Doc Wakatipu bio-assets manager Barry Lawrence, Arrowtown Cub Scouts and volunteers completed the planting of about 150 young native trees on about 1000sq m of the scenic reserve behind the Arrowtown Cemetery extension on Saturday.
Mr Lawrence said the Arrowtown Village Association, Suburban Estates Ltd and Doc initiative aimed to restore Feehly Hill to "an approximation of pre-human vegetation - minus the moas".
A canopy of flowering kowhai is intended to grow on 2ha to 3ha.
Native shrubs, including coprosmas and olearias, would be re-established to provide berries and insect habitats, which would attract native birds, such as tuis and wood pigeons, from 2km away.
About $100,000 had been spent on the project, mostly in the form of time donated by Suburban Estates, Mr Lawrence said.
Feehly Hill had been burned many times and used as a ram paddock by Mt Soho station in the past.
Animals had spread native grass-choking weeds, such as broom, throughout the bluffs.
Mr Lawrence said Landcare Research found there were once almost impenetrable kowhai canopies on dry and flat areas throughout Central Otago, which had since been intensively farmed.
Remnants of those canopies, featuring kowhai trunks of up to 50cm in diameter, had been spotted on the northern faces of the Remarkables and Deer Park Heights, but kowhai were entirely absent from Feehly Hill.
"We did a trial planting two years ago and the results have been extraordinary, with 80 kowhai, and in two growing seasons, they've tripled in size," Mr Lawrence said.
"The hill had a lot of wilding pines and that was an ecological threat.
"The department's priority was to get rid of the wilding pines and the only effective way is to establish a canopy of species which aren't a problem.
"We can do this and have the added amenity of increasing native bird numbers."
More than 3ha at the top of the hill will be kept clear of introduced weeds, as indicated by the Queenstown Lakes District Council-initiated Arrowtown community planning workshop in 2002.
Dry native grasses, including hard tussock, will be allowed to regenerate.
Beech forest would be re-established on about 2ha on the shady side of the hill facing Millbrook, Mr Lawrence said.
"Hopefully, it will be the first of several projects with the community and developers to improve the biodiversity of reserves we have around the district."
