Audubon uses grant to clear Falmouth property of invasive trees, plants
FALMOUTH — Visitors who frequent the Maine Audubon Center at Gilsland Farm may notice some significant changes to the amount and variety of vegetation.
The center recently received a $22,000 federal grant through the Department of Agriculture to clear the 65-acre property of invasive species. Payable over the next five years, the grant will enable workers to remove the growth and to revisit cleared areas to ensure they remain free of the menacing plants.
An invasive plant is one not native to where it is growing. But not all non-native plants are invasive. To be invasive, it must also have the potential of harming the environment or the economy or be harmful to human health. Some invasives become established because people use them in landscaping for their attractive flowers or foliage. Others have been introduced to try to solve a specific problem, such as erosion. Still others are established accidentally.
Due to their aggressive growth and lack of natural predators, once they take root, invasives can crowd out native species, altering animal habitat and food sources,Gilsland Farm Assistant Property Manager Bob Bittenbender said Tuesday. And they can spread to surrounding areas by their vigorous growth and from birds that ingest their seeds and deposit them in new places, he said. At the same time, the birds – and even insects that are an important food source to birds – do not receive proper nutrition from the invasives because they lack the right enzymes to digest them properly, he said.
On the Audubon property, Bittenbender said there are nearly a dozen invasives: purple loosestrife, oriental bittersweet, American bamboo, burning bush, Norway maple, autumn olive, Japanese barberry, glossy buckthorn, bush honeysuckle and garlic mustard. Some of these are still sold in nurseries and routinely used as landscape plantings for homes and businesses.
"It's because we haven't gotten together on this problem," Bittenbender said.
People still ask for shrubs like burning bush for its brilliant fall color, but there are good substitutes, he said, such as low- and high-bush blueberries, as well as newer hybrids that grow in between.
A commonly used tree, the Norway maple, is another invasive that staff and volunteers are trying to eliminate from the property. In the past few days, they have cut down 90 Norway maples of various sizes, which will allow more light to reach desirable trees like the sugar maples.
"One thing we're trying to do is to stay on the high road – we have some other Norway maples that are nice looking, but we have to take them out, too," he said.
Bittenbender said they chipped many of the smaller trees and will use the logs from others as firewood. Much of the brush is being piled and left as wildlife habitat, specifically for squirrels and some birds, including the red-tailed hawk that have been plentiful this year. Some of the logs will be left on the ground as homes for insects.
As they cut, they do use some chemicals to prevent regrowth.
"We are doing a method called cut and dab," he said. "We cut the plant off and dab the cambium layer with glyphosate herbicide. What that does is trans-locates in the plant and kills the roots. If you just cut them off, you think you're done with it, but you're not."
He said the center is "very selective" with the chemical's use.
Other invasives will be kept in check through repeated "bush-hogging" of the fields or ripping them out by hand, Bittenbender said.
The center hopes the project will be a demonstration of the importance of removing invasive species and individual responsibility to be educated and avoid planting them. And Bittenbender said he hopes to encourage dialog that could lead to one common policy for Maine and surrounding states that would make it illegal to sell invasive species, as it already is in New Hampshire.
"It's an educational process – invasive species are bad, it's not that we're out to get somebody," he said. "We need to have this discussion; we need to be talking about what's being done in other states."
Peggy Roberts can be reached at 781-3661 ext. 125 or firstname.lastname@example.org.