A protected tree at the centre of a long-running stoush over the planned redevelopment of the Capitol Theatre cinema complex has been found with a drill hole at its base.
A spokesman for Transport Canberra and City Services said no offender had yet been identified as being culpable for the vandalism, which was found as part of an investigation by the directorate's tree protection unit.
"Tests by an independent laboratory did not detect the presence of any poisons," the spokesman said.
In late January, inner south residents expressed concerned for the health of the London Plane tree after its branches and leaves started turning brown.
At the time, Transport Canberra and City Services said it was aware of the concerns and had started investigating.
The tree appeared in good condition when it was photographed by The Canberra Times in November, but in January a large portion of its leaves had turned brown.
ACT Conservator of Flora and Fauna Ian Walker has been reviewing the protected status of the tree, with the Environment, Planning and Sustainable Development directorate so far declining to release submissions to that review.
If Mr Walker removes the tree from the register, it would allow for the redevelopment of the Capitol Theatre cinema complex into a hotel.