Idaho Big Tree Program

The Idaho Big Tree Program is part of a national program to locate, measure and recognize the largest individual tree of each species in Idaho. The nominator(s) and owner(s) are recognized with a certificate, and the owners are encouraged to help protect the tree.

Most states, including Idaho, keep records of state champion trees and forward contenders to the national program. Some cities, such as Boise and Lewiston, Idaho, also keep local records, and occasionally counties or other organizational units do the same. Lewiston, Coeur d’ Alene, Boise, and other communities also recognize and promote historically significant trees.

What is the definition of a tree?

A tree is defined as vegetation with a woody stem at least 3 inches diameter at breast height, or 9.4 inches in circumference, and at least 13 feet tall. With these specifications, Idaho’s smallest champion tree is a western dogwood measured about 16 years ago along the Selway River. At 30 total points, this tree, if still alive, would probably still be the smallest current champion if it were re-measured today. Many of our state and champion trees need to be re-measured and also determined to be still living. However, some long-term champions are in remote locations, such as the record whitebark pine 14 miles into the Sawtooth Wilderness.

How do I know if I have a champion tree?

Champion trees are based on a point system. One point is recorded for each foot of height and for each inch of circumference. Circumference is measured at breast height, defined as 4 ½ feet above the average ground level. The final component of the point system is the average crown width, with ¼ point for each foot of crown.

How do I find out where the big trees are?

The National Register of Big Trees lists all the U.S. champions for the nation-wide program with coordinators in each of the 50 states. Begun in 1940, the nearly 60 year-old program relies on volunteers to hunt down, measure and nominate state and national champion trees. The Idaho Big Tree list will provide you with information on Idaho state champion big trees.

Who do I call if I have questions?

Dr. Ron Mahoney, Emeritus Professor, is the current Idaho Big Tree Director. He can be reached at rmahoney@uidaho.edu.

Current National Champions in Idaho

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• Engelmann spruce (Picea engelmannii) — 486 points; Big Spruce Creek, Boise Co., USDA Forest Service, Lowman Ranger District; 2005.
• Whitebark pine (Pinus albicaulis) — 340 points; Imogene Lk., Custer Co., Sawtooth N.R.A.; 2007.
• Rocky mtn. lodgepole pine (Pinus contorta var. latifolia) — 298 points; Box Ck., Valley Co., IDL; 2008.
• Yellow willow (Salix lutea) — 53 points; Lemhi R., near Leadore, Lemhi Co., Private; 1985.