ACT Parks and Conservation Service regional manager Brett McNamara said he was shocked to learn vandals had chopped down a number of historic trees on Friday night, leaving them to block roadways.

"One tree was a very large old pine tree which survived the 2003 bushfires only to fall victim to this mindless act of tree vandalism," he said.

"The pine tree that was cut down was well over 50 years old and the others were planted as part of a community program to revegetate the area after the fires, so there's also an emotional element."

Mr McNamara said vandalism was no longer uncommon at nature reserves as Canberra continued to expand.

"This type of vandalism has become a bit of a trend during the last few years, particularly in reserves that are up against the fringe suburbs," he said.

"These areas that were once remote are no longer so."

Mr McNamara said ACT Policing travelled to the forest after the vandalism was reported and were now investigating.

" [The vandals have] taken to that tree with an axe and just chipped away at it," he said.

"This is also a danger as swinging an axe around at night is far from safe, especially with trees falling every which way.

"Someone could have been killed."

Mr McNamara said staff were continually cleaning up vandalism at reserves around the ACT including at the Kambah Pools, Point Hut Crossing and Tharwa Sandwash.

"That's very frustrating for us and ultimately costs us money," he said.

The cost of the clean-up at Pine Island and the loss of the trees have been estimated at $3000.

ACT Parks and Conservation has called on the public to contact Crime Stoppers should they have any information about the vandalism.

"Someone must know something about this or have heard a story about someone chopping down trees on the weekend," Mr McNamara said.