The ACT government has axed its preferred tree species for Northbourne Avenue, deciding instead to plant brittle gum as its builds the light rail line to Gungahlin.
Capital Metro Minister Simon Corbell will announce on Thursday plans for the tree – named Eucalyptus mannifera – instead of the its first choice species Eucalyptus rossii or scribbly gum.
A spokesman for Mr Corbell said the timing was coincidental. The change was the result of soil testing finding scribbly gum might not be suitable for the Northbourne area without additional work.
In January it was announced Northbourne Avenue's failing River gums would be replaced with eucalyptus and year-round plantings of wildflowers.
Brittle gums are multi-stemmed trees that grow to between 10 and 20 metres with a trunk spread of about 13 metres. Also known as red spotted gum, the species attracted the name "brittle" because its wood is unsuitable for furniture.
The species features a smooth white trunk with patches of grey, which changes to a pink colour in late spring or summer. A guide to native plants describes the changes as particularly pronounced when the trunk is wet after summer rains.
It has narrow dull green leaves, about 12 centimetres in length. It flowers white in autumn in the Canberra region.
The tree is common in the central and southern tablelands of NSW and is included in Canberra's National Botanic Gardens.
Mr Corbell said it was common in the Gungahlin region and on Black Mountain as well as in the median of Captain Cook Crescent in Griffith, on Northbourne Avenue's verges and at the southern end of Mugga Way in Red Hill.
"Grown for its ornamental value, it is an attractive, stately tree that is also widely planted in Canberra as an urban tree with more than 100,000 planted in streets and parks," he said in a statement.
He said the new species had been chosen after consultation with the National Botanic Gardens, the public, landscape architects, an arborist, the Provincial Nursery and Yarralumla Nursery.
The new tree choice has also been endorsed by the National Capital Authority.
As with previous announcements, Mr Corbell stressed many of the trees on Northbourne Avenue are in decline and will need to be replaced regardless of the light rail works, set to begin in 2016.
"Between 2010 and 2014 the number of trees on Northbourne Avenue and Federal Highway median of the light rail corridor reduced from 802 to just 484 through failing health, storm damage and removal of dead and dangerous trees," Mr Corbell said.
"Furthermore, the 2014 assessment of the trees in the corridor found only 59 per cent of the remaining trees were healthy."
In January, it was reported some of the trees set to be cut down could have remained for 20 years, according to a government commissioned assessment in 2010.
Northbourne Avenue will feature a planned "urban meadow" with native flowers and year-round maintenance.
Tuesday's budget signalled plans for the Barr government to make a $375 million capital contribution for the tram line, after services begin in 2019.
The government says the payment, outside the currently budget cycle, means it will pay less for the project over the long term.