Portland tree measurement
How to measure a tree for a Portland permit
Portland uses diameter at breast height (DBH): measure the trunk diameter at 4.5 feet above the ground. If you measure circumference instead, divide by 3.14 to get diameter.
Measure a single trunk on level ground
Start 4.5 feet up the trunk from the ground. A diameter tape gives a direct result. With a regular tape or a string, wrap it straight and snug around the trunk at that height, measure the circumference, then divide by pi (3.14).
For example, a 37.7-inch circumference is about 12 inches DBH. If you are close to a City threshold, remeasure carefully and keep a photo or note of where the tape sat.
Use the City method for unusual trunks
On a slope or a leaning trunk, Portland measures at right angles to the trunk, 4.5 feet along the center of the trunk axis. The height is the average of the shortest and longest sides of the trunk.
If the trunk splits below 4.5 feet, measure the smallest circumference below the lowest branch. For a branch or bump at the measuring point, measure slightly below or above it. For a multi-stem tree with trunks connected above ground, use the largest trunk’s diameter plus one-half of each additional trunk’s diameter.
Next steps
- Measure at 4.5 feet, then record diameter or circumference in inches.
- Use the City’s illustrated guide for slopes, splits, and multiple stems.
- Remeasure borderline or uncertain results before relying on a permit answer.
Official sources
Rules can change. These City sources were reviewed on October 5, 2026. Confirm details that depend on a boundary, map record, permit history, or emergency condition with Portland before starting work.
Get a clearer path
Check your property and one tree.
Answer only the questions that matter, then see official sources and the next action.