Idaho Big Tree Program
The Idaho Big Tree Program is part of the American Forests National Big Tree program, whose mission is to locate, measure and recognize the largest individual tree of each species in the nation.
Start by going to the Idaho Registry of Champion Trees to see the latest measurements of all the current Idaho State Champion trees.
The National Big Tree program defines trees as:
- woody plants that have one erect perennial stem or trunk at least 9½ inches in circumference at 4½ feet above the ground (DBH)
- definitively formed crown of foliage
- height of at least 13 feet
Champion trees status is awarded using a point system.
- One point is recorded for each foot of height
- One point is recorded for each inch of circumference. Circumference is measured at the diameter at breast height 4 ½ feet above the average ground level (dbh)
- One-quarter point for each foot of average crown width
To calculate a tree’s total point value, American Forests uses the following equation:
- Trunk circumference (inches) + height (feet) + ¼ average crown spread (feet) = total points
When multiple candidates exist, the new “3 x 3” rule is employed, meaning co-champions are crowned using the following criteria:
- if the trees are under 100 points and within 3 points
- if the trees have more than 100 points and the differential is 3 percent of the total
Idaho Champion trees will retain their status until another nomination topples the reigning champ or the reigning champ dies.
Big tree nominations begin at the state level. The completed nomination packet is sent to the Idaho State Big Tree Program Director, who verifies the information and tallies the points. If the nominee has enough points to challenge the current national champ, records are then forwarded to the national level by the Idaho Director.
To get started, complete a Idaho Big Tree Nomination form. Measurements need to be verified in the field by a qualified forester. Please include GPS coordinates and photographs - they are required by both the state and national programs.
Email completed packet to:
- Yvonne Barkley, Idaho Big Tree Program Director
- Surface mail to:
Yvonne BarkleyIdaho Big Tree ProgramUniversity of Idaho875 Perimeter Dr., MS 1140Moscow, ID 83844-1140
Because of recent changes to the National Big Tree Program requiring champion trees to be remeasured every 10 years there are MANY tree species that have no current national champion. See Species without a Current Champ.