By Mark Aiken
Lands conserved through Vermont Land Trust easements are protected from the threats of development, misuse, and mismanagement. But there are other threats to productive farmland and forestland. One that is getting a lot of well-deserved attention is invasive plant species—that is, harmful non-native species that have been introduced to a new environment.
Most non-native species have a negligible impact; however, a small minority (about 8 percent, say experts), wreak immeasurable damages. Operating with no natural competitors or predators, marauders like Japanese barberry, honeysuckle, and garlic mustard get established and spread wildly, out-competing and suffocating native species. The results can be reduced native regeneration and lower woodlot quality in forestlands, decreased habitat for wildlife, and reduced availability and quality of hay in farmland and pastures.
Erica Zimmerman and her husband Kevin McCollister own a 60-acre, VLT-conserved , diversified farm in East Montpelier. “We noticed buckthorn when we toured the property with the previous owner six years ago,” Zimmerman said. “What we didn’t realize was how quickly it would spread.” The buckthorn invaded 20 acres of untended pastures that Zimmerman and McCollister intended to restore as pasture for grazing. “One hundred animals go through 60 acres pretty quickly,” said Zimmerman, “so we’d like to recover that.”
Unfortunately, buckthorn and other invasive species can be exceedingly difficult to remove, and, unchecked, they spread rapidly and widely. In Zimmerman and McCollister’s case, once they got more familiar with the tenacity of their adversary, it became clear that they were in for a long and difficult battle.
VLT stewardship staff report a heightened awareness and growing concern among landowners about invasive species. Some landowners know what they are looking for and have some idea of what to do. Others can identify invasive plants, but aren’t sure how to eradicate them. Still others don’t know what the invaders look like. “What all should know, though, is that it is not a hopeless cause,” said Regional Stewardship Manager Donna Foster of the Woodstock office.
The first thing landowners can do (if they haven’t already) is to educate themselves as to what invasive species are out there and what they look like. How can landowners get educated? “Give us a call,” said Kris Hammer, Regional Stewardship Manager for Central Vermont. Members of the VLT stewardship staff routinely walk sites with landowners. “Oftentimes, we identify species on our annual site visits,” Kris said. Staff will also discuss options for removal and disposal.
Different plants call for different approaches. Garlic mustard is easy to pull by hand. Buckthorn and larger barberry require a weed wrench, whereas Japanese knotweed, a perennial that is taking over many streambeds and wetlands, should be mowed down. Others (for example, knotweed growing on a riverbank where it is too difficult to mow or particularly dense honeysuckle) may be best controlled through the responsible use of appropriate herbicides. VLT’s stewardship staff is available to help landowners identify and demonstrate how to pull invasives, to discuss various options and resources available, and to even help connect with foresters and other experts.
The Internet is growing as a resource regarding invasive species. Both VLT and The Nature Conservancy websites offer extensive information about, and photographs of, invasive species most prevalent in Vermont as well as links to additional resources (see sidebar for addresses). Landowners can also attend workshops, talks, and nature walks to learn more. County foresters, The Nature Conservancy, VLT’s own Regional Stewardship Managers, and municipal and private organizations frequently run programs about invasive species. Landowners can consult their regional stewardship staff member, or check the VLT website for information about events in their area.
Once landowners identify whether they have a problem with invasives on their land, VLT forester Pieter van Loon cautions them to make a plan before running out to tackle the problem. “Research to figure out where invasive species are, how thick they are, and how big a problem they are, and then what methods are best to control them,” said Pieter. The severity of an infestation may help landowners determine the best approach for controlling it; if the infestation is heavy, landowners may decide to concentrate first on edges before working back to the epicenter where it is probably thicker. Said Pieter, landowners should also prioritize their goals for their land before attempting to eradicate invasives; the two go hand in hand.
In Erica Zimmerman’s case, for example, the objective isn’t simply to curb the buckthorn infestation. Rather, eradicating buckthorn is part of the broader goal of reclaiming untended pastures to improve her grazing operation. Another landowner may be interested in protecting a maple sugaring operation while still others may simply have sections of hardwood forest where they enjoy walking. Whatever the motivation, the hard truth is that the eradication of invasive species is not a “one and done” situation. “They have to keep at it,” said Pieter. “It takes a concerted multi-year effort.” Garlic mustard seeds, for example, remain viable for five years. The plants not only have to be pulled and removed, but follow-ups are required for years; otherwise previous efforts may be for naught.
Ridding invasive species is a daunting task, one that could seem overwhelming especially to those with large land tracts or heavy infestations. Two pamphlets can serve as allies for landowners: The Nature Conservancy’s Vermont Landowners’ Guide to Invasive Terrestrial Plant Management and the US Department of Agriculture’s Guide to Nonnative Invasive Plants (both available online). Meanwhile, Vermont’s Agency of Agriculture, Food and Markets (VAAFM) has accumulated a list of businesses that employ at least one person certified in the use of herbicides or pesticides to combat invasive plants and insects. This list isn’t available online, but landowners can contact Matthew Wood, the VAAFM Pesticide Certification and Training Coordinator.
Also of help to landowners is Sharon Plumb, Invasive Species Coordinator for The Nature Conservancy. Plumb serves on the Vermont Invasive and Exotic Plant Committee, a group that makes recommendations to the VAAFM concerning the Vermont Quarantine Rule, which bars the sale of certain plants. Their sights are currently set on burning bush and Japanese barberry, which—among others—are still sold in Vermont nurseries. She advises that the more creative landowners can be, the more resources become available to them. Host a breakfast for friends and relatives or a “plant-pulling party.” Make land available for a forestry workshop where people learn how to pull invasive species. Or, simply team up with neighbors to tackle each other’s properties. Anything is easier than going it alone. The problem of invasive species is statewide, said Plumb. “But people care about this issue, and every plot is a small manageable project.”
Even with teammates, battling invasive species doesn’t just take time and effort; it can be expensive too. Landowners may be eligible to receive federal funding through the U.S. Department of Agriculture’s Natural Resources Conservation Service; one component of grants issued through the Wildlife Habitat Incentive Program (WHIP) focuses on eradicating invasive species.
Vermont Land Trust’s stewardship staff doesn’t have the resources to help eradicate invasive species (although RSMs like Kris and Donna have certainly been seen pulling the weeds on site visits). But they help in other ways. Pieter and a dozen members of the VLT staff returned to the Nicoll property in Grand Isle for the second time in two years to get some firsthand experience ridding a hardwood stand of an invasive—in this case garlic mustard. “We could definitely see the results of last year’s effort,” Pieter said. “They were much better than I expected.” The property is also a test site; the staff tried several methods of eradication, some more labor-intensive than others. Pieter looks forward to sharing the results with landowners as they become available over the next couple of years.
Projects like the one at the Nicoll plot are especially valuable, because they help VLT staff understand, not just what landowners are up against, but what it’s like to meet the adversary head-on. Donna Foster, for example, attended a seminar on invasives last spring, and it made her look around: enormous autumn olive, barberry, multi-flora rose, bittersweet, and buckthorn plague the historic King Farm property, where her Woodstock office is located. “Now I’m interested in getting after it,” Donna said. “I can’t just go out and talk to landowners without trying to do something here!” Knowing that VLT staffers, as well as other landowners, are in the same boat may be some comfort. And, although invasives don’t just come in the form of plants (there are invasive insects and aquatic species too), landowners can access the expertise and resources to aid in their control effort. Take advantage of the resources available (including VLT’s stewardship staff) and work together. In so doing, landowners can make a stand defending Vermont’s lands.
Online Resources for Landowners
Vermont Land Trust’s links to invasives info and plant-by-plant fact sheets
The Nature Conservancy online invasives resources
US Department of Agriculture’s Guide to Nonnative Invasive Plants
Wildlife Habitat Incentive Program