Mapping the Big Trees
Lantz, Gary, American Forests
A bulldozed beauty prompts a program aimed at protecting water quality by preserving arboreal treasures.
It was the diesel cough of a bulldozer headed for a potential state champion that motivated a group of New Jersey conservationists to look to the sky for help in saving forest giants threatened by development.
The Garden State's Big Tree Water Quality Project materialized when officials with the Mercer County Soil Conservation District heard of a huge old swamp chestnut oak facing developer-imposed demolition.
"We found out about the tree in the eleventh hour, actually the eleventh and a half hour, and we just couldn't come up with a way to save it," recalls conservation district director Bill Brash. "The tree had a tremendous amount of character, and it may have been a state champion for all we know."
The loss of the giant oak prompted the agency to seek a better way of identifying and protecting big trees threatened by development-a way that would cause a blip on the environmental radar screen long before the 'dozers began to billow black smoke.
"We needed a method that would let developers know these big trees were out there, where they were, and how they could avoid destroying them," Brash says. "After some research on our part we convinced the New Jersey Department of Environmental Protection that big tree protection could be fundable as a way to protect water quality under the Clean Water Act."
Soil conservation officials had plenty of data on hand to help them prove that trees provide the best available land cover for reducing rainfall runoff and preserving groundwater recharge, both critical factors in maintaining the "base flow" of any stream. And, since base flow is synonymous with stream health and water quality, it was clear that clean water is directly linked to the canopy cover provided by trees.
With a grant in hand to develop a demonstration project, the Mercer County crew looked to the sky for information that planners could access at the speed of light. Utilizing GPS/GIS satellite data, the group assembled a database that included all the big trees in a sprawling watershed district including portions of Hunterdon, Mercer, and Monmouth counties.
"We worked in tandem with the New Jersey Forest Service to put together a list of all state champion tree nominees found throughout the watershed, along with any trees of historical value," Brash says. The program is similar to AMERICAN FORESTS' National Register of Big Trees, which compiles records on the largest known of 826 native and naturalized species in the continential U.S. and Alaska.
The end result has been a web-based Big Tree information center that instantly identifies the location of each big tree in the watershed district, provides a photograph of the giant and includes all the vital statistics developers might require. Each New Jersey big tree in the study area also can be cross-referenced with a municipal tax map and a lot and block number.
The database, funded by taxpayer dollars and available to the public under New Jersey "right to know" laws, is open to anyone with the curiosity and a PC to access it. At the same time builders can check for the presence of big trees as part of, or even before, the development planning process.
The project benefits developers in several ways. "Most important from our point of view is the fact that they'll be protecting big trees and in turn, protecting local water quality," Brash says. "At the same time, identifying and saving big trees can reduce costs; the developer won't have to pay someone to clear that particular parcel of land or a crew to haul away the debris. And in the long run, we believe big tree zones will add to the real estate values of surrounding homes."
Since between 90 and 95 percent of all tree roots are in the upper 18 inches of the soil and generally extend to twice the diameter of the crown spread, the new program asks developers to "set aside a 'safe zone' distance that equals twice the crown diameter," Brash says. …