by Carla Caruso

Fears about the safety of gum trees were reignited earlier this month after a large branch fell at the TreeClimb adventure park in Blue Gum Park / Kurangga (Park 20). 

However, tree advocates have called for calm, saying the circumstances were unique and you’re more likely to be hit by lightning than by a tree branch.

The limb, weighing two tonnes, narrowly missed kids on the children’s course at TreeClimb. 

The adventure park features climbing bridges connected between large gum trees.

In a statement, TreeClimb said they were “extremely thankful” no-one was hurt during the incident on Sunday 16 January. 

“We recognise that dropping tree limbs is a risk of this nature-based activity, and have always managed this with extreme diligence,” the statement read.

“Daily maintenance checks as well as three-monthly detailed inspections of each element, combined with six-monthly full arborist reports on every tree, make up our ongoing schedules. The inspection was completed, and the area has once again been cleared for business.”

The branch has since been removed with consulting arborist Marcus Lodge inspecting it on-site the next day. 

He told The Advertiser that the limb had a pruning wound not visible from the outside. “I suspect the most likely thing is that it got bent in a wind maybe a week or two ago, and then with a change in temperature over the last couple of days, [that] might be just enough to cause any crack to open up and give way basically.” 

While the incident was unfortunate, Dr Darren Peacock, the National Trust of SA’s CEO, said Aussie trees should still be celebrated. 

In November, the Trust launched a Save Our Trees Facebook page, highlighting the alarming loss of mature trees to development across the state. 

“We do know that there are more deaths from lightning strikes than falling tree branches, so the risks shouldn’t be overstated,” Dr Peacock said.

“The risk of being fatally injured by a falling tree is one in 5 million; being struck by lighting is one in 1.6 million. So, it is really three times more likely to be struck by lightning than killed by a falling tree.”

This is echoed by a 2019 paper, A Review of Deaths in Australia from Accidental Tree Failures, by Mark Hartley and Jessica Chalk.

Among the findings, the authors said:

·      “The majority of fatalities occur as a result of storm damage. As a result, the greatest harm from trees is likely to occur when large trees are plentiful and when people are spending time outdoors driving or recreating during a storm or high wind event.” 

·      “When the risk [of tree failure] is small, there is an increased likelihood of an unintended consequence when trying to manage that risk. The removal of lower branches over a building serves as a good example of this principle. Removing the lower branches over a roof to reduce risk can result in a higher branch, which may have previously been slowed or stopped, now being able to freefall onto the roof and do even more damage. For this reason alone, it would seem appropriate to minimise the extent of any unnecessary interference with the trees.”

·      “A death rate per tree in Australia that is smaller than Britain’s may surprise many Australian arborists who consider eucalypts to be ‘widow makers’. It would appear that eucalypts may provide no greater risk and perhaps a lower risk than the average tree in Britain.”

·      “The cost of trying to find a ‘killer tree’ is disproportionate to the risk posed… In the case of the death of Bridget Wright in a [NSW] school playground, the ensuing inspection of all trees in the 2500 or so public schools resulted in the removal of 9000 trees. The coroner found that ‘there was nothing to indicate any specific concerns about the large forest red gum tree in the playground on that day’. Had the tree been inspected before the death, it is likely that the tree would still have been there, and the death would have occurred in any case.”

·      “In addition to this, there are unintended costs [of tree removal]. For example, it is conceivable that at some stage we will see a small spike in melanomas as a result of the loss of trees. In some schools, the loss of trees was sufficient enough to have caused other health issues, such as an increase in the rate of asthma attacks.” 

The paper also said that most people are comfortable being exposed to risks many times greater than that posed by tree failure. 

Consider the following mortality rates for Australia (figures rounded):

• by melanoma – 1 in 13,500

• driving – 1 in 20,000

• asthma – 1 in 60,000

• murder – 1 in 100,000

• falling from a bed – 1 in 420,000

• animals – 1 in 830,000

• fall involving a chair – 1 in 1,000,000

• accidental tree failure – 1 in 5,000,000, and

• accidental tree failure while inside a house – 1 in 189,000,000.