Tree Appraisal by the CTLA Trunk Formula
The arborist bench is all biomechanics - decay, cavity, protection zone.
Example
You enter
- Trunk diameter (in) 24
- Unit tree cost ($ per sq in of trunk) 60
- Species rating (%) 80
- Condition rating (%) 70
- Location rating (%) 75
You get
- Trunk area sq (in) 452.389
- Basic value (undepreciated) $27143
- Combined factor 0.42
- Appraised value 11400.2
- Depreciation (%) 58
Details, formula, and sources
Rigging - and none of it answers what a tree is WORTH, which is the number a claim or removal dispute turns on. Value = unit cost x trunk AREA x species x condition x location, so it goes as the square of diameter: a 24-in trunk at $60/sq in and 80/70/75 ratings appraises near $11,400 against a $27,143 basic value. Every factor is a regional input; no table is shipped. An estimating aid, not an appraisal.
appraised value = unit tree cost ($/sq in) x trunk cross-sectional area (pi/4 d^2) x species rating x condition rating x location rating; trunk measured at 4.5 ft above grade over 12 in diameter, 1 ft at or below.
The CTLA (Council of Tree and Landscape Appraisers) trunk formula method, by name; no unit-cost or rating table is reproduced - all four are regional inputs.
The trunk formula's structure is published across extension and industry references; regional unit costs and ratings come from a plant appraisal committee guide.
Estimate. AHJ and licensed professional govern.
Field names used by the API: dbh_in, unit_cost_per_sq_in, species_pct, condition_pct, location_pct, trunk_area_sq_in, basic_value, combined_factor, appraised_value, depreciation_pct
- Area, not diameter value goes as the square of trunk diameter through the cross-sectional areaCTLA trunk formula
- Measurement height 4.5 ft above grade over 12 in diameter; 1 ft at or belowCTLA trunk formula
- All factors regional unit cost and the three ratings are entered from a regional plant appraisal committee guideuser input