Tree Height Estimator

The shadow method uses similar triangles to estimate the height of a tall object. At the same time of day, all shadows maintain the same ratio to their object height.

Tree Height = (Tree Shadow Length / Stick Shadow Length) × Stick Height

Unit conversions:

• Imperial: Measurements in feet
• Metric: Measurements in meters

How to measure:

1. Place a stick (or any known-height object) upright in the ground near the tree
2. Measure the stick height (the part above ground)
3. Measure the stick shadow length on the ground
4. Measure the tree shadow length on the ground
5. All measurements must be taken at the same time (shadows change as the sun moves)

Tips for accuracy:

• Measure on a sunny day with clear shadows
• Take measurements on flat ground — slopes will skew results
• Measure from the base of the object to the tip of the shadow
• A 4-foot (1.2 m) stick works well — easy to measure, long enough shadow
• For best results, measure when shadows are longer than the objects (morning or late afternoon)

Alternative methods:

• Clinometer/phone app: Use angle + distance from tree
• Known reference: Compare to a nearby object of known height (e.g., a person, a story of a building is ~10 ft / 3 m)