Tree Height by Angles: Use a Horizontal Distance and a Shared Observation Point; illustrative quantitative diagram
Define the quantity before calculating
A distance measured along a slope is not automatically the horizontal distance required by the equation. Both angles must refer to the same observation position and a suitable tree reference. A different geometry needs a matching method.
Use Tree Height Calculator with the units and the basis stated on its form. Check what each input represents before carrying the output into another record.
Read the model explicitly
Height m = horizontal distance × [tan(top angle) − tan(base angle)].
The Trees & Forestry Calculators group sits within Biology calculators. Keep a measured observation distinguishable from a hypothetical input when moving between its tools.
A worked unit check
| Input as labeled on the tool | Illustrative value |
|---|---|
| Horizontal distance to the tree reference line (m) | 20 |
| Signed angle to the identified top (degrees) | 45 |
| Signed angle to the base (degrees) | -5 |
| Output from the illustrative inputs | Value | Unit |
|---|---|---|
| Trigonometric height estimate | 21.7498 | m |
Record the original input and its unit with this result. Recalculate when the measurement basis changes; changing a unit label after calculation does not convert the quantity. More decimal places do not remove sampling or measurement uncertainty.
A related quantity
Tree Diameter Calculator addresses a related part of the task. Check its own input definition before carrying a number across.
Continue with Tree-Top and Base Angles: Signed Measurements Can Change the Height Estimate for the other part of this measurement question.
Return to GreenCalc for other subjects. Keep raw observations, chosen assumptions and calculated quantities identifiable so a later revision does not overwrite the basis of the original record.
By GreenCalc · Updated 2026-11-06