THE more than 100,000 trees greening Newcastle's public spaces are valued at almost $20 million, new figures show.
Civic strategists have been analysing leafy areas as part of a Newcastle urban forest policy.
Since the policy was adopted in May 2008, Newcastle City Council has developed an asset management system for the city's trees.
New communities and green corridor principal strategist Ian Rhodes said tree canopy covered 21 per cent of the local government area.
The 103,000 public trees have a replacement value of $19.5 million.
Mr Rhodes said trees in urban areas provided environmental, social and economic benefits.
"They act like the lungs of the city, they filter the air and the water," he said.
Civic Park and Laman Street had a strong sense of place because of tree-lined avenues.
Trees' aesthetic appeal could also boost property values.
The council is working towards quantifying the money that trees help save in stormwater, pollution and energy costs, and to set a target for an appropriate level of canopy cover.
Consulting arborist Ian McKenzie initiated the urban forest policy in his former role as a Greens councillor.
Mr McKenzie said green assets were just as important as other infrastructure such as buildings and sewers.
"There's a lot of evidence that shows that having a garden environment in which to live actually improves the quality of life," he said.
"It's an important part of your city infrastructure to invest and make sure that it's there," Mr McKenzie said.