Arborist report software built for AS 4970:2025
AS 4970:2025 changed the language councils expect to see. DBH is now DSH. The calculated zone is now the Notional Root Zone, and the TPZ is what you actually determine and protect. The old Tree Management Plan is gone, split into a Tree Protection Plan drawing and written Tree Protection Specifications.
If your templates still say DBH and treat 12 × DBH as the TPZ, every report you send tells the assessing officer it was written against a superseded standard. ArborFlow reports in the 2025 terminology, DSH and NRZ, from the first tree you record.
What changed in 2025, and what ArborFlow does about it
| AS 4970:2025 change | What it means on a job | What ArborFlow does |
|---|---|---|
| DBH replaced by DSH, still measured at 1.4 m | Same tape, different word in every table | Records and reports DSH throughout |
| Calculated zone is now the NRZ (DSH × 12, minimum 2 m, maximum 15 m, clause 3.2) | The NRZ is a calculation, not your protection boundary | Calculates NRZ and SRZ for every tree, combining multi-stem trees into one DSH |
| Encroachment assessed as a percentage of NRZ area, in three categories: minor, moderate and major (clause 3.3) | Percentage of NRZ area lost drives the impact rating | Calculates encroachment percentage and labels each tree minor, moderate or major |
Built for the way reports actually get assessed
- Council-ready output. Reports are structured the way assessing officers read them: tree schedule, NRZ and SRZ, encroachment, then your recommendations.
- Planning overlays pulled in for you. In South Australia, ArborFlow checks the Regulated and Significant Tree Overlay and the other planning overlays for the site, straight from SAPPA.
Built by a consulting arborist
I've worked in arboriculture for more than 12 years and still run a consulting practice in Adelaide. ArborFlow started as the tool I needed for my own development reports. Every report it produces has to stand up in front of an assessing officer, because mine do.
— Jordan Thomas, founder
Try the free TPZ/SRZ calculator
Frequently asked questions
Is the TPZ gone under AS 4970:2025?
No. The NRZ is the calculated zone (DSH × 12). The TPZ is the zone the project arborist determines and protects, which may differ from the NRZ where design or construction controls justify it.
Does DSH change how I measure?
No. It's still measured at 1.4 m above ground. Only the term changed.