Big Tree Program finds balance between tree science, community engagement
The formula for measuring a champion tree is deceptively simple: add the trunk circumference (in inches) to a tree’s height (in feet) and one-quarter of the tree’s spread (in feet).
Many of the tools required for the job are probably in your basement (100-foot tape measure, plumb bob), and many of the rest (compass, GPS receiver, rangefinder) are easy to download onto a cellphone. Brush up on some geometry and lace on a pair hiking boots and you’re most of the way there.
This is as it should be, says College of Natural Resources and Environment Associate Professor Eric Wiseman, who coordinates the Virginia Big Tree Program, which celebrated the 50th anniversary this year.
“The central purpose of this program is to promote the conservation and preservation of these heritage trees and to raise the general public’s knowledge and literacy about forests,” said Wiseman, a faculty member in the Department of Forest Resources and Environmental Conservation who has led the program since 2013. “We want our research to be rigorous enough to be taken seriously, but we also want the process to be simple enough so that the general public can participate in the work.”
Virginia tree hunters have proven up to the challenge: according to the 2020 National Register of Champion Trees released by American Forests, the commonwealth has moved into first place among states in champion and co-champion trees, with 102 registered trees. And Virginia’s forests show remarkable diversity: the state’s 67 tree species champions rank second only behind Florida’s 77.
Wiseman said that while his contributions to the state’s big tree database, from combing through the national database to find eligible species to promoting contending nominees, has taken place behind the scenes, the hard work of finding and documenting big trees is accomplished by the outdoor enthusiasts and professionals who share their discoveries with him.
“I may be the point person who holds this project together,” he noted, “but our success wouldn’t be possible without all of the volunteers who search for trees as a hobby or as part of their profession, and the people who work in arboriculture or land management roles for state agencies or federal parks.”
American Forests’ efforts to document large trees dates back to 1940, but some states started tracking trees long before then. The project of measuring the maximum size and geographic distribution of trees was initially motivated by lumber industry considerations.
“You can see that history reflected in the formula we use to award points for champion trees,” Wiseman said. “We give a lot of points for the trunk of the tree, but the crown spread is significantly reduced in the formula. The reason for that is because back then, the value of a tree was measured by how much board footage the trunk contained.”
That priority is changing: the information provided by tree databases is now being used by scientists to research a range of new questions, from the spread of native and invasive tree species to questions about how tree growth can positively impact the environment through carbon sequestration.
“A lot of current interest is in the tree’s growth rate and how much leaf area it has,” Wiseman noted. “These are crucial metrics for ecosystem services in urban areas, because leaf area is important in filtering air pollution and intercepting storm water. And we’re increasingly interested in how much carbon can be stored in trees, which makes the scaffolding of branches and the crown spread an important consideration.”
While Virginia’s Big Tree Program allows people who are passionate about trees to contribute to a database of information, Wiseman hopes that the program can be a resource for bringing environmental education to young students.
“Looking for big trees involves geography, geometry, plant taxonomy, and biology, all integrated towards a specific challenge,” he said. “It’s a great way to get students to synthesize a lot of different cognitive skills while spending time in the outdoors.”
Individuals can access the Virginia Big Tree database online to find champion trees in their neighborhoods and favorite recreation areas. American Forests offers a free downloadable handbook on how to measure big trees.
Story by David Fleming