Tree Value Calculator — CTLA Trunk Formula Method
Estimate the amenity value of a tree using the Council of Tree and Landscape Appraisers (CTLA) trunk formula method — widely used by arborists, insurers, and courts to calculate compensation for tree removal or damage.
inches
Currency
Basic value × species × condition × location ratings (CTLA trunk formula method)
- 1
Trunk cross-section area
π × (20 ÷ 2)² = 314.16 - 2
Basic value
314.16 in² × 27 = 8,482.3 - 3
Combined adjustment factor
0.75 × 0.8 × 0.6 = 0.36Species, condition, and location ratings are each between 0 and 1. - 4
Appraised tree value
8,482.3 × 0.36 = 3,054
How does this calculator work?
Tree value (CTLA trunk formula) = trunk area (in²) × unit price/in² × species rating × condition rating × location rating. The 2019 CTLA guide uses ~$27/in² (USD, editable). Species, condition, and location factors each range 0–1, assessed by an arborist. This estimates amenity value, not timber price.
Formula
How this is calculated
The CTLA Trunk Formula Method (also called the "formula method") is the most widely used approach for appraising the value of established trees too large to replace with nursery stock. The basic value is the cross-sectional trunk area (in square inches, measured at DBH) multiplied by a replacement cost per square inch derived from current nursery and installation costs — the 2019 CTLA Guide for Plant Appraisal suggests approximately $27 per square inch (USD), but this figure is updated periodically and varies by region. Always adjust this figure for your local market and currency.
The basic value is then multiplied by three adjustment factors, each rated from near 0 (worst) to 1.00 (best): species rating reflects the relative horticultural and aesthetic value of the species in the local landscape; condition rating reflects the health, structure, and functional longevity of the specific tree as assessed by a certified arborist; and location rating reflects the contribution the tree makes at its specific site, considering visibility, prominence, and site contribution.
The CTLA method is an estimation tool for amenity (ornamental and environmental) value, not timber market value. It is commonly used in insurance claims, legal disputes, municipal valuations, and development impact assessments. A full appraisal for legal or insurance purposes should be performed by a certified arborist or ASCA-registered consulting arborist using the latest edition of the CTLA guide.
Frequently asked questions
The 2019 CTLA Guide to Plant Appraisal sets the unit price at approximately $27/in² (USD) based on the installed cost of the largest commonly available nursery tree. This figure is periodically updated; earlier editions used different values. It represents a replacement cost baseline — adjust it for your country, currency, and current nursery prices.
CTLA and various regional bodies publish species rating lists. Long-lived, site-adapted, aesthetically valued trees (mature oaks, elms, specimen maples) rate 0.80–1.00. Common, short-lived, or invasive species often rate 0.20–0.60. Your local arboricultural society or extension service may publish region-specific ratings.
No. The CTLA trunk formula estimates the amenity value of a standing landscape tree — its contribution to the environment, aesthetics, and property. Timber market value (sawlog price) is a separate calculation based on species, log grade, and commodity markets. Urban amenity values typically far exceed timber value for established trees in residential settings.
Also known as
TG we-Calculate Editorial Team. (2026). Tree Value Calculator — CTLA Trunk Formula Method [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/tree-value-calculator
TG we-Calculate Editorial Team. "Tree Value Calculator — CTLA Trunk Formula Method." TG we-Calculate. 2026. https://we-calculate.com/calculator/tree-value-calculator.
TG we-Calculate Editorial Team, "Tree Value Calculator — CTLA Trunk Formula Method," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/tree-value-calculator
@misc{wecalculate_tree_value_calculator, title = {Tree Value Calculator — CTLA Trunk Formula Method}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/tree-value-calculator}}, year = {2026}, note = {TG we-Calculate} }
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