Stalking the Japanese Knotweed and Other Scourges
Invasive plants are everywhere. But that doesn’t make every unpopular plant—that dandelion in your lawn, for instance—an invasive, said Christopher Mattrick, the botanist for the White Mountain National Forest’s Botany and Invasive Species program and a 1992 ES graduate.
Mattrick, who spoke at AUNE’s Spring Speaker Series on April 14, monitors rare and invasive species in the White Mountain National Forest, as well as a few insect species. To be defined as “invasive,” the plant must be non-native and located in a minimally managed area on which it has a negative impact. “Poison ivy, for instance, is not an invasive because it’s native,” Mattrick said.
Much of Mattrick’s job is making sure that projects in the White Mountain National Forest such as trail maintenance or bridge and road repair don’t undermine rare plant species. But an invasive plant infestation can do quite a bit of harm to rare plants and the forest ecosystem as a whole. It can muscle out other species. It can interrupt tree regeneration, alter soil chemistry, be a fire hazard, and open the way to other damaging organisms. For example: When the city of Worcester, Massachusetts, planted the invasive Norway maple to replace trees lost in the Hurricane of 1938, it allowed the current invasion of Asian longhorned beetle, which loves to feed on Norway maple.
While the heavily forested White Mountains have few invasives, there are some species that give Mattrick fits. These include glossy buckthorn, Oriental bittersweet, Japanese knotweed, and multiflora rose, whose wicked thorns may make it the nastiest invasive of all.
Getting the upper hand
If you want to get rid of an invasive plant, three methods are open to you: mechanical, chemical, or biological control, Mattrick said.
Early detection is the key to any successful containment. But chemical control—the use of herbicides—is by far the most effective. Mechanical means, such as digging up or cutting down plants, are difficult and may end up spreading the plant farther. Biological controls are being studied but, except for a few successes such as a beetle that can control purple loosestrife, are not yet far enough along in development to be useful. And who can say whether, down the road, the insects won’t develop an appetite for plants other than the targeted invasive?
There are about three thousand plant species that grow outside cultivation in New England, and of those about one thousand are non-native, according to Mattrick. But most of those one thousand species are simple weeds; only about one hundred or so are considered invasive. Yet about three million acres of habitat are lost to invasive species every year in the United States—about three times the size of Delaware. Invasive plants alone cost the country $34.7 billion annually, he said.
Protecting special places
The problem seems almost too big to tackle. “So it’s less about getting rid of what we don’t want than it is about protecting what we do want—special places that are important to us, a natural area or a rare species,” Mattrick said. “Those should be the reasons we work on invasive plant control.”
For more information on invasive plants, see the Invasive Plant Atlas of New England, the Center for Invasive Species and Ecosystem Health, Weeds Gone Wild, and the U.S. Forest Service’s Invasive Species Program.
The next Speaker Series event
The final event in the Spring Speaker Series is scheduled for Thursday, May 19, at 7 p.m. in the Community Room. is a panel discussion with
David Macy, (OM ’00,) resident director, MacDowell Colony; Lenny Matczynski, executive and artistic director, Apple Hill Center for Chamber Music; and Aaron Wiederspahn, executive director, The Starving Artist.
It is free and open to the public. For more information, please contact Sean Wiley email@example.com