A gigantic American Elm on the Wallace Farm in Columbia was climbed recently in an effort to collect pollen before the buds open. The Nature Conservancy, in partnership with the U.S. Forest Service and other organizations, is working on a project to create trees resistant to Dutch elm disease, one of the most devastating tree ailment in U.S. history. The human bud collector, high in the tree, was dwarfed by the immense elm when this photo was taken earlier this month. (Courtesy Photo) (click for larger version)
March 23, 2016COLUMBIA – The American Elm (Ulmus americana) is a classic New England tree. For decades, the revered species has teetered near extinction as a result of Dutch elm disease (DED), which devastated elms across eastern North America.
In certain places and for reasons not completely understood, a few elms have survived. One on the Wallace Farm off Route 3 could be vitally important.
A program of the Nature Conservancy is seeking to gather buds from the few elms still remaining in an effort to create trees that can resist the devastation DED has caused.
Earlier this month, buds were gathered from the Wallace elm as part of the team effort between the Nature Conservancy, U.S. Forest Service, and other entities. Christian Marks discussed the science and detective work that might restore elms to their former glory as a major urban and rural tree throughout New England and beyond.
DED hit elms hard on multiple continents. Starting in Europe about 100 years ago, the bark beetles and fungus that cause DED came to the United States in the 1920s.
Reasons the American elm became a popular street tree were rapid growth and strong resistance to usual urban stressors, such as road salt and pollution. However, DED targeted the species across most of its range, leading to massive elm loses.
Isolation may be the reason why one Wallace elm survived. However, since a few other elms now gone stood nearby, the special survivor could have genetic resistance to DED. This is where Marks and his associates come in.
Marks has worked regionally and throughout the Connecticut River watershed on projects for the Nature Conservancy. He has a specialization in floodplain ecology, a logical link to attempts at bring back the elm, a tree common to floodplain forests prior to DED's deadly menace.
"There wasn't really any other species that could replace the American Elm in a floodplain," Marks said last week.
Forests in flood-prone areas along rivers are important for protecting water quality, controlling invasive species, and decreasing flood dangers to people, he added.
The loss of the elm hurts wildlife, as well. Another common floodplain tree, silver maple, lacks the sturdy branches of elms, Marks said. The elm is therefore a much better tree for nesting of bald eagles that live along the Connecticut.
Robert Young, who manages the 500 acres owned by Ruby Wallace, was happy to work with those seeking to revive the elm.
Over the years, Young recalls seeing the other elms on the parcel, but they lost the battle with DED. Of the group of elms on the land, including the one hardy survivor, Young said, "I'm 89, and they were here long before me."
Young said about 300 acres of the parcel is forested. The Wallace family has owned the property, now on the National Register of Historic Places, since 1785.
Pollen collected from places like the Wallace Farm can be used to grow DED-resistant elms. Marks said several cultivars have DED survival rates of 95 percent, but the project wants to go even higher so that nearly all new members of the species can avoid the sorry fate of so many American elms.
"You really need to climb the tree to get to the best branches," Marks said.
High parts of the tree receive the most sun, which creates conditions for more buds.
The team wanted to get to the trees before buds open.
Regarding the tree climbing and bud samples, Marks said, "We're done collecting for this year because we've had such an unusually warm winter."
Marks said that pollen gathered this year will lead to seedlings grown in a nursery, with field planting two years out.
When the young elms grow to an inch in diameter, each tree will be injected with DED to test disease resistance.
The project has some elms planted in Vermont's Northeast Kingdom now in order to test another factor of importance to tree survival in the region: cold tolerance.
In addition to improving floodplain management by planting elms along the Connecticut, Marks said the potential exists for elms to grace the streets of New England in large numbers once again.
Because of the project's scope and the large native range of American elm, Marks noted, the restoration work "requires the effort of multiple research groups." He mentioned teams in the Midwest and Canada also in the fight to bring back the elm.
Prior to becoming victims of DED, some elms in the United States grew to epic size. A tree known as "Herbie" in Maine was cut down in 2010. Herbie had a crown spread of 93 feet, was 110 feet tall, and had a circumference of more than 20 feet.