New Zealand — Contorta pine trees were 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. …They suck water out of river catchments, change soil biology 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”.