Vandals have destroyed 375 genetically modified radiata pine trees at a research site in Rotorua, causing about $400,000 worth of damage.
The tress, planted at forestry research site Scion to test herbicide resistance and study reproductive development, were destroyed over Easter weekend, chief executive Warren Parker told Radio New Zealand.
The trees were protected by electric fencing.
"Somebody broke in through the three security fences - dug under the final one - and either pulled out or cut off 375 plants ... It is outright vandalism,'' Dr Parker said.
The damage would set back the eight-year research project by about a year, Dr Parker said.
An attack on the trees in 2008 prompted Scion to increase security with high-voltage electric fencing, electric alarms and security patrols.
