Gum Trees, a.k.a the Widowmakers

Gum trees (like the trees in question hanging over our house) are often referred to as the widowmakers. This post outlines some external reports on how this nickname was earned.

• "River reds and many other eucalypts have an ominous nickname, "widow maker", as they have a habit of dropping large boughs (often half the diameter of the trunk) without warning." [wikipedia]
• "GIANT eucalypts have a habit of dropping heavy branches to save water during droughts, earning them an ominous nickname, ''widow maker''." [The Age]


• "Knox City Council is felling about 400 spotted and scented gums in suburbs such as Rowville, where residents are fed up with the damage done by thirsty roots, falling limbs and messy leaves." [The Age]
• The council cut down about 70 towering gums on Goulburn Drive late last year after being forced to pay thousands of dollars in compensation to individual home owners and their insurance companies who have complained about structural damage to homes and driveways from the gums.
• Tree roots have caused Mr Hartley's water pipes to burst and have sucked the earth so dry the grass won't grow. Leaves, twigs and black sap drop on his house every day clogging up guttering.


• "Giant eucalypts have a habit of dropping heavy branches earning them the nickname of Widow Maker. These gum trees preserve their health during periods of drought or inadequate water supply by allowing some branches to dry out and break off – a sort of self pruning. [1]
• "Huge branches falling from 30 or 40 metres to the ground can do some real damage, and there have been recorded incidents of death to people due to this – hence the nickname."
• "I can recall vividly on no less than eight or nine occasions hearing a crash and realising that a huge branch had fallen. " [1]
• On three or four occasions it happened in daylight hours and one on one occasion I can recall actually looking at a tree in the distance and to my surprise and somewhat shock, watching as a huge branch simply dropped off an enormous gum tree. 
• Some years ago at Tweed Heads we had a great deal of rain and high winds, several trees had fallen on houses and cars around the area. We had two very large trees a little way behind the house and the SES gave us the okay to remove them as there was at least a modicum of a chance of them falling. 
• "Can you tell if a tree is so stressed that a big branch is about to fall off? You can't tell whatsoever," says Victor. Perfectly good branches just seem to break off. It's very, very difficult, and probably impossible to say." [ABC news]
• "They're perfectly fine [on the outside] and the inside, they seem to be structurally sound - a lot of the trees that I look at that have dropped limbs, you could not pick that they were going to fall."
• "As an arborist, I definitely don't sit under old eucalypts: I might get a bit paranoid after dealing with so many of them, but you can never tell."
• "often called to such incidents when the temperature rose above 30 degrees [this week there is a 45 degree heat wave, how scared should I be? should I move my family to a hotel?], because big gums were more likely to drop their limbs in the heat." [npaact.org.au]
• "a family with two young children was lucky to escape serious injury when a gum tree fell on two cars in Stamford Street"
• "Mr Sainsbury said gum trees were dangerous and did not belong in urban areas."
• "Arborists warn that branches can fall at any time and cars should not be parked under them." [but it's ok to live underneath one for 24/7?]

Or how about this from the Government Parks Health and safety website:

• Trees and limbs may fall unpredictably. Being under or near trees may be dangerous and could cause injury. Trees can drop limbs, or entire trees can fall, without warning and there is no way of determining when. 
• Be aware that it may be dangerous to set up camp, park your car and picnic under trees as limbs can swing out beyond the drip line (the edge of the canopy) of a tree.
• As there is no way to predict exactly when a tree might fall or drop a limb it is ALWAYS better to be safe than sorry.

So the Government recognizes the risks of these trees, and warns people to be very careful and vigilant when visiting national parks. But living under one of these trees is somehow fine and less of a risk?

Here are some recent reports of deaths caused by falling branches:

• "A large branch from a 50-year-old gum tree fell and landed on top of three students and a teacher on Friday afternoon...Eight year-old Bridget Wright, a horse lover and high-achieving year 4 student, was pinned beneath a limb of the towering tree and died" [SMH]
• "A YOUNG woman fatally struck by a tree branch while setting up for a NSW music festival is being remembered for her “beautiful manner and way with people”. [Daily Telegraph]
• The parents of a young man with a severe disability are outraged the ACT government refused to remove a tree they considered dangerous, then two branches fell through the roof and wall of their son's bedroom. [Canberra Times]
• A smaller branch ripped a 15-centremetre hole in the bedroom's wall, through which sunlight was visible.
• "A tree that killed a young girl and injured her mother when a branch fell on top of them at a Bendigo park was not considered hazardous by council authorities, a coronial inquest into the child's death has heard."
• The court also heard the tree had six limbs arising from one trunk, which posed a potential danger. [this is similar to our tree]
• "Wind damage was reported in several areas, with SES crews receiving more than 70 calls for help, mainly for trees down and damaged roofs." [couriermail.com.au]
• That's 70 trees down in just one night of strong winds.
• "FOUR schoolgirls have been injured after being struck by a fallen tree branch in Sydney’s south." [news.com.au]
• A NSW Ambulance spokesman said one girl suffered head injuries, and two suffered back injuries.
• All four were taken to St George Hospita

You might be thinking that this doesn't prove anything. It's just random bad luck, and the risk of it happening to us is minimal. 

That's not really the case though, for the following reasons:

• These trends show these gum trees are particularly know for being unpredictable, with seemingly healthy trees dropping branches without notice, especially in hot weather, like the recent Sydney heat waves.
• Council tree inspectors sometimes get it wrong. Inspecting a tree and saying it's "healthy" doesn't really guarantee anything. These Gum trees are notorious for being unpredictable.
• Many of the reports above are of people being killed by trees in public places (parks, schools, etc). The chances of this happening are extremely low (you generally have more chance of winning the lotto). 
• But when you have one of these trees hanging over your head 24 hours a day for your whole life, that risk increases tremendously! 

Given all this evidence and precedent, it's hugely irresponsible and negligent to be gambling with people's lives like this. The risks are recognized and acknowledged, and tourists are warned to be very wary when bush-walking in national parks. But living under one is somehow ok, because they look pretty in the suburbs? 

If the council likes these trees so much, then they should declare the danger zones around them uninhabitable and not let people own land and build dwellings there. Yet obviously this is not the case. The council happily charges us money to live there, while telling us to just put up with the danger: its an "acceptable risk" apparently.


"But not all Gum trees are the same"
For a bit of clarification on the trees on my property: One of the problematic trees overhanging my place is a Sydney Red Gum, or "Angophora costata", which is not strictly not an eucalypt, but very closely related and according to this Maquarie University paper, shares the characteristic of dropping branches without notice.

"Angophora does have its dark side and its propensity to drop branches without warning has earned it the name Widow Maker."

The other big tree is a Lemon-Scented Gum (Corymbia citriodora), which also shares this trait: [1, 2]

"Lemon scented gums, like many eucalypts are prone to dropping branches at random, even when they’re healthy. That’s why they’re nicknamed ‘Widow Makers.’ So when they’re sick, they’re not a tree to take lightly."