Tree valuation methods compared: CAVAT and i-Tree Eco, what the sources say

This page reports what the official source says. It is not legal advice: ask the office named here. It describes two published ways of valuing trees, as their own sites and documents word them. It does not value any tree, and it does not cover the Helliwell system or the Guide for Plant Appraisal, because no public page for either was read for this page on October 8, 2026.

The two methods side by side

Point	CAVAT	i-Tree Eco
Who publishes it	The CAVAT Group, with its documents hosted by the London Tree Officers Association (LTOA)	The i-Tree suite of tools, which carries a notice that a change in USDA Forest Service policy has halted traditional funding
What it produces	A money value for an amenity tree, from a trunk formula adjusted for tree health and function	Reports on forest structure, environmental effects and value to communities, from field data on single trees, complete inventories or random plots
Inputs named by the source	Trunk cross-section, a Unit Value Factor, a Community Tree Index for the local population, and scored adjustments for the structure, crown and leaf cover	Field data plus local hourly air pollution and weather data
Where the source says it is used	By over half of UK local authorities, according to the LTOA page	Government agencies, consultants, nonprofits, universities and others, in the United States and other countries

How CAVAT describes itself

The LTOA says CAVAT, short for Capital Asset Value for Amenity Trees, was developed by Chris Neilan and the LTOA in 2008. It describes the method as a way of managing trees as public assets rather than liabilities, usable for a whole tree stock or for the value of a single tree. The page lists a Full Method and a Quick Method. The Full Method was updated in 2023 with a Guide for Practitioners and a survey spreadsheet. The page says the update added steps that judge how complete and how good the tree, its crown and its leaf cover are, to address the under-valuing of trees that are heavily managed, such as urban pollards.

The scored steps in the LTOA crib sheet

The LTOA crib sheet summarises steps 5 to 9 of the Full Method as scores. Primary structure completeness is scored from the extent of loss, whatever its cause, with four bands from more than 75 per cent complete down to between 1 and 25 per cent. Primary structure quality has four grades, excellent, good, fair and poor, which retain 100, 75, 50 and 25 per cent of value. Crown completeness compares actual height and spread with an expected optimum tree of the same species and stem diameter. Leaf cover completeness is based on the amount of foliage present at the time of assessment, in 20 per cent steps. Crown and leaf cover quality is adjusted in 25 per cent steps.

Where the Unit Value Factor comes from

The CAVAT Group document on the Unit Value Factor says it is the full cost of a newly planted tree per unit of trunk cross-sectional area. It is worked out from nursery trade prices of the top selling trees in the 12 to 14 cm size, with planting cost added. Nursery sales data are collected from suppliers each year and are anonymised in the workbook as Nursery A, Nursery B and so on. Where nursery data cannot be collected, the document says the previous factor is raised by the retail price index.

How i-Tree Eco describes itself

The i-Tree Eco page says it quantifies forest structure, environmental effects and value to communities. Its listed outputs include pollution removal, carbon storage, avoided run-off and building energy effects, plus species and leaf area summaries. It does not describe a score for the structure of one tree in the way the CAVAT crib sheet does. For how tree condition is judged, see tree risk assessment methods and how tree risk assessment works. For who writes valuation reports, see consulting arborist credentials.