Contorta pine trees were meant to be our friend.

Written by Bill Morris, on behalf of Frank Film, May 2026

Introduced from North America and planted with abandon across Aotearoa for erosion control, timber and shelterbelts, contorta have rapidly adapted to our environment and spread at an alarming rate into farmland and conservation land. They now infest nearly a million hectares of the South Island. As Frank Film discovered, they’ve become our worst weed.

Wilding pines have been described as our generation's rabbit plague. They suck water out of river catchments, change soil chemistry and quickly swamp tussock grasslands and pastures, creating an acidic monoculture in which little else can survive. There are at least ten species of pine that have become problematic–including Douglas fir, Scots pine and larch, but contorta is the undisputed wilding king.

Over a lifetime spent working with trees, retired tree scientist Nick Ledgard has seen this disaster unfold. Contorta, he says, “was thought to be a bit of a wonder tree, but it’s turned out not to be the case.” In the mid 20th century, there was widespread concern about erosion in the high country. The Forest service trialled various species of introduced pine tree to hold hillsides, and contorta proved a winner. It was hardy, fast growing, and adapted well to New Zealand conditions. In fact, they did even better here than in their native range. In New Zealand, says Ledgard, “they don't have all the insects, fungi, birds, mammals and diseases that attack them in their home.”

Contorta pine cones can produce up to 70 seeds, and there are hundreds of cones on each tree. Being very fine, the seed can spread easily — “it's like dust in the wind,” says Ledgard. Contorta seedlings quickly infest grasslands downwind of a seed source.

They grow rapidly, and within four years can be producing seeds of their own. In the worst-hit areas, such as the Mackenzie Basin and parts of Molesworth Station, wilding trees can form a dense forest. Dealing with them at this stage is enormously expensive–Ledgard estimates the central government has spent at least $100 million tackling the wilding pine problem. Regional councils, he says, have probably spent a similar amount. And finally, after decades of work, they’re winning in many areas — the trees have been pushed back.

In Canterbury’s Craigieburn range, for example, a concerted effort over two decades has seen a pine-smothered landscape returned to tussock. When Frank Film visits the Craigieburns, a Forest and Bird volunteer group is busy chopping out contorta seedlings. Aiden King has been doing this for 20 years. “When I first started,” he says, “we'd take two bus loads of people up here. We'd form a line in a field and walk forwards, [pulling out trees]…and then next year we'd come back and we'd do the same thing again in the same field.” The years of perseverance have paid off – the group is no longer having to cover old ground each time. “It feels like we're winning now,” says King.

However in recent years, government funding for pine control has withered, and Ledgard fears this could see some areas, like the Craigieburn Range, slide backwards.

Wilding contorta are no good as a commercial crop – they don't grow straight enough and harvesting them is difficult. But maybe there’s a way we can put them to work.
At Pukaki Downs station, manager George Ormond has cleared huge swathes of contorta from his once-infested property. He’s cutting them down, chipping them and selling the material to Pioneer Energy to make biofuel. He tells Frank Film some of this biofuel is headed for the Makihihi Fries factory in South Canterbury – using chips to make chips.
It is, says Ormond, a win-win scenario, “instead of spending money using spray, this way you get completely rid of the forest and it's a resource rather than just a waste.”
“Unfortunately, there doesn't seem to be an appetite amongst anyone else to do it.”
In the 2026 Budget the government has pledged 79 million dollars towards the control of wilding pines. Ledgard hopes it’ll be enough to get the job done once and for all. But pine control, he says, is a zero-sum game. “The last few percent have got to be got rid of,” he says, “otherwise they'll produce seed and we'll be back where we started.”




Thanks to:

Nick Ledgard
Ray Goldring
Maree Goldring
Aiden King
George Ormond
Tony Benny

Archive Supplied by:

Tiaki Maniatoto
Environment Southland
Nick Ledgard
Richard Bowman
Wilding Pine Network
Boffa Miskell
Ministry for Primary Industries/Tony Benny


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