Inner south residents are concerned for the health of a tree at the centre of a long running stoush that has prevented the owner of the Capitol Theatre from building a six-storey hotel on a prominent block.
The 18.5-metre-tall London plane tree, which stands in the way of the proposed Manuka development, has had branches and leaves turning brown since November.
A spokesman for the Transport Canberra and City Services directorate confirmed it was aware of the issue and its tree protection unit was investigating.
The tree is fenced off from the public pathway on Franklin Street and a trench appears to have been dug close to the tree's trunk, which is located between the Capitol Theatre building and an unoccupied restaurant building. It is not known when the trench was dug, nor whether it might have affected the health of the tree.
Photographs taken by The Canberra Times in November and January show the browning of leaves in a central patch rising from the tree's trunk.
David Denham, a member of the Griffith Narrabundah Community Association and the Inner South Community Council, said he was shocked when he noticed the degradation in the tree on Monday.
"When I peered over the wall to look at what has been done with this excavation, then there's no wonder it's in a bad state because all its roots in that direction have been mutilated," Mr Denham said.
"I don't know how long the trench has been there. I've never looked over the black tape or black guard of it, so I don't know what will happen now ...
"Mature trees are few and far between because of intensification in various areas and because of the way the planning rules work."
Inner south residents have fought hard against the hotel development. Mr Denham said this week residents were concerned by its "ad hoc" nature and insufficient car parking for the proposed hotel.
He believed the site could be redeveloped to bring life back to the precinct but a new development should consider how best to use the block as a whole.
Asked about the browning of the leaves, site owner Sotiria Liangis, who has lodged plans to redevelop the site, told The Canberra Times there was little she could say about the tree but the government conservator had "inspected the premises". She was unable to be reached again regarding the trench before The Canberra Times' deadline.
The ACT's chief planner, Ben Ponton, has allowed the tree to be removed if the Conservator of Flora and Fauna, Ian Walker, removes the tree from the tree protection register.
Amendments to planning laws could force Mr Walker to follow Mr Ponton's lead and deregister the tree.
Submissions to the conservator about the tree's deregistration closed on December 7.
Mrs Liangis said she was unable to say whether the tree would be removed.
Mr Ponton approved the tree's removal in November, pending the conservator's decision, despite advice from the interim National Capital Design Review Panel, which urged the authority against approving the proposed development because it failed to meet the high architectural standards required under National Capital Authority rules.
The panel met in March 2018 and also concluded the development application did not justify the removal of the tree.
When the tree was placed on the tree register in 2012, it was said to be an "exceptional quality tree" that was relatively disease free.