Ernslaw One is a vertically integrated softwood plantation company with the fourth largest forest estate in New Zealand.
Ernslaw One formed in New Zealand in 1990 when it purchased the cutting rights to a number of the state forests in the Coromandel, Southern North Island, and Otago. It also purchased the Conical Hill sawmill near Tapanui. In the mid-1990’s, the forest estate was expanded through the buying of farmland and establishing new plantation forests. This growth occurred in three main areas, being Gisborne, Southern North Island and Otago-Southland. In 2004, Ernslaw One purchased the cutting rights to the ex-state forests on the East Coast of the North Island from the receivers of Huaguang Forests. In 2008, WPI International was purchased, adding additional forests, a sawmill and a pulp mill in the Ohakune region to the company's estate.