On Tuesday, volunteers arrived at the Jean Malpas Community Nursery in Kelvin Heights for their weekly potting day, part of their overarching goal to reforest the Wakatipu Basin with native plants.
However, they discovered seven 18-month-old red beech trees had been stolen from the site.
Wakatipu Reforestation Trust trustee Neill Simpson said it was "pretty disappointing".
"We’re planting this whole area, bringing it right through to replace the [wilding] pine trees and get something a bit more like New Zealand.
"I [went] around the back two weeks ago and they were all there then [so] it’s been within the last couple of weeks [they’ve been stolen], I’d say."
Trust management group member Greg Thompson said the 2m-high trees were worth about $25 each, but it was about more than just money.
"It’s pretty annoying when a volunteer group is doing all of this.
"We’re putting about 10,000 natives into the area every year. We’ve got plenty, but that’s not the point really — this has set it back 18 months."
It was not the first time the trust had noticed plants going missing.
Trust volunteer Helen McPhail said "at least 30" plants, largely lancewoods, had been taken from the Peace Park, near Remarkables Primary School at Frankton Beach, over about 18 months.
"We suspect they’re after one particular species," she said.
"Because they were recently planted, it was just a case of lifting them out."
Whoever took the beech trees will need to have an extra-green thumb — Mr Thompson said it was unlikely they would survive now — and a large property given they grow to about 30m.
