American chestnut trees in Longenecker Horticultural Gardens (Photo: Susan Day)

Some of the most asked-about specimens in Longenecker Horticultural Gardens are four mature American chestnut trees (Castanea dentata), a species that is virtually extinct in its native range. The American chestnut was once the most abundant tree species in eastern U.S. forests, estimated to represent 40 to 50 percent of the canopy across its range. Unfortunately, this ended abruptly beginning in 1904 with the discovery of the exotic chestnut blight fungus (Cryphonectria parasitica) in the Bronx Zoo in New York. Over the next forty years, the blight would kill an estimated 3.5 billon trees and change eastern forest composition forever.

While not native to Wisconsin, the American chestnut is well adapted to our climate and able to thrive here, spatially isolated from the diseased trees of the east. Indeed, the largest known current population of American chestnuts in the world can be found on a farm by West Salem, where an early settler named Martin Hicks planted nine chestnut seedlings in 1885. These seedlings multiplied over time to an estimated 6,000 trees by the year 2000 on the 60-acre property known as Chestnut Hill. Researchers at first thought they had found a blight-resistant population and inadvertently exposed the stand to the fungus in 1987, most likely from spores brought on clothing from the east. Though the trees are cankered and stunted, most of them have been kept alive through treatment with experimental hypoviruses to control the fungus.

The Longenecker chestnuts were propagated from another Wisconsin chestnut stand near Galesville, planted by a young farmer named Oscar Ezra Beardsley. Oscar had come to the area in 1859 with his parents Bostwick and Mary and his nine siblings, two of whom died fighting in the Civil War. In 1876, Oscar purchased thirty-four bare-root chestnut trees from a nursery in New York State to start a nut orchard for his family. Years later, in 1952, a tool designer from La Crosse named Einar Lunde purchased the farm. When clearing brush near buildings he discovered the chestnut trees planted in rows. Almost immediately he began collecting and selling the chestnuts, harvesting 500 pounds in the first year.

Harry Tieman, a researcher at the United States Department of Agriculture Forest Products Lab in Madison, bought nuts from Einar in 1955. Shortly after, Harry gave some of the nuts to Bill Longenecker, then Arboretum director and curator of the horticultural area (now called Longenecker Horticultural Gardens). Bill planted the seeds in the Arboretum’s nursery area. Ed Hasselkus, a former student of Bill’s and his successor as garden curator, transplanted six chestnuts to the horticultural area in 1969 and 1970. Two were later removed due to space constraints. The four chestnut trees have flourished at the base of a glacial drumlin and represent some of the genetic diversity once seen in the eastern pre-blight forests, with slight differences in bloom time, nut size, and maturity. Blooming in late June and early July each year, the trees, covered with white catkins, are a sight to behold.

After Einar died in 1980, his son Phillip continued collecting and selling the nuts through 2009. Sadly, like the Hicks chestnuts, blight was inadvertently introduced into the stand between 2009 and 2010, infecting all the trees by 2013. To date the Longenecker chestnuts have avoided the disease, and hopefully that luck will continue well into the future.

—David Stevens, Ed Hasselkus Curator, Longenecker Horticultural Gardens