Canberra needs to have a uniform policy on urban green scapes while the city loses more trees than it's planting, an ACT parliamentary inquiry has heard.
Professor Ken Taylor, who has previously written a book on Canberra's natural environment, fronted an inquiry on the capital's green spaces on Wednesday.
He pointed to the capital's original vision as "a city beautiful with garden city overtones".
"We are losing more trees than we are planting. It's alarming," Professor Taylor said.
Separately, research was released this week which showed only four other local government areas in Australia were doing worse than Canberra when it comes to tree canopy loss.
The data came from a 2017 report from 202020 Vision funded by the nursery industry, which showed Canberra lost more than 10 per cent of canopy cover between 2009 and 2016.
The report gathered data from 139 local government areas across Australia, with the ACT counting as one.
RMIT Associate Professor Marco Amati said it was concerning in a large jurisdiction like the ACT, with two national parks, that there had still been a two per cent increase in hard surfaces.
"I think that's actually more concerning [than canopy loss]," Professor Amati said.
"I would recommend that if the government could make some sort of commitment that whatever increase you get in hard cover ... were also ensured by an increase in canopy cover."
Professor Amati said the canopy reduction drop was possibly due to dieback - trees dying from various causes - and development in Canberra.
The report showed a 10.9 per cent loss in tree canopy cover between 2009 and 2016 with a 0.9 per cent lost in shrub cover over the same period.
Grass cover - including pastures and development sites - increased by 9.4 per cent along with a 2.2 per cent increase in hard surfaces, which includes asphalt and car parks.
"The fact that the ACT has lost around more than 10 per cent of the canopy and has seen little compensation in terms of shrub growth puts it basically ... well, basically there's only four other [local government areas] out of 139 that are doing worse."
Professor Amati said two of those areas, Nilumbik in Melbourne and Nedlands in Perth, were urban areas.
But it was the other two, Glenorchy in Tasmania and Pittwater in NSW, that were similar to the ACT in the amount of parkland.
Professor Amati said a loss of tree cover created hotter environments.
"You've got to balance the long term social, economic and health costs of not having trees in the urban environment."
A heat map of Canberra showed Fyshwick, an industrial area in the capital's east, was one of the hotter parts of the city.
There was also a large hot in Canberra's north around the developing suburb of Moncrieff in Gungahlin.
Professor Amati said the country had made behavioural changes around green spaces near urban fringes after devastating bushfires, including the 2003 Canberra bushfire.
"Trying to sort of say we can't have trees near houses because of bushfires is actually a bit of a furphy," he said.
Professor Amati said emergency responses and publicly available resources had done more to help with bushfires than fuel reduction.
Wednesday's inquiry heard Canberrans concerns about the rise of higher density development infiltrating lower density zoned suburbs.
Griffith Narrabundah Community Association member David Denham said this would result in a reduction in green spaces in the city.
"When you look around the city ... little pockets of RZ2 invading the garden city of RZ1," Mr Denham said.
Reid Residents Association president Marianne Albury-Colless said non-native trees had wider canopies than native species.
"Wide canopied trees are essential if we're going to mitigate climate change," Ms Albury-Colless said.