A tree in the wrong place is set to be eradicated from Hauturu Motu/Clark Island, off the coast of Whangamatā.

Tangata whenua guardian group Tunaiti Kaitiaki Rōpū and Waikato Regional Council are partnering on a project to prevent the further spread of the island’s wilding pines, which are threatening its native flora, fauna and archaeological sites.

Hauturu is one of four islands that comprise Tunaiti Motu. Tunaiti Kaitiaki Rōpū is working towards the upkeep of the islands as wildlife sanctuaries, including eradication of all rodents since 2020.

Kaitiaki spokesperson Errol Gilbert says the removal of the pines and ongoing wilding pine management is part of Tunaiti Kaitiaki Rōpū’s efforts to restore the ngahere and native biodiversity of the motu back to their former glory.

“We need to treat the natural environment with respect and restore, improve and preserve the biodiversity values, to honour those who were before us and for future generations,” says Errol.

“Wilding pines, along with rats and mice, dogs and rubbish – they never belonged on the motu and they do not support our kaupapa.”

Kororā (little blue penguin), tītī (mutton bird), at least three species of skink and gecko, and many species of passerine birds call the Tunaiti Motu home.

But once abundant in native wildlife, including tuatara, the islands are today rated category 1 priority biodiversity sites, which mean they are critically endangered and naturally uncommon ecosystems that support threatened and at-risk flora and fauna.

Hauturu, the largest of the islands at 7 hectares, was likely cleared of vegetation prior to the early 1940s and has regenerating coastal cliff and coastal forest ecosystems.

Waikato Regional Council Biodiversity Sites Lead Jacob Dexter says the wilding pines are threatening that regeneration because of their ability to invade and impact upon indigenous ecosystems and landscapes.

“Wilding pines are a tree in the wrong place that can overwhelm landscapes, outcompeting native plants which provide food, habitat and other resources that native flora and fauna need to survive,” says Jacob.

“Production forestry may play an important role in the economy of the Waikato region, but wind-dispersed conifer seed can result in unplanned and unmanaged wilding trees that grow much faster and quickly outcompete native forest species.

“Eradicating wilding pines from Hauturu is a high priority step towards restoring the island’s ecological and cultural landscape and recreational values, not only for mana whenua but for the Whangamatā community and visitors alike.”

Work to remove the trees will begin on Tuesday (27 August 2024) and is expected to take four to five days. There will be no public access to the island while work is underway.

Jacob says some of trees are quite large and in rugged and precarious terrain, so removal will be a logistical challenge.

“The larger trees visible from Whangamatā beach will be cut down, but the smaller, less accessible trees located on the northern cliffs will require abseiling by the contractor to drill and fill them with a non-residual poison. After the initial knockdown, we’ll do a further two years of seedling and sapling removal if needed.”

About wilding pines

Wilding pines are a significant pest plant issue across the whole Coromandel Peninsula and its offshore islands. On the Coromandel Peninsula, the most common wilding pine species are Pinus pinaster (maritime pine) and Pinus radiata (Monterey pine). P. radiata is the leading production forestry species planted throughout the country, including on the Coromandel. P. pinaster is no longer used as a plantation species but its prevalence in the landscape allows it to spread where conditions allow.

Wilding pines are considered a pest for the following reasons.

• They produce abundant seeds by 10 years of age
• Seeds can be transported long distances by wind
• Seeds can germinate rapidly in open disturbed conditions, including post-fire
• They tolerate low soil fertility and drought conditions
• Seedlings can grow after being grazed or cut, and they are long lived
• They desecrate sites of cultural significance.
• They grow faster and taller than native pioneer plants by shading them out.
• Dense stands may lead to local extinction of native plant communities, drying of wetlands and riparian areas, and impact on native fauna through the loss of habitat.
• Soil and soil fauna can be permanently altered.
• They can reduce available grazing land for extensive pastoral farming.
• They limit future land-use options due to the high cost of control.
• They affect amenity and landscape values, particularly where the valued landscapes include coastal vistas (of importance for tourism).
• They can impede access to, and enjoyment of, recreational areas.
• They contribute to reductions in surface water flows, impacting on water availability and aquatic ecosystems (particularly in areas with seasonal soil moisture deficits).
• They increase risk posed by wildfire.

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