NSW Department of Primary Industries temperate fruit industry leader, Shane Hetherington, said his research team at OAI have started an innovative trial to evaluate the effectiveness and cost of reworking high density apple orchards.

"We aim to demonstrate to growers how they can replace old trees with new varieties, return the orchard to full production within two years and save money by retaining expensive infrastructure," Dr Hetherington said.

"Most orchards are now taking advantage of high density production and we’re planning ahead to give them money-saving options when, every ten years, they replace trees."

Rather than knocking out old trees and replacing expensive irrigation and trellis systems, Dr Hetherington proposes that the trees are top-worked with new varieties.

"We are grafting new varieties onto the old rootstock, so not only are we keeping the valuable infrastructure, we’re also giving the new grafts a kick-start on an established root system," he said.

"We have trees at OAI which will produce fruit this season, just 12 months after grafting, and next year we predict they will have returned to full production."

High density systems offer significant production benefits - higher yield potential per hectare, uniform high quality fruit and easier harvest, canopy and pruning management - but newly planted trees usually take three to four years to reach full production.