Our three-part webinar series, Measurement Tools & Techniques, introduces veteran and aspiring big tree hunters and tree-tech enthusiasts to the latest measuring guidelines from the National Big Tree Program. Produced with coordinated with Laser Technology, Inc. (LTI), each webinar focuses on one component of the equation used to crown a national champion tree: crown spread, circumference and height.

In 2013, American Forests assembled the Measuring Guidelines Working Group to update the current measuring guidelines and establish techniques everyone can use to minimize errors when nominating national contenders. Part of the ongoing effort to elevate the scientific foundation of the program is to equip state programs with the tools necessary to measure trees accurately and consistently. This webinar series highlights changes to American Forests’ measuring guidelines and sheds light on new techniques that will help participants of all skill levels when nominating and verifying champion trees.


Measurement Tools & Techniques Part 1: Crown Spread

Crown spread is often the first sign of a tree’s size. A tree’s canopy may be columnar, irregular, shaped like a cone or wide-spreading to shade an entire yard. When measuring the size of a tree, the longest and shortest extents of the canopy are used to measure average crown spread independent of the trunk position.

Laser rangefinders and clinometers can be used to measure the crown spread of tree, especially trees with high canopies. This webinar will cover the two-diameter method, spoke method and common obstacles when measuring crown spread.



Measurement Tools & Techniques Part 2: Circumference

In forestry, the girth of a tree is measured as diameter breast height (DBH), 4.5 feet above ground level. Trees vary in shape and size and grow in very different environments, often making it difficult to accurately measure the girth of a tree. One of the most common challenges big tree hunters face is the multiple-stemmed tree. How can you determine whether you are measuring a single tree if the tree has multiple trunks and forks below DBH? In each scenario, a judgment call must be made by the person measuring the tree.

In this webinar, you will learn how to measure the girth of a tree on a flat surface, a tree on sloping ground and a tree that leans. This webinar will also go over various considerations and tests of form, such as bark inclusion or pith, when determining if you are measuring a single tree or multiple trees.


Measurement Tools & Techniques Part 3: Height

One aspect of a tree’s growth that can be hard to measure is tree height. National champion trees may be 30 feet tall or 300 feet tall. From the red maple in your backyard to the eastern white pine in an old-growth forest, this webinar series will show you the most effective techniques to accurately measure the height of trees for all skill levels.

By using triangulation you can measure the height of a tree using a ruler, clinometer or laser rangefinder. In this webinar, you will learn how to use trigonometry to measure the height of trees and the best tools for each method. The webinar will cover the stick method, tangent method and sine method of measuring height.