by Carla Caruso
Gum trees have been in the spotlight recently, after a branch almost fell on children at a city aerial park.
As previously reported, the limb narrowly missed kids on the children’s course at TreeClimb in Blue Gum Park / Kurangga (Park 20). The adventure park features climbing bridges connected between large gum trees.
To better understand the dangers associated with such trees, I spoke to Adelaide ecologist Vicki-Jo Russell. She’s the program manager of revegetation services at Trees For Life.
The not-for-profit organisation works with everyday people to help restore our natural environment through bushcare and revegetation.
Vicki-Jo snapped this ‘urban’ river red gum in Clarence Gardens. “I love [trees like] these as the streets have gone around them and they just bring their urban nooks to life.”
Hi, Vicki-Jo. Why do gum trees drop branches?
“There is no single agreed explanation for why gum trees drop branches. It is often attributed to a combination of factors that include weather conditions, the health and age of the tree, the tree’s growth habit such as crown weight and symmetry or the strength of branches at their junctions, and the presence of friction, damage or physical stress on the branches.
“Branch drop is likely to be a resilience measure, allowing the tree to jettison a branch to protect the whole tree.”
There’s a community perception that gum trees can drop limbs at any time, without warning. Is this true? Or are there signs that people can look out for?
“Gum trees can drop limbs at any time and without warning, but they are more likely to drop them in summer, during periods of hot or humid weather, and/or during strong winds.
“Limb drops are also more likely to happen in older or less healthy trees, and once a tree has dropped a limb, it is more likely to do so again before the end of its life.
“Trained arborists can often pick up signs of disease, physical stress or damage, weak junctions or potential issues with tree crown growth, and in many cases, treat the risk.
“To reduce the risk, avoid sitting underneath large gum trees during hot and/or windy weather.”
This beautiful river red gum was captured by Vicki-Jo in Edwardstown.
Are river red gums riskier than other types? Are older gums also ‘riskier’?
“A large number of medium and large trees drop branches but Eucalyptus (gum) trees are one of the most common Australian genus to do so, and in South Australia, River Red Gums (Eucalyptis camaldulensis) and Sugar Gums (Eucalyptus cladocalyx) are the most susceptible. Limb drops are more likely to happen in older or less healthy trees.”
Should parents be worried about their children playing in city parks?
“While there is a risk of falling branches associated with some large old gum trees, their magic and value to people and wildlife alike is undeniable.
“Even without sitting directly underneath them, we all enjoy the benefits of their beauty, interest, shade, and shelter.
Young cyclists ride the BMX track amid gums in Blue Gum Park / Kurangga (Park 20).
“My children spent many hours playing in open spaces and gardens with large gums. We always exercised caution during periods of hot, windy or stormy weather - and areas recovering from fire - and kept a few metres out of the footprint of their canopy.
“However, in the context of a year, these periods are brief and infrequent, and it was a small inconvenience to be able to enjoy these trees for generations.
“Many councils do inspections of significant trees in their parks to identify and treat vulnerable or damaged trees.
“If parents have any concerns, they should get in touch with their local council to see what management is in place and to allow them to investigate.”
