Ecosystem effects

Wilding conifers change New Zealand’s native ecosystems by competing with plants and animals for sunlight and water.

These trees can quickly colonise and change ecosystems where there is no native forest, such as above the bush line, in mineral belts and in tussock grasslands. Once there, they outcompete other species. Their effects include:

  • forming a closed canopy of shade and acidifying the soil, evicting native plant species and the animals that rely on these
  • changing the distinctive look and conservation values of our New Zealand landscapes, such as iconic alpine tussock lands
  • limiting eco-tourism and recreation opportunities
  • fueling devastating wild fires.


1998 2004 2015 wilding spread4

Wilding conifer spread in 1998, 2004 and 2015 in Mid-Dome, Southland
Image: Environment Southland

Wilding conifer forests also don’t have firebreaks or ponds, so fires are difficult to manage and can quickly spread into neighbouring areas. And it’s even a big challenge just accessing the remote alpine areas that conifers often colonise. 

Biosecurity wilding pine2 GCI marlborough