The trees that come down during a storm get cleaned up in the first 24 hours. Chainsaws, a skip, insurance photos, done. The trees that matter more are the ones still standing — the ones that took structural damage, moved at the root plate, or lost the neighbour that had been sheltering them for thirty years, and did not fall.
Why the risk peaks after the storm, not during it
Three mechanisms, all of which leave a tree standing but compromised.
Root plate movement
Saturated soil plus wind load lets the root plate rotate without the tree going over. The tree returns to near-vertical when the wind drops. The root-to-soil bond that held it there is now broken. It looks the same from twenty metres away and it has lost a large fraction of its anchorage.
Partial failures
Cracked unions, split limbs and hanging branches lodged in the canopy. A hung limb is not stable. It can come down in still air, hours or weeks later, and it is called a widow maker for a reason.
Exposure change
The least intuitive one. Trees grown in a group develop structure suited to a sheltered wind regime. When the storm removes one of them, the survivors are suddenly carrying loads they never adapted to. That risk does not present until the next wind event.
Secondary failures cluster in the period immediately after the event, while soils are still saturated, damaged unions are still loaded and hung limbs have not yet worked loose. That is also the period when people are outside cleaning up, which is exactly the wrong combination of high failure likelihood and high target occupancy.
Where clean-up goes wrong
Two patterns, both common on the Sunshine Coast after summer storms.
- People work under the damaged trees. The debris is beneath the tree that shed it, so that is where everyone stands. If the tree shed one limb because of a structural problem, the problem has not gone anywhere.
- Only the visible damage gets addressed. The fallen limb is removed, the hung limb three metres higher is not noticed, and the root plate movement is not looked for at all.
A ground-level check before you send anyone in
- Walk the base of every significant tree. Look for cracked, lifted or heaved soil, particularly on the side opposite any lean. This is the single highest-value check.
- Look up before standing under anything. Hung and partially detached limbs are the most common cause of post-storm injury.
- Check unions and stems for new cracks. Fresh splits are pale and often weep.
- Note any tree whose neighbours have gone. Flag it for assessment before the next event, not this one.
- Compare lean against a fixed reference. A fence line, a building edge, an old photograph. New lean is significant; long-standing lean with adapted growth usually is not.
For duty holders specifically
If you run a workplace, a park, a school, a club or a body corporate scheme, a significant storm should be a standing trigger for re-inspection in your documented tree management policy — not a judgement call made on the day. Section 19 of the Work Health and Safety Act 2011 (Qld) turns on what you knew or ought reasonably to have known. After a major storm event, “ought reasonably to have known” expands considerably.
Write the trigger into the policy: a defined wind speed, a declared severe weather event, or visible damage on site. Then it happens automatically and the record shows it happened.