Controlled Burn Trial Targets Invasive Wilding Pines in Central Otago

Wilding conifers, often referred to as wilding pines, spread aggressively across farmland and conservation areas.

A 50-hectare controlled burn of wilding conifers has been carried out in Central Otago, marking a new step in New Zealand’s fight against one of its most damaging invasive weeds. The burn, overseen by Biosecurity New Zealand and scientifically monitored by Scion Group, forms part of the National Wilding Conifer Control Programme’s research efforts.

Why Wilding Pines Are a Problem

Wilding conifers, often referred to as wilding pines, spread aggressively across farmland and conservation areas. They outcompete native plants, disrupt ecosystems, and lock up land that could otherwise be productive. Left unchecked, wildings can cover large tracts of land within decades, costing communities, farmers, and the environment.

Biosecurity Minister Andrew Hoggard stressed that tackling the issue is vital for both the economy and the environment.

“Wilding pines are invasive weeds that take over farmland and conservation areas, locking up land that could be productive. Fixing what matters means making sure landowners can use their land again.”

Controlled Burning as a Management Tool

While the most common methods for wilding pine control involve mechanical removal or herbicide spraying, controlled burning is being tested as a complementary technique.

The goal of a burn is to reach temperatures high enough to destroy not only the trees but also the cones and wilding seeds in the soil, preventing regrowth. If successful, controlled burns could reduce the frequency and cost of follow-up control measures.

However, Minister Hoggard acknowledged the challenges:

• Burns can only be carried out in strictly suitable weather and environmental conditions.

• Safety precautions must be rigorous to protect people, wildlife, and surrounding ecosystems.

• Currently, burning is not widely used and is typically employed only by some private landowners.

Science at the Heart of the Trial

The Central Otago burn was closely monitored using scientific equipment placed around the site. Measurements were collected before, during, and after the fire to assess:

• The intensity and duration of the burn.

• The effectiveness in destroying cones and seeds.

• The overall ecological impact.

Post-burn monitoring will continue to evaluate whether the method is a cost-effective and scalable solution for future wilding control efforts.

Protecting Communities and the Environment

The trial is part of a practical, science-led approach to solving one of New Zealand’s most stubborn environmental problems. If proven successful, controlled burns could offer landowners an additional tool to reclaim their land and restore it for farming, conservation, or community use.

“By trialling methods like controlled burns, we can see which techniques are working and focus resources where they make the biggest difference – helping landowners reclaim their land, strengthening our economy, and protecting our environment for the future,” said Hoggard.

Looking Ahead

With wilding pines spreading across an estimated 1.8 million hectares nationwide, New Zealand’s long-term control strategy requires innovation, collaboration, and persistence. The controlled burn in Central Otago could pave the way for broader adoption of fire as a targeted management technique, complementing existing control tools to ensure a more sustainable future.