Dead eucalypts line the hillside behind Kerikeri's stone store. Photo: RNZ / Peter de Graaf
Up to 50 large gum trees have been poisoned near Kerikeri's historic Stone Store.
The poisoning has shocked Kerikeri residents and forced the Department of Conservation to close a popular track to keep walkers safe.
The department's Pēwhairangi/Bay of Islands operations manager, Bronwyn Bauer-Hunt, said Hongi Hika Track had been closed due to the risk of dead trees toppling over in high winds.
Bauer-Hunt said DoC was discussing options for the dead eucalypts with local hapū Ngāti Rēhia and Heritage New Zealand.
Those options included felling and removing the trees, felling them and leaving the debris on the ground, or allowing the trees to fall naturally, though that was unlikely.
The track where the poisoned trees are located starts at a carpark just uphill from the Stone Store.
Dead gums now form a backdrop to the Stone Store when New Zealand's oldest stone building is viewed from the other side of Kerikeri River.
Bauer-Hunt said the poisoning came to light when local residents spotted a man in the reserve drilling holes in tree trunks.
Dead gum trees loom over a car park just uphill from the Stone Store. Photo: RNZ / Peter de Graaf
He was now helping DoC staff with their enquiries.
The man believed he was doing the right thing, she said.
"We believe the offender was trying to do good. He thought he was adding value to conservation by removing pest trees, or non-indigenous trees."
It was thought the "drill and fill" operation to poison the trees was undertaken over a roughly three-month period.
Bauer-Hunt could not comment on whether DoC was considering prosecution given the investigation was ongoing.
About 50 mature eucalypts had been affected along with a number of smaller Taiwanese cherry trees.
DoC's immediate concern stemmed from the trees' location along a popular track, potentially putting people in danger.
The eucalypts were not native but formed part of the Kerikeri landscape, especially in the heritage precinct.
Drill holes can be seen in the trucks of the dead eucalyptus trees. Photo: RNZ / Peter de Graaf
"They also happen to be growing on a kāinga (the village that used to next to Hongi Hika's pā) so there are places within that particular stand of trees that have heritage values, particularly for local hapū."
The track closure would have only a minor impact on visitors because alternative walking trails were available.
The trees are within Kororipo Heritage Park, which includes Kerikeri's historic Mission Station, the Stone Store, Ngāpuhi chief Hongi Hika's pā and the kāinga.
The park is managed by a committee made up of representatives from Ngāti Rēhia, DoC, the Far North District Council, Heritage New Zealand and others.
Committee chairman Kipa Munro said hapū were concerned about the use of poison in the park as well as the risk falling trees posed for track users.
"From a Māori perspective our role as kaitiaki is not only to do with the environment and the ngahere (forest), it's also the people who use the area."
Regardless of whether the trees were native or exotic, they had a place in the local landscape.
"If the public have concerns about anything in the park they should come to us to discuss that … This was an act of someone taking it on themselves to decide which trees should remain or be removed."
It is not the first time trees have been poisoned in the Bay of Islands.
In a case that outraged residents on the north side of Kerikeri Inlet in 2018, a row of pōhutukawa trees was poisoned on a beachside reserve at Opito Bay.
It was found herbicide had been poured into holes drilled into the base of each tree.
It is believed police identified a suspect but did not have enough evidence to prosecute.
The pōhutukawa recovered after a treatment applied by a Kerikeri arborist.
In 2020 a large number of roadside trees planted as part of a community project died near Waimate North, though in that case the poisoning was accidental and caused by an over-zealous spray contractor.