For each nomination American Forests needs the following information:

1. Correct name of the species or variety (only U.S. native and naturalized species are eligible). If you need help with identification, call your local Parks, Forest Service, or Extension office.
2. Circumference of the tree in inches at 4 1/2 feet above the ground. If there is a fork at this point, measure the smallest circumference below the fork. If it branches below 4 1/2 feet, measure the largest single stem at 4 1/2 feet.
3. Vertical height of the tree to the nearest foot. The most reliable tools for this purpose are an Abney hand level, a hypsometer, or a transit. Lacking those, you can use a straight stick. Hold the stick at its base vertically at arm's length, making sure its length above your hand equals the distance from your hand to your eye. Walk backward away from the tree, staying approximately level with the tree's base. Stop when the stick above your hand appears to be the same length as the tree. You should be sighting over your hand to the base of the tree and, without moving anything but your eye, sighting over the top of the stick to the top of the tree. Measure how far you are from the tree, and that measurement-in feet-is the tree's height.
4. Average diameter of the crown to the nearest foot. Measure the widest spread of the crown and the narrowest, then add them together and divide by two.
5. Location.
6. Date measured and by whom.
7. Name and address of owner.
8. Clear photograph with date taken.
9. Description of the tree's physical condition.
10. Name and address of nominator.

Send to: National Register of Big Trees, American Forests, P.O. Box 2000, Washington, DC 20013.

Eligible species

To be eligible for listing in the National Register of Big Trees, a species must be recognized as native or naturalized in the continental United States, including Alaska but not Hawaii. (Species found only in Hawaii are not included.) Hybrids and minor varieties are excluded. There are 826 eligible species and varieties: 747 native and 79 naturalized. To determine eligibility, American Forests uses Elbert L. Little Jr.'s Checklist of United States Trees (Native and Naturalized), published in 1979 as U.S. Department of Agriculture Agricultural Handbook 541.

Definitions of Trees

As defined in the Checklist, trees are woody plants having one erect perennial stem or trunk at least 9 1/2 inches in circumference (3 inches in diameter) at 4 1/2 feet above the ground (breast height), a definitely formed crown of foliage, and a height of at least 13 feet. In contrast, shrubs are small woody plants, usually with several perennial stems branching at the base.

• Native tree species (also called indigenous) are wild and grew naturally or spontaneously in the undisturbed forest vegetation before the arrival of Columbus or other Europeans.
• Introduced tree species have been brought into the United States. A naturalized tree is an introduced species that has become common and established itself as though wild, reproducing naturally and spreading. Species accepted as naturalized are designated in the Register by the symbol (?).

How Trees Are Compared

To find a tree's total points, American Forests uses the following calculation:
Trunk circumference (in inches) + Height (in feet) + 1/4 of its average crown spread (in feet) = Total points o A nominee will replace a registered champion if it has more points. When two trees have scores that fall within 5 points of each other, they are listed as co-champions.

- The Editors