The government is planting 54,000 new trees across the ACT over the next two years in an effort to grow canopy to 30 per cent by 2045. But not everyone is happy with the choices.
The City Services directorate says the plantings will fit in with the designated species of the street or park in question “to ensure the look and feel of the urban landscape is retained for future generations”.
About half will be native eucalyptus trees, a figure that’s striking fear into the hearts of some Canberrans who note the genus’ reputation for dropping hefty limbs onto cars and houses at random, and becoming a “widow-maker”.
“Great to see lots of tree planting going on around Tuggeranong, however, most are gum varieties,” one resident posted to the Canberra Notice Board Group on Facebook.
“Why not plant some pretty deciduous trees, especially around schools and paths, etc, where gums can be dangerous?”
These concerns echo those of Belconnen residents after a storm swept through on 3 January, 2022, downing trees and leaving homes without power for up to seven days. The clean-up stretched to three months.
In its aftermath, residents shared stories of being “terrified” of gum trees near their properties, while others said they had tried for months to have them removed by the government to no avail.
In September last year, a Legislative Assembly committee recommended the government “consider the appropriateness of tree species as part of future urban planting with regard to the risk of damage from severe weather events”.
“[Eucalypt] species are shallow rooted, making them more likely to fall over during storms, and are prone to dropping limbs. They are also tall growing, often overshadowing power lines,” the committee’s report read.
Associate Professor Cristopher Brack, from the Fenner School of Environment and Society at the Australian National University (ANU), has worked closely with the ACT Government since 1994 on choosing trees for the urban environment. He says eucalypts tick a lot of boxes.
“They work in the city, they have long life spans and they do all the things you want a tree to do in the city.”
The government considers many factors for new tree plantings, including water and nutrient availability, shading and light, safety of pedestrians, cyclists and drivers, nearby infrastructure such as underground pipes or overhead electricity cables, and environmental benefits.
According to the latest analysis, 20 of the top 50 trees chosen as suitable for Canberra’s streets are eucalypts. But Associate Prof. Brack says the native – and non-eucalypt – brachychiton populneus (commonly known as the kurrajong) still remains the number-one preference.
“It’s the single best tree we think works climate-wise and city-wise on a streetscape.”
He says natives are often chosen over exotics for their stronger drought resistance. Compared with deciduous trees, they also don’t clog Canberra’s waterways with leaf litter and promote algae blooms further down. He puts the bad rap of eucalypts down to “confirmation bias”.
“‘Widow maker’ is an old forestry term. It’s for the guys who were felling trees and not noticing dead wood or not being very practised in how you fell a tree. It’s really not appropriate for the city.”
Associate Prof. Brack says there is no evidence in the ACT to suggest eucalypts shed more limbs than any other genus of tree.
“Most of the eucalyptus trees in Canberra have dead branches up in the permanent canopy, but they’re pretty structurally solid. The only reason they do come down is when they get damaged and rot gets in them, and that can happen to any tree.”
No matter the type of tree, they all have to contend with Canberra’s soil.
“Our soil is not very deep because there’s a lot of clay low down, so often the trees are fairly shallow rooted. In general, though, the eucalypts we have planted here are generally more stable than other species.”
In the end, Associate Prof. Brack says the deciduous/native debate is rooted in personal preference.
“People either love the native trees because they don’t shed leaves or they love the exotics because they don’t shed large ribbons of bark. It’s a personal preference thing to an extent.”