Measure tree diameter with your Android phone

Arboreal Tree for Android now includes AR-based diameter measurement — validated in the field against a caliper.

For the last year, iPhone users have been measuring trunk diameter straight from the Arboreal Tree app. Today, we're bringing the same feature to Android.

Point your phone at the trunk, mark the edges in AR, and the diameter appears instantly — stored alongside height, crown width, crown height, inclination and GPS location. No caliper. No tape. Just your phone.

What's new in this release

Diameter measurement — the headline feature. Measure trunk diameter at breast height with your camera.

Performance and UX polish — faster captures, smoother AR tracking, and a refined measurement list so your tree inventory is easier to browse and review.

How it works

1. Activate - open the settings and activate diameter measurement
2. Aim — start measurement, point the camera at the trunk at breast height.
3. Mark — When the red lines are on each side of the trunk and the green marker in the middle, press the button.
4. Read — the diameter appears on screen and is saved with the rest of the tree's measurements.

The whole flow takes a few seconds per tree. For anyone surveying a stand, that adds up fast.

How accurate is it?

Accurate enough that we're comfortable putting real numbers on it.

We validated the Android release against a digital caliper on 31 trees, spanning diameters from 8.0 to 43.8 cm across mixed species.

Metric	Value
Mean absolute error	0.80 cm
Systematic error	0.07 cm
RMSE	1.02 cm
Standard deviation	1.01 cm

In terms of how often the phone is "close enough":

• 74.2% of measurements landed within ±1 cm of the caliper
• 90.3% within ±2 cm
• 100% within ±3 cm

For field inventory work — where caliper readings themselves have some measurement noise — that's squarely in the "usable" range.

Who is this for?

Arboreal Tree is built for people who need real numbers from the forest without carrying a bag of extra tools:

• Foresters running inventories and growth studies
• Arborists documenting trees in urban and private settings
• Researchers collecting plot data at scale
• Landowners who just want to know what's in their woods

Everything you capture lives on your device, tied to a GPS location and a photo of the tree.

Get it now

Arboreal Tree for Android is available on Google Play today.

Download on Google Play »

If you're already using it on iOS, thank you for a year of feedback — this release wouldn't exist without it. And if you're on Android and try it out, we'd love to hear how it performs in your forest.