Oklahoma Forestry Services, in cooperation with the Oklahoma Forestry Association, maintains records on the largest specimens of many of Oklahoma's tree species. This list has been updated and published periodically since the early 1960's. The last publication was in 2000, but now the list is continuously updated, maintained, and displayed on the web. Currently there are more than 100 champion and co-champion trees contained in the list.
Champion Trees of Oklahoma - Registry
Eligible Species List
How to Measure a Champion Tree
Application Form - Nominating a Tree
Form for Use by Forester to Evaluate a Nominated Tree