By Sam Quattrocchi
In 1953, a vegetation management research project was initiated — State Game Lands 33 Research and Demonstration Project (SGL 33). While intended to last just five years, the study has now been underway for more than 55 years. The treatment history, methods and findings are all aspects that have been presented in this magazine (most recently for the 50th anniversary of the project — see June 2003 Arbor Age, page 8). The SGL 33 Research and Demonstration Project continues to provide an invaluable source of information for an understanding of the response of plant and animal communities to rights-of-way maintenance practices.
Dr. Richard Yahner, professor of wildlife conservation at Penn State University, is the lead researcher of the project and takes pride in the ongoing study. “Ecology is always evolving, and we must do our best to keep up with it,” he said. “We need to constantly look at these areas to see if things are changing or if they haven’t changed.”
The project land is split into multiple sections where the effects of different integrated vegetation management practices are studied, including hand cutting, low-volume basal spray, foliage spray, stem-foliage spray, mowing, and mowing plus herbicide.
However, one method that is practiced along the entire research area is the wire–border zone method, which was implemented in 1982. The wire zone is the area directly beneath the power line, plus 10 feet on each side. Maintaining a community of grasses, forbs and low-growing shrubs is the goal in a wire zone area. In the border zone — an area 50 feet to each side of the wire zone — low- to medium-sized shrubs and low trees are encouraged, to transition into the natural forest. The wire–border zone method of maintaining utility rights-of-way has continued to be a cornerstone of the research project, and the study shows that wildlife habitat benefits from it.
Recent project findings
According to Yahner, small mammals are key components in any ecosystem. “Small mammals have many benefits in a natural ecosystem. They are an important element in the food chain as they are prey for hawks, foxes and owls, but they are major predators on insects and tree seeds.”
When herbicides eliminate tall-growing trees, the resulting shrubs, grasses and wildflowers thrive and supply food and shelter not found in the denser forests. Plant and animal communities under the wires also serve as unknowing helpers to resist the invasion of unwanted woody plants through plant competition and animal feeding behaviors.
As a follow-up to a two-year study of small mammals conducted in 1989-1990, a 2004-2005 study was conducted along SGL 33. The study found that one of the most important cover types to small mammals was forb-grass, which was established through an integrated vegetation management program using mowing plus herbicide applications.
The same study also found that forest cover types have fewer mammal species than are found under the right-of-way, which agrees with previous findings. “Small mammal diversity would be expected to be greater on the right-of-way with heterogeneous vegetation compared with the more homogeneous forest areas,” Yahner explained.
To look further into the heterogeneous aspect of the right-of-way, a study was conducted at the Green Lane Research and Demonstration Area — a sister research plot modeled after the SGL 33 grounds that is located in Southeastern Pennsylvania. From 2005-2006, 114 vascular plant species were observed in the treatment units. The total number of species per unit ranged from 46 species in hand-cut areas to 57 in stem-foliage areas, where specialty herbicides are mixed with a drift control agent and applied to the foliage and stem of target brush.
“These diverse areas attest, in part, to the effectiveness of integrated vegetation management to control unwanted species,” said Yahner. “And the preservation of desirable plants is equally important as controlling pest plants.” Studies by Yahner and his team on birds, reptiles, amphibians and butterflies at SGL 33 and Green Lane have confirmed the importance of proper right-of-way management to benefit the wildlife.
The project cooperators acknowledge that similar projects need to be established in different geographical regions and different ecosystems to help fine tune best practices. To help expand the scope of the project, a new demonstration plot was set up in 2007 — the Lake County Research and Demonstration Project in Lake County, Ill. State Game Lands 33 will surely serve as a baseline and model for the research.
“Before beginning any maintenance at the Lake County site, we will monitor breeding bird populations and vegetation,” said Yahner. “The intent of this long-term project is to establish a research and demonstration area comparable to two sites in Pennsylvania.”
With the expansive utility grid in the United States, not to mention highways, railroads, pipelines and other rights-of-way, there is a vast amount of land on which vegetation management must be performed. The work being done on SGL 33 and its sister sites can help do that in the most efficient possible way.
For more information, visit www.vegetationmgmt.com
Sam Quattrocchi is an ISA-certified vegetation manager and herbicide trainer who has worked with Dow AgroSciences for more than 27 years. He can be reached via e-mail at email@example.com