Eucalyptus Branch Drop: Why Eucalyptus Tree Branches Keep Falling

Eucalyptus Branch Drop: Why Eucalyptus Tree Branches Keep Falling

By: Teo Spengler

Eucalyptus trees (Eucalyptus spp.) are tall, beautiful specimens. They adapt easily to the many different regions in which they are cultivated. Although they are quite drought tolerant when established, the trees can react to insufficient water by dropping branches. Other disease issues can also cause branch drop in eucalyptus trees. Read on for more information about falling eucalyptus branches.

Eucalyptus Branch Drop

When eucalyptus tree branches keep falling from the tree, it may mean that the tree is suffering from disease. If your eucalyptus tree suffers from an advanced rot disease, the leaves wilt or become discolored and fall from the tree. The tree may also suffer eucalyptus branch drop.

Rot diseases in the tree occur when the Phytophthora fungi infects the roots or crowns of the tree. You may be able to see a vertical streak or canker on infected eucalyptus trunks and a discoloration beneath the bark before you see falling eucalyptus branches.

If dark sap oozes from the bark, your tree likely has a rot disease. As a result, branches die back and may fall from the tree.

If branch drop in eucalyptus signals a rot disease, the best defense is planting or transplanting the trees in well-drained soil. Removing infected or dying branches may slow the spread of the disease.

Eucalyptus Branches Falling on Property

Falling eucalyptus branches do not necessarily mean that your trees have a rot disease, or any disease for that matter. When eucalyptus tree branches keep falling, it may mean that the trees are suffering from extended drought.

Trees, like most other living organisms, want to live and will do whatever they can to prevent demise. Branch drop in eucalyptus is one means the trees use to prevent death in times of severe lack of water.

A healthy eucalyptus tree suffering from long-term lack of water may suddenly drop one of its branches. The branch will not show any sign of disease on the inside or the outside. It will simply fall from the tree to allow the remaining branches and trunk to have more moisture.

This presents a real danger to homeowners since the eucalyptus branches falling on property can cause damage. When they fall on human beings, injuries or death can be the result.

Advance Signs of Falling Eucalyptus Branches

It is not possible to predict the falling eucalyptus branches in advance. However, a few signs may indicate possible danger from eucalyptus branches falling on property.

Look for multiple leaders on a trunk that might cause the trunk to split, a leaning tree, branch attachments that are in a “V” shape rather than a “U” shape and decay or cavities in the trunk. If the eucalyptus trunk is cracked or the branches hanging, you may well have a problem.

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What Is Sudden Branch Drop Syndrome?

Just like you and me, trees are living organisms meaning they can get sick, go through cycles, have problems, or experience unexplained issues.

One “condition” or “syndrome” a tree can have is sudden branch drop syndrome, which is exactly how it sounds. The tree drops branches onto the ground, suddenly. When this occurs, you cannot tell if another branch will fall again or not. If your tree dropped a branch or branches, this can be unsettling. You don’t want anyone or anything to get hurt. However, is sudden branch drop syndrome bad? Is the tree sick? Is it dying? Is this a normal thing for a tree to do?

Sudden Branch Drop - The Facts.

With summer here again we thought it prudent to remind those new to bushwalking, or new to Australia, about the unpredictable and dangerous phenomenon of SBD, or Sudden Branch Drop.

As seen on the Great Ocean Walk, Victoria

The simple fact is that eucalyptus trees sometimes shed perfectly healthy limbs without warning, and if you are sitting or camping underneath the affected branch at the time you risk injury or death. Eucalypt branches are dense due to their high resin content and a moderately-sized limb can cause thousands of dollars of damage to a sturdy property, never mind a flimsy nylon hiking tent.

I personally experienced SBD a couple of years ago while camping in Glenworth Valley, NSW. We'd spent the night under a big old eucalyptus, maybe 3m from the trunk, and were making breakfast when a huge limb on the other side of the tree suddenly dropped off and crashed into the ground, snapping into three pieces and gouging a couple of large divots out of the soil. We were flabbergasted! It missed our (empty) tent by a couple of metres, but had it happened in the night and a bit closer, we would've been toast.

The reason the trees drop healthy wood is self-preservation. In times of drought or sometimes even just a regular summer, they may need to reduce their water consumption to increase their chances of survival. Just like a human with gangrene, they are better off losing one part of their body than dying altogether the difference is that they are thinking ahead. Unfortunately for outdoors men and women, there may be no outward sign of weakness or disease. The only warning is a loud cracking noise if you hear that, run away as fast as possible!

Whilst SBD is undetectable in advance, there are other reasons that eucalypts can drop branches so it pays to be on the look out. According to

"Rot diseases in the tree occur when the Phytophthora fungi infects the roots or crowns of the tree. You may be able to see a vertical streak or canker on infected eucalyptus trunks and a discoloration beneath the bark before you see falling eucalyptus branches. If dark sap oozes from the bark, your tree likely has a rot disease. As a result, branches die back and may fall from the tree."

When bush camping it can be impossible to find a spot that isn't underneath a eucalyptus tree, but before you swear never to venture outdoors again, human injuries are rare and there are ways to minimise risk. Pay particular attention to species that have been identified as more likely to suffer SBD, which include yellow box, maiden's blue gum, mountain ash and red river gum. The worst times are late in the day or early in the morning during dry spells or outright droughts, and horizontal limbs shed more often than those angled upwards. Lastly, older trees are more prone.

Three hours and two metres from a tragic end to my One Planet Goondie tent , Glenworth Valley, NSW

It's important to know about SBD, but don't let it control your bush experiences. You're probably as likely to get struck by lightning. Focus on the more prevalent dangers out there, like snakes, bush fires and drop bears.

Sudden Limb Drop……

Limbs can fail due to heavy and unnecessary loads of foliage or genetic defect, but there is another cause happening all around the Bay Area. It is called “sudden limb drop phenomena,” or sometimes referred to as “sudden branch drop.”

The phenomena causes limbs to break commonly on hot and windless days, with no obvious external signs of defect or trauma to the tree. The inner wood is broken bluntly (round and flat breakage), as opposed a breakage with sharp splintering.

Arborists studying sudden limb drop, or sudden branch drop, have found no consistent causes or visible warning signs. Some arborists theorize that sudden branch drop may be caused by change in branch movement, moisture changes, ethylene gas released inside the branches, however there are still no definitive answers.

So what can you do about it? First understand which trees commonly suffer from sudden limb drop. They include, but not limited to:

Eucalyptus Quercus
Ulmus Procera
Fagus Sylvatica

Next, reduce the risk. Trees are living organisms and arborists can not always detect when, and which limbs will fall. But we can imply measures for prevention of sudden limb drop the best we can.

1) Prune at risk tree limbs for crown thinning.
2) Install a cable system to limit motion and share the load with other limbs or nearby trees.
3) Request an Arbortek Arborist to visit your property to identify at-risk trees.

What is another name for eucalyptus tree?

Gum tree is a common name for smooth-barked trees and shrubs in three closely related genera of Eucalypt: Eucalyptus, which includes the majority of species of gum trees. Corymbia, which includes the Ghost gums and Spotted gums.

Secondly, what are eucalyptus trees used for? Eucalyptus is a fast-growing evergreen tree native to Australia. As an ingredient in many products, it is used to reduce symptoms of coughs, colds, and congestion. It also features in creams and ointments aimed at relieving muscle and joint pain.

Beside above, how do I identify a eucalyptus tree?

Examine the leaves of the tree that you suspect is a eucalyptus tree. Eucalyptus leaves are long and pointed with smooth sides and a leathery texture. Under a magnifying glass, you can see glands throughout the leaves that secrete oil. Explore the branches of the tree.

What does a eucalyptus tree look like?

Eucalyptus can vary in form from a short shrub to a tall, evergreen tree. The bark is a blue-grey colour and peels off in strips to reveal yellow patches underneath. Sometimes, a red resin exudes through breaks in the bark, hence the tree's other name – the gum tree.

That sounds like sudden branch syndrome, also called summer branch drop or sudden limb failure. During calm, but hot, summer days, seemingly healthy tree limbs simply snap and fall off.

We’re not quite sure why this happens. But s ome trees are more prone to this–specifically, aging trees as well as sycamore, oak, elm, eucalyptus and beech trees.

What should I do if this happens?

T end to your tree as soon as you notice a problem. The first fall might come unannounced, but trees afflicted by sudden branch syndrome may shed a few more.

So, act quickly, assess your tree’s health and take measures to reduce injury or damage. More on that below!

C an I prevent this?

That’s a tough question because we don’t know for sure why this happens!

There are a few common theories about what causes sudden limb failure. Some experts say it’s triggered by high humidity within the tree’s canopy, which leads to a surplus of moisture that weakens the tree’s structure. Others think it stems from an internal tree issue, like bacterial wetwood .

Even after decades of research, the cause is still up for debate. Because of that, it’s hard to say how exactly to prevent this.

But there are a few steps you can take to decrease the likelihood of summer branch drop:

  1. See a large chunk of your tree on the ground? H ave a n ISA Certified Arborist ® inspect the rest of the tree. They’ll look for dead offshoots , decay or other visible hazards. Then, because your tree could be at risk, plan to get it inspected annually for the next few years.
  2. Get ready to trim ! Of course, you’ll want to remove any unsafe tree limbs. But you should also see which sections of your tree may be at risk because of their weight or internal decay. Finally, your arborist may recommend pruning to open up the canopy , which reduces humidity .
  3. Keep the tree as healthy as possible with regular plant health care practices . That means watering, mulching, trimming and fertilizing.

Not sure your tree’s structure is sound? A sk your local arborist to take a look.

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Tools to Prevent Against Sudden Limb Drop

Sudden branch drop has been known to happen along lines of weakness however, it is also possible in branches with no apparent flaws. Therefore, it is hard to predict. In general, it’s a good idea to keep an eye on your trees, especially large, mature trees. Older oaks, maples, ashes, beeches, and elms are common victims of sudden branch drop, but it has occurred in dozens of other species as well. Trees with large, horizontal limbs with an upward sweep at the tips are more likely to suddenly drop limbs. Oftentimes, branches that suddenly drop are those that extended beyond the tree’s main canopy.

While inspecting your trees, look for discoloration, particularly a darker spot where water appears to be “bleeding” out of the tree. This is a sign of a potential limb flaw, which could contribute to limb failure.

Do not place benches or tables below older trees that may suffer sudden limb drop.

As always, consistent, expert Portland tree pruning is the best preventative action you can take to protect your trees from sudden branch drop. Schedule regular tree maintenance with our Portland Oregon certified arborists. Our ISA-certified arborists are pruning masters with expertise on how to best cut to minimize the chances of sudden branch drop. Portland tree trimming from less experienced, less knowledgeable pruners may leave excess foliage at the end of limbs, thereby increasing the burden the tree must support on hot, dry days. Sudden branch drop is dangerous for bystanders and detrimental to tree health. Protect against it with regular, professional pruning from a top arborist tree service company near you.

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“Great service from UFP. I’ve hired them on multiple jobs, and I find them very professional, quick, and careful. I won’t hesitate to call them again when I need an arborist.”