biosecurity experts to protect our Kaipātiki kauri as a matter of priority.
“In the meantime, we hope locals will continue to respect the closure in place in Chelsea Heritage Park and, if they’re visiting kauri forest anywhere in the region, follow all hygiene measures in place so that the disease doesn’t get brought back to our local parks,” says Gillon.
Natural environment targeted rate will help kauri
North Shore Ward Councillor Richard Hills says the recently confirmed natural environment targeted rate will accelerate the work of the kauri dieback programme across Auckland.
“As a result of Aucklanders supporting this targeted rate, kauri dieback protection has increased from $5 million over the next 10 years to $100 million.
“This gives us the ability to intensify the great work we are doing to protect kauri. We’re working hard with the Auckland Council biosecurity team to map out exactly how and where this money will be used across the region.
“The north of Auckland is a priority area as we know it contains substantial forests of disease-free kauri and we want to keep it that way,” he says.
“We’re ramping up our efforts, but it will take full community participation – everyone using the tracks will need to be vigilant if we want to save our precious kauri.”
Visitors to kauri forest should always clean their footwear and equipment before entering kauri areas and after leaving and should use any footwear cleaning stations they encounter on their visit. They should also keep to designated open tracks.