Basic methodology descriptions can be found in i-Tree Landscape's references and the about i-Tree Design page.
The i-Tree Glossary is a good resources for those new to urban forestry. The information archive has detailed methodology documentation, notes, and links to technical papers.
Third-party use of the REST API has its own site and documention. Third-party use helps fund the service. Its use requires signed terms following our contract agreement. See the The Davey Tree Benefits Engine site for details.
International use is limited to locations where i-Tree Eco and associated secondary processing has been fully funded. For other locations, US national averages will be used as base data to compute tree benefits; using these estimates should indicate such.
The i-Tree Database site displays the i-Tree Eco supported locations.
To reiterate, only i-Tree Eco locations that have that secondary processing funded and completed are available in i-Tree Engine.
At this time, all international locations are of beta status. Critical results should have samples compared to i-Tree Eco before publishing.