GROTON — When the Pines heard that a lot overlooking Gibbet Hill in Groton was for sale, they jumped at the prospect of a beautiful view of cows and lush flora. When they went to visit the lot, however, the old farm ambience was tainted by an expansive growth of trees blocking their view. Bob Pine, assuming these trees were cherries, thought that environmental regulations would prevent him from clearing them. He and his wife passed on the opportunity to buy the lot.
A few months later, however, the house across the street was partially demolished leaving a 1835 farmhouse that Pine had interest in buying. He visited the plot again and on further inspection realized the obstructive trees were not in fact cherries. They were buckthorn, an invasive species tormenting local wildlife.
An invasive species is a plant or animal that is not native to an ecosystem and causes economic or environmental harm to it. Most invasives in the United States were brought here intentionally or unintentionally by humans. Buckthorn, for example, was likely brought to Massachusetts in the horticultural trade from Asia and Europe, according to Mass Audubon. It disrupts native wildlife by crowding other plants out and altering soil quality, which in turn reduces safe nesting habitat and food sources for certain animals.
Pine could not only legally clear these trees to open up the view on his lot, but in doing so, he could play an important role in preserving native species. Pine, a member of the Groton Conservation Trust, bought the lot, and for the past 15 years he has been fighting invasives species on it. Not only does he clear the buckthorn on his property, but he also tackles other invasives such as bittersweet, a vine that wraps around native trees. Pine once had to cut down three trees together because they were choked in a nasty tangle of Bittersweet.
Invasives have been a problem in the U.S. at least as far back as colonization, according to Wayne Mezitt, chairperson of the Massachusetts Invasive Plant Advisory Group.
"I don't think it was recognized as a problem until recently," he said.
While it would be extremely difficult to identify when invasives first starting affecting ecosystems in the U.S., they are known to thrive in disturbed areas such as roadsides, cut meadows, and areas for timber harvesting, and thus have been spreading more rapidly within the last 200 years.
Pine thinks his parcel of land is so strongly invaded because it was not well maintained before he arrived.
In his words, "It's much easier to control invasives before they've become established."
Had a previous owner identified one buckthorn bush 20 years ago and pulled it then, there wouldn't be the hundreds of buckthorns he's found on his property now. As Stephen Hutchinson, Regional Director of Central and Western Sanctuaries for Mass Audubon, described, "early, detection, rapid response" or EDRR can be crucial in limiting the spread of invasives.
In addition, Pine attributed the issue to Groton's location between two forest biomes and climate change's effect on that balance. By Pine's estimate, the line separating the northern and southern biomes, or distinct tree communities, has shifted at least 20 to 30 miles to the north due to warming in Massachusetts. Scientists predict within the next century that this line could be pushed all the way to Canada due to increasing temperatures. As that line gets pushed, "that actually gives all invasives a leg up," Pine explained.
Japanese barberry, a spiny shrub with small oval leaves and red berries in the summer, is a favored home of ticks, and areas with infestations have approximately 60% more Lyme disease-carrying deer ticks, according to Groton's Invasive Species Committee (ISC). Another invasive species, the Emerald Ash Borer, invades ash trees, causing severe structural damage.
According to Massachusetts Department of Agricultural Resources, this damage increases the chance of downed limbs and wood debris, putting civilians in danger. This shiny, half-inch beetle also diminishes local ash tree populations, influencing lumber production and decreasing native biodiversity.
Various mechanical and chemical clearing strategies are employed across the country to address the spread of these harmful species. For example, Groton's ISC is preparing to fight Emerald Ash Borer this spring by injecting an approved pesticide into ash trees, the only currently effective treatment, according to chairman Brian Bettencourt.
While many of these clearing strategies are effective in the short term, the unfortunate truth is that invasives are very resilient. Pine found this to be true on his property. After his first big clearing project 15 years ago that lasted a week, he has had to keep clearing invasives several times a year: "I have to manage on an ongoing basis because once invasives have really come in and dominated an area, they keep dropping literally hundreds of thousands of seeds," he said.
While Groton's ISC and Pine are mainly involved in the clearing process, the Massachusetts Invasive Plant Advisory group is more concerned with prevention.
"I think what we've got to do is learn to recognize the plants that can be a threat and work earlier in the cycle to manage them," Mezitt said.
The advisory group tries to work with propagators and breeders to create sterile versions of invasive plants. Hutchinson is also hopeful about prevention with a focus on EDDR and the impact of "human assisted movement." He thinks it is important to inform the public of the many ways they may be inadvertently spreading invasives, such as through firewood transport from region to region.
When asked if the war against invasives is winnable, Mezitt replied, "Absolutely not! We're going to be confronted with unwanted plants coming in here forever." Bettencourt is a bit more optimistic: "War? Maybe it's unwinnable ... But many individual battles are winnable." And these battles can start right in your own backyard. "Just get out there and poke around," he urged. If you find any suspicious plants, he suggests you reference online sources such as the ISC's brochures, which feature identification tips and clearing strategies for widely spread invasives in the area. You can also reach out to the ISC or the MA Plant Advisory Group to help them document the threat if it is too hard for you to clear on your own.
Though fighting the battles in your backyard may seem inconsequential, Hutchinson assured they are part of the important process in rebalancing the local ecosystem: "individuals can make a difference in their own behaviors and in their own yards in terms of managing," he said. Bettencourt felt similarly, "A lot of times you'll find that if you get rid of things, the native plants in your yard or your little chunk of forest will do better, and it will be beautiful ... it's rewarding."
Cratsley is graduating from the Groton School Sunday. She is attending Georgetown University in the fall.