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 registry is updated yearly and published every December. Currently there are close to 100 champion and co-champion trees contained in the list.
Champion Trees of Oklahoma - 2014 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
Historic Oklahoma Champion Registries