American Forests has been the keeper of the register since 1940 when forester Joseph Stearns said: "Let every tree lover, every forester, every lumberman rally ... to fight for the preservation of our biggest tree specimens." Since then, the register has turned into an institution with big tree coordinators in all 50 states and a group of big tree hunters always on the lookout for new champion trees.
Most states have big tree or champion tree programs and publish their own lists (I nominated the largest Alabama champion black willow and it still stands today). "The competition among states and big tree hunters often is fierce" according to American Forests. "Especially when the title for an official State Tree is held by a different state." These "hunters" are out to dethrone the national trees of record with their own nominations. They even remeasure existing ones to challenge any errors that might have been made.
These champion trees are measured mostly by foresters, rangers, or big tree hunters who submit nominations to the American Forests Register or the state big tree coordinators. A free brochure with rules for measuring and nominating trees is available from American Forests or through your state forester.
There are 826 native and naturalized species eligible for inclusion in the Big Tree Register. Eligible trees must be native or naturalized in the continental United States (including Alaska, but not Hawaii). They are listed in Check List of Native and Naturalized Trees of the United States, written by Dr. Elbert L. Little, Jr., former chief dendrologist of the U.S. Forest Service (see my review on his excellent tree check list).
The current list totals 751 champs and co-champs including 18 new ones. Newcomers include the co-champion Osage-orange trees in Virginia and Delaware, the Rocky Mountain Douglas fir in Texas, the Virginia pine in West Virginia, and the eastern white oak in Indiana. The Register is available in print from American Forests Magazine or National Register of Big Trees in html listed format.