Norfolk Attacks Invaders

By Shelley Harms
Norfolkians know we have a special, mostly unspoiled hometown and, having lost our chestnuts and elms to foreign pathogens, we know the threat posed by invasive species. Lately, many of us have been waging an all-out assault to remove the invasives that are trying to take over our landscape, and to keep out the ones that may be storming our barricades.
Hemlock woolly adelgid is a tiny insect, originally from Japan, that kills hemlocks. It has spread rapidly through forests from Georgia to Maine. Since 2001, Great Mountain Forest has hosted research on these pests by Dr. Carole Cheah of the Connecticut Agricultural Experiment Station. When the telltale white cocoons were spotted at Doolittle Lake, the Doolittle Lake Company consulted with Dr. Cheah, and combated the relatively minor infestation by cutting off and disposing of the branches hosting the cocoons.
Zebra mussels have been reported in the Twin Lakes in Salisbury. Native to Russia, these little bivalves attach themselves to larger, native mussels and kill them, eliminating native mussels from many North American lakes. They are carried from lake to lake as unseen passengers on boats. To keep them out of Norfolk, the Board of Selectmen is considering placing restrictions on what boats can be used at the town beach at Tobey Pond.
Asian long-horned beetles have reached Worcester, Massachusetts. Native to China, this beetle kills maple trees and other deciduous hardwoods. The beetles travel in wood and on vehicles. In order to prevent introduction of these and other pests, the Great Mountain Forest is careful to use only one local sawmill, and carefully monitors equipment and trucks that enter the forest. The Connecticut Department of Environmental Protection (DEP) is asking residents to use local firewood, and report to them if any of these large, spotted beetles are seen in Connecticut.
Escaped ornamental shrubs and trees are spreading along Norfolk’s roadsides and in our forests. These plants, including Japanese barberry, Norway maple, multiflora rose, winged euonymus (“burning bush”), Asian bittersweet, common and glossy buckthorn, Japanese knotweed and bush honeysuckle, were originally planted on purpose as ornamentals. They “escape” when their seeds blow in the wind, are carried by water, or are eaten by birds and “planted” elsewhere. These plants out-compete native plants for nutrients, light and moisture, deprive wildlife of their food sources and harm biodiversity. Some, like barberry and multiflora rose, have thorns that make it painful to walk through the forest. Japanese barberry has even been linked to increases in Lyme-disease-bearing ticks. Incredibly, Connecticut still allows several of these plants to be sold by nurseries.
The Norfolk Land Trust is working to remove these rapidly-spreading shrubs from its preserves. In several work parties this fall, the Land Trust has tackled barberry by pulling it up, and buckthorn and honeysuckle by cutting the stems and applying weed killer directly to the cut edges. Great Mountain Forest has done the same, and also plans “prescribed burns” for the near future to rid the forest of large infestations. In conjunction with work on the path leading up to Town Hall, the town plans to remove an infestation of Norway maples.
The Norfolk Conservation Commission has been addressing the sources of these infestations: ornamental plantings. Last spring, the commission removed Japanese barberry and winged euonymus from the front of Town Hall, and replaced them with native shrubs. In response to increased awareness of the invasive nature of these plants, the Battell-Stoeckel Estate removed several large barberry plants from along the zigzag fence on Mountain Road, and the National Iron Bank replaced its barberry hedge with a non-invasive alternative. The town road crew, which had been accustomed to trimming large barberries at a street corner to improve sightlines, this year removed them altogether at the landowner’s request. Next spring, the commission plans a “plant exchange” where residents can receive a free native ornamental if they remove an invasive ornamental from their yards.
Garlic mustard will pop up again next spring. The Conservation Commission plans to repeat its garlic mustard awareness campaign, encouraging residents to pull it up, bag it and dispose of it, and offering a free garlic mustard cookbook to anyone who brings in a bag of the stuff. Many residents, including the Doolittle Lake Company, are vigilant in pulling garlic mustard every year. Goutweed, purple loosestrife, phragmites, and ragged robin are also spreading rapidly in Norfolk. Aton Forest has tried to control phragmites by cutting it, and one landowner has hired landscapers to go into his swamp in waders and pull out the phragmites manually. At Great Mountain Forest, great care is taken in what gravel can be brought in for the private roads, because of the threat of bringing in seeds of invasive plants. The town road crew is on the lookout for two additional, very invasive plants that, thus far, have not reached Norfolk, mile-a-minute vine and giant hogweed.
It can be expensive to control and eradicate invasive species. In the Mississippi River, the federal government built a high-tech barrier to keep Asian carp out of the Great Lakes. Closer to home, in Winsted, the Highland Lake Watershed Association and the DEP close the lake for a day every year to apply herbicide to control Eurasian milfoil. In Worcester, Massachusetts, the state conducted wholesale removal of trees infested with the Asian longhorn beetle and imposed a quarantine on wood products from the town.
Invasive species are a big deal. They kill or crowd out native species and alter entire ecosystems, and they are costly to combat. The more we are aware of the threat, the more we can all do to prevent future invasions and remove those invasives that are already here.