The Perth Storm Season Checklist Every Homeowner Ignores

Every June we have the same conversation at 2am with someone standing in their driveway in a dressing gown looking at a limb through their patio roof. And almost every time, the tree gave warning months earlier that nobody was looking for.

Perth's storm season runs roughly June through August. Cold fronts come off the Indian Ocean with sustained winds, they land on ground that has just gone from bone dry to saturated, and trees that stood fine for thirty summers go over in a night. The physics is simple: a full canopy acts as a sail, and sand or clay that has taken 40mm of rain in six hours no longer grips a root plate.

Here is what to do in April and May so you are not the driveway phone call.

1. Walk the base of every large tree

You are looking for cracks in the soil on the opposite side to the lean, soil that looks mounded or lifted near the trunk, and any gap opening between trunk and ground. That is root plate movement and it is the single most reliable predictor of a whole-tree failure. If you see it, ring an arborist that week, not next season.

Also look for fungal brackets. Shelf-like fungi growing out of the trunk or the buttress roots mean decay inside the structural wood. The tree can look perfectly healthy up top while the load-bearing timber is compromised.

2. Look up and find the dead wood

Stand back far enough to see the whole canopy against the sky. Bare grey limbs with no leaf are dead and they will come down, the only question is when and on what. Marri and lemon-scented gum are particularly good at holding dead wood for years before releasing it.

Deadwooding is one of the cheapest jobs we do and one of the highest value. A crew can clear the dead material out of a mature tree in a couple of hours.

3. Check the branch unions

Where two limbs of similar size fork off the trunk at a tight V-shaped angle, that union is weak. Included bark gets trapped in the joint and the two stems push each other apart instead of growing together. Under storm loading, these split. If you can see a vertical crack running down from the fork, that tree needs attention now.

U-shaped unions with a wide angle are strong. Tight V-shaped unions on a big tree are a liability, and they can often be managed with cabling or selective weight reduction rather than removal.

4. Get the crown thinned, not topped

The most effective storm-proofing available is crown thinning: selectively removing internal branches so wind moves through the canopy rather than pushing against a solid mass. Combined with end-weight reduction, taking the heavy leverage off the outer ends of long limbs, it dramatically reduces the load a storm can apply.

What does not help is topping. Cutting the tree's leaders back to stubs makes it push out dozens of fast, weakly attached shoots. Within three or four years you have a denser canopy sitting on wounds that never sealed, which is materially more dangerous than what you started with.

5. Clear the roof and the gutters of tree first

Any limb resting on or overhanging a roof is a lever. In wind it moves, and what it moves against is your tiles or your colorbond. A crown lift to get clearance above the roofline is fast, cheap and stops a whole category of damage.

Same for anything within about two metres of a powerline running to your house. Western Power has clearance requirements around service lines and we work to them.

6. Know your species

Different Perth trees fail in different ways and knowing which one you have tells you what to watch for:

• Marri drops limbs. Sudden limb drop happens in still hot weather as often as in storms. Watch the long horizontal limbs.
• Lemon-scented gum gets very tall very fast and sheds branches from height. Planted far too close to houses across the western suburbs.
• Tuart is generally robust but holds enormous mass. When one does fail, it takes whatever is underneath.
• Cocos palm drops fronds and heavy seed pods year round. Not a storm issue so much as a constant one.
• Peppermint in coastal sand is prone to whole-plate failure once the ground saturates.

7. Sort out access before you need it

This one is unglamorous but it matters. If a tree comes down in your backyard at midnight, the crew needs to get gear in. Locked side gates with no key at the property, boats parked across the only access, and dogs in the yard all add time to a job you are paying an after-hours rate for.

What to do if it fails anyway

If a tree or limb is down on your house, get everyone away from underneath and from any wall or gutter the tree is touching. If any part of it is on or near powerlines, ring Western Power on 13 13 51 and stay at least eight metres clear. Treat every line as live.

Then photograph everything before anyone cuts anything, because your insurer will want it. Then ring us.

The best outcome, though, is the call you make in April instead. Book a pre-season assessment and we will walk your trees and tell you what actually needs doing, which is usually less than people expect.