By Paul Prill

In the early 1920s, when Rogers Caldwell and his wife, Margaret Trousdale, built Brentwood Hall on their 207 acre property, now the home of the Ellington Agricultural Center, one of the first trees they bought and planted was the Sawtooth Oak (Quercus acutissima) which still stands in our arboretum. That tree could not have been there when they built the house, because it was first introduced in the United States in 1925, an import from Asian countries. Sawtooth Oak was brought to the U. S. because it was a fast growing oak, reaching a height between 80 and 100 feet, and because it produced an early crop of acorns, food for the turkey and deer, which in turn were food for hunters. It is now listed as an invasive plant from Florida to New England and from the Atlantic Ocean to Texas. Its saplings grow so quickly that it outcompetes other oaks, in some cases producing a monoculture. Unlike native oaks, Sawtooth Oak does not support insect life, and its acorns are deficient in many of the nutrients in the acorns of native oaks. Nevertheless, the Caldwells did what we still do today, see a new plant which has useful features and put it in the ground, without knowing its ecological impact. The estimated age of our tree is 100 years old.

If you see a large tree with five deliberately damaged vines growing up it, you’ve found what is probably the oldest tree at the arboretum. The Black Walnut (Juglans nigra) doesn’t reach its full height (70-80 feet) until it is at least 150 years old, and it can then live another 100 years before it dies. The vines were winter creeper (Euonymous fortunei), and based on the sections we cut out, they had been growing on the tree for at least 30-40 years. Had they not been removed, those vines would have broken the tree in the recent ice storm. Black Walnuts, as most of us have known since our youth, kill most any other plant growing in their root zone. They produce a chemical, juglone, which acts as a natural herbicide, suppressing growth and causing plants to wilt. Even after a tree is removed, the soil can remain toxic to new growth for years. Black Walnut trees serve as a host plant to over 100 species of butterfly and moth larvae, including the caterpillars of the Luna moth and the Polyphemus moth. The nuts supply nutrient-dense food to squirrels, mice, foxes, and woodpeckers, and the Eastern Screech Owl often uses black walnut trees for a nesting site.