Certified Arborists · Sydney-Wide
7 Warning Signs
Your Tree Needs
Professional Help
Most tree failures don’t happen without warning. Knowing what to look for could prevent a serious injury, a fallen branch through your roof — or a fine for ignoring a problem tree.
1 in 10
Chainsaw fatalities in Australia involve suspended dead branches
80%
Of major tree failures show visible warning signs weeks before the event
$1.1M
Maximum penalty in NSW for removing a protected tree without approval
The warning signs
Trees don't fail without warning.
The signs are there — if you know what to look for. This guide walks through the seven most important indicators that your tree needs a professional arborist's assessment, along with what each sign means and how urgently you should act.
Urgency guide
Critical —
Call an arborist within 24–48 hours
High —
Arrange an assessment within 1–2 weeks
Moderate —
Monitor and schedule a seasonal check
Warning Sign 01
Dead Wood & Crown Die-Back
Dead branches are the most common — and most dangerous — tree hazard in Australian residential properties. In forestry, a suspended dead branch is called a “widowmaker” for good reason: when gravity eventually wins, a falling branch of even moderate size can kill a person below or cause catastrophic damage to structures.
Dead wood is unpredictable. Unlike a healthy branch which bends and gives warning, dead wood snaps without flexing — often triggered by nothing more than a gust of wind or the weight of rain. If more than a third of the tree’s crown shows die-back, the whole tree may be compromised.
What to look for
- Branches with no leaves when surrounding ones are in full canopy
- Large sections of bark falling from individual branches
- Brittle, grey-coloured wood with no flexibility when pushed
- No new growth on a branch in spring or early summer
- Hanging or suspended branches caught in the canopy above
Critical
🪵
Critical
🍄
Warning Sign 02
Fungal Brackets & Mushrooms at the Base
Visible fungi growing from a tree’s trunk or at its base is one of the most reliable indicators of advanced internal decay. By the time fungal fruiting bodies are visible on the outside, the decay inside is typically already extensive — the fungi are simply the reproductive stage of an organism that has been consuming the tree’s heartwood for months or years.
This is particularly serious because internal decay is invisible from the outside. A tree can look healthy and full of leaves while being structurally hollow. Without a professional assessment including a resistograph or sonic tomography test, the extent of the internal damage cannot be determined by eye alone.
What to look for
- Shelf-like bracket fungi growing from the trunk or major roots
- Mushrooms clustered at the base of the tree or nearby soil
- White or yellow stringy material (mycelium) under loose bark
- Soft, spongy wood when you press on the lower trunk
- A hollow sound when the trunk is knocked with a firm object
Warning Sign 03
Sudden Lean or Structural Shift
Many trees develop a natural lean over their lifetime — this is not necessarily a problem. What demands immediate professional attention is a sudden change in lean, particularly after strong winds, heavy rain, or a dry period followed by ground saturation.
A sudden lean indicates the root system may be failing — either through root rot, structural damage, or shallow anchoring in Sydney’s coastal soils. Once roots begin to fail, the process accelerates rapidly. A tree that leans 15 degrees today can fall within hours during the next significant wind event.
What to look for
- A noticeable tilt that wasn't present or was less pronounced before
- Soil mounding or cracking on the side opposite to the lean
- Exposed or lifting roots on the tension side of the tree
- The tree appears to have "shifted" position after storms
- Cracks appearing at the base of the trunk on one side
Critical
📐
Spotted one of these signs on your property?
Our qualified arborists offer free on-site assessments across Sydney. Don’t wait.
Warning Sign 04
Bark Damage, Cracks & Cavities
The bark is a tree’s skin — its first line of defence against disease, pests, and moisture loss. Significant bark damage, vertical cracks (called “co-dominant stems” in arboricultural terms), and hollow cavities in the trunk all represent entry points for decay and structural weakness.
A cavity large enough to put your fist into is not cosmetic — it represents a significant reduction in the structural integrity of that section of trunk. In Sydney’s storm season, a tree with an existing trunk cavity is considerably more likely to fail than an intact specimen of the same size and species.
What to look for
- Deep vertical cracks running down the trunk or major branches
- Two or more trunks joined at a tight "V" angle — a structural weak point
- Open holes or cavities in the trunk, especially at the base
- Areas where bark has peeled or been stripped away exposing bare wood
- Seeping liquid or staining from cracks in the trunk
High
🌲
High
🌱
Warning Sign 05
Root Damage, Soil Heaving & Foundation Impact
A tree’s root system typically extends two to three times the width of its canopy. In Sydney’s suburban blocks, this means the roots of a significant tree are almost certainly interacting with your home’s foundations, drainage infrastructure, or neighbouring property. Root-related damage is often the slowest-moving sign — but it’s also one of the costliest to ignore.
The most serious root-related issue is when root damage compromises the tree’s own structural anchoring. A tree with significant root loss on one side — whether from construction, excavation, or rot — has an asymmetric base that may fail without obvious above-ground warning.
What to look for
- Cracking in paths, driveways, or patios near the tree's base
- Raised or heaving soil in a line from the tree toward structures
- Sewer blockages or slow drains (root intrusion into pipes)
- Roots visibly cut or damaged by recent construction or landscaping
- Soil subsidence or a bowl-shaped depression around the base
Warning Sign 06
Pest Infestation & Tree Disease
Borer beetles, termites, scale insects, and fungal pathogens can devastate a tree from within — often showing relatively minor above-ground symptoms until the damage is already severe. Borer infestation in particular is especially problematic for Sydney’s native eucalypt population and can hollow out a trunk surprisingly quickly.
Tree diseases like myrtle rust, Phytophthora root rot, and collar rot have become increasingly common in Sydney’s wetter periods. While some can be managed with early intervention, others may necessitate removal to prevent spread to neighbouring trees — which may have preservation order implications you need professional guidance on.
What to look for
- Small round exit holes in the bark — a borer's calling card
- Fine sawdust-like frass collecting at the base of the trunk
- Unusual leaf discolouration, wilting, or premature drop
- Abnormal lumps, galls, or distorted growth on branches
- Weeping wounds or excessive sap flow from the trunk
High
🐛
Moderate
⚡
Warning Sign 07
Proximity to Structures, Roofs & Power Lines
A structurally healthy tree that overhangs a roof, is growing into power lines, or has major branches directly above a swimming pool or outdoor living area represents a managed risk that needs professional oversight — even if the tree itself shows no signs of disease or decay.
In Sydney, branches in contact with or within 1.5m of power lines must be managed by a qualified arborist in coordination with Ausgrid. Attempting to prune near live power lines yourself is not only illegal — it carries a very real risk of electrocution. For rooflines and structures, overhanging branches become projectiles in storm conditions.
What to look for
- Branches growing onto or rubbing against your roof tiles
- Any limb within 1.5m of overhead power or communication lines
- Major branches directly above outdoor living areas or pools
- Canopy extending over neighbouring properties (shared responsibility)
- Trees growing within 3m of a building's foundation
Next Steps
What to do if you spot a warning sign
Don’t ignore it, don’t attempt to fix it yourself. Here’s the right course of action — whatever you’ve noticed.
01
Document what you're seeing
Take photos of the warning sign from multiple angles — close up and from a distance showing the tree's overall structure. Note whether the issue appeared suddenly or has been developing over time. This helps us triage urgency before the on-site visit.
02
Contact a qualified arborist
Call Sydney Tree Co for a free, no-obligation on-site assessment. Don't call a general handyman or unlicensed tree cutter — incorrect pruning of a compromised tree can accelerate its deterioration and expose you to significant liability if the tree subsequently fails.
03
Check council requirements first
In Sydney, significant trees are protected under council tree preservation orders. Before any works proceed, you may need council approval — especially for removal. We can advise on what's needed for your property and assist with the application where required.
“Abdul and his team identified a serious structural defect in our large gum tree that we’d completely missed. Turned out it had significant internal decay. They handled the removal safely and the site was left cleaner than when they started.”
- Elisha B., Sydney
“We called after noticing our old Port Jackson Fig was leaning slightly after the last storm. The team came out within 24 hours, assessed it thoroughly, and gave us clear options. Really appreciated the honest advice — no pressure at all.”
— Jessica S., Woollahra
“We had a 40m tree come down in a storm. Abdul’s crew were there the next morning, professional and calm throughout what was a genuinely stressful situation. Patient with our curious kids too.”
— Kate A., North Sydney
Common Questions
Frequently asked questions
Can I remove a dangerous tree without council approval in Sydney?
In most cases, no — even if a tree poses a genuine safety risk. Most Sydney councils have tree preservation orders that protect significant trees on private property. However, many councils have an emergency clause that allows immediate removal when there is an imminent risk to life or property. Sydney Tree Co can advise on the correct process for your specific council area, and we can assist with emergency applications.
How do I know if a tree is protected by a preservation order?
Protection thresholds vary by council. Waverley Council, for example, protects trees over 5m tall or with a trunk circumference over 30cm. Randwick’s threshold is 4m or 100mm diameter. The safest approach is to call your council or contact us — we’re familiar with the rules across all Sydney council areas and can tell you whether your tree is protected before any work begins.
What happens if I ignore a warning sign and the tree falls?
If a tree falls and causes damage after visible warning signs were present — and you took no action — your home insurance may not cover the claim. Insurers can argue you were aware of the risk and failed to act. Beyond insurance, if a neighbour’s property or person is injured, you may face personal liability. Early, documented action protects you legally and financially.
Does every warning sign mean the tree needs to be removed?
Not necessarily. Many warning signs — particularly pest infestations, some fungal issues, and proximity hazards — can be managed through targeted pruning, bracing, cabling, or treatment rather than full removal. Our assessments always start from the position of preserving the tree if it’s safe to do so. Removal is recommended only when the risk cannot be adequately mitigated.
How much does a tree assessment cost?
Sydney Tree Co provides free on-site assessments for residential properties across Sydney. There is no cost and no obligation to proceed with works. For formal arborist reports required as part of a council DA or development application, these are separate documents with an associated fee — we can advise on whether one is needed for your situation.
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