The Parangarahu Lakes and surrounding landscape were returned to the Regional Park in 2004 following the cessation of a grazing licence to a local farmer. The area was to be allowed to regenerate naturally. However the land surrounding the Lakes has been so comprehensively modified by Maori settlement and European farming, very little indigenous vegetation remains and there is no close seed source to drive this regeneration.
Greater Wellington commissioned a plan from the ecologist Geoff Park who recommended a strategy of assisted restoration to encourage a speedier rate of return to a native forest and scrub cover than will occur without assistance. He proposed the planting of fenced plots, which would exclude stock, goats and hares. Firstly, hardy pioneers would be planted and subsequently secondary canopy trees, as canopy closure is achieved. Trees are all sourced from MIRO’s Gracefield Tree Nursery
The first plot was established in winter 2007 near Lake Kohangapiripiri, and plots continue to be added annually. Initial plantings are made of 800–1000 trees and these are infilled as required. As these trees flower and fruit, birds will spread the seed into the surrounding landscape of gorse and manuka/kanuka scrub speeding up the natural process of regeneration.