When a tree looks healthy from the outside, it can still be hiding serious internal decay, cavities, or fungal damage that puts your property and family at risk. This is where sonic tomography comes in – one of the most reliable tools modern arborists use to see inside a tree without cutting into it.
At Green Vanguard, we use advanced diagnostic techniques alongside traditional visual assessments to give Sydney homeowners an honest, evidence-based picture of a tree’s structural condition. Here’s what sonic tomography actually involves, and why it matters before you make a decision about pruning, retaining, or removing a tree.
What Is Sonic Tomography?
Sonic tomography is a non-invasive testing method that measures how sound waves travel through a tree trunk. Small sensors are attached around the circumference of the trunk, and a technician taps each sensor with a hammer. Sound travels quickly through solid, healthy wood and slows down when it passes through decayed, hollow, or cracked timber.
A computer maps the timing differences between sensors and generates a cross-sectional image of the trunk, similar in concept to a medical CT scan. The result is a clear visual showing exactly where decay is present, how far it extends, and how much sound wood remains to support the tree.
Why It’s More Reliable Than a Visual Inspection Alone
Many trees that fail during storms show few or no external warning signs beforehand. Decay fungi often work from the inside out, meaning a tree can look green and structurally sound while quietly losing the strength it needs to stay upright. A qualified arborist report that includes sonic tomography data gives you objective, measurable evidence rather than a guess based on appearance alone.
This is particularly important for:
Large or Mature Trees Near Homes
Older trees are more prone to internal decay simply due to age and years of exposure to storms, drought, and pest activity. If a large tree overhangs a house, driveway, or shared fence line, knowing its true structural condition is essential.
Trees Flagged for Council Assessment
Many Sydney councils require documented evidence before approving a tree removal application, particularly for significant or heritage-listed trees. Tomography results give council assessors concrete data to support a removal or retention decision.
Trees With Visible Wounds, Fungal Growth, or Past Damage
Old pruning wounds, storm damage, or fungal brackets on the trunk are all indicators that internal decay may be present. Tomography confirms how far that decay has spread internally.
What Happens After the Scan
Once the scan is complete, our arborists interpret the results alongside a full visual and structural assessment of the tree, its site conditions, and its target zone (what it could fall on). We then provide clear recommendations – whether that’s continued monitoring, crown reduction to lower load on a weakened trunk, cabling and bracing, or removal where the risk is too high to manage safely.
Sonic Tomography and Tree Protection Plans
Tomography results are also a valuable part of a broader long-term tree maintenance plan. Rather than reacting to a problem once it becomes visible, homeowners can use this data to schedule preventative work, monitor decay progression over time, and budget for future tree care with confidence.
Book a Professional Assessment
If you have a tree on your property that concerns you – whether it’s showing early warning signs or you simply want peace of mind before a big storm season – Green Vanguard can arrange a full in-person assessment, including sonic tomography where needed, across Lugarno, Oatley, Como, Jannali, Illawong, and the wider Sutherland Shire and St George areas.
Contact Green Vanguard today on +61 422 810 801 to book a professional tree health assessment.