Police are investigating vandalism around a geothermal landmark south of Rotorua last weekend.
The vandalism affected planting work at the popular Waiotapu Hot and Cold Pools to help areas degraded by foot traffic to recover.
Police say the area was vandalised on Saturday night, tarnishing recent restoration efforts.
They say 10 kanuka trees with some at least 50 years old were hacked down and wooden railings cut, probably with a chainsaw.
The species, prostrate kanuka, is nationally threatened.