A working reference for the Australian Standards we apply in practice, together with occasional field essays on trees, planning and the long view.
Pruning of Amenity Trees
The Australian Standard governing how, where and to what extent amenity trees may be pruned. It defines acceptable pruning types, branch-collar cuts and the limits of crown reduction.
Protection of Trees on Development Sites
The framework for retaining trees through design, demolition and construction. Sets out tree protection zones (TPZ), structural root zones (SRZ) and the role of the project arborist.
Tree Risk Assessment — Best Management Practice
The International Society of Arboriculture's framework underpinning the TRAQ qualification. Provides a defensible methodology for assessing the likelihood and consequence of tree failure.
Queensland Development Codes & Local Planning Schemes
State and local-government instruments that determine how trees are treated through development assessment — including significant tree registers, vegetation protection orders and offset frameworks.
Short pieces from the practice — written for arborists, planners and the merely curious. New entries appear irregularly.
Infrastructure is depreciated; trees appreciate. A short argument for treating canopy as the most underrated piece of capital on a council balance sheet — and what that means for the way we write retention conditions.
Every other asset a council owns is a depreciating one. The road wears, the pipe corrodes, the building loses a percentage point of book value each year until it is written down to nothing. Trees do the opposite. A semi-mature Lophostemon planted into a verge today is, in real terms, the cheapest version of itself it will ever be. In thirty years that same stem will be shading a footpath, cooling a wall, intercepting a rainfall event and adding measurable dollars to every property within its drip-line — and it will have cost the city almost nothing to keep there.
Most encroachments fail not on the numbers but on the narrative. A working method for writing tree-protection conditions that survive the construction phase intact.
AS 4970 is short. The whole document fits in a back pocket and most of it is diagrams. The trouble is that the parts everyone reads — the TPZ formula, the 10% encroachment threshold, the SRZ calculation — are the easy parts. They are arithmetic. The hard part is the half-page that asks the project arborist to provide an arboricultural justification when the encroachment exceeds the threshold or when the works fall within the SRZ. That paragraph is where most reports quietly fail.
Notes from four years installing artificial habitat across the City of Gold Coast — what worked, what didn't, and what an 85–90% occupancy rate actually means in practice.
The program started, as most useful programs do, with a problem we were already paying to solve. Every week the city was removing trees that had reached the end of their structural life — eucalypts and pines in parks, road reserves and bushland edges, most of them with hollows that had taken eighty years to form. The removal was justified. The loss was not accounted for. A natural hollow on the Gold Coast is, on average, more than a century old, and there is no plausible regeneration pathway that replaces one inside a planning horizon.
Risk is not zero, and zero risk is not the goal. A frank look at how TRAQ reframes the conversation between arborist, asset owner and the community downstream of every limb.
The phrase 'safe tree' is one of the most expensive two-word combinations in the language. It is what a client asks for when they want certainty, what an insurer reaches for when they want to apportion blame, and what an arborist should never, under any circumstances, sign their name to. A tree is a self-loaded biological structure standing in a wind field. The honest answer to 'is it safe?' is always 'compared to what?'.