By Christopher Shields
Greenwich was known early on for the beautiful elm trees that lined many of its public streets and gracd numerous private yards and gardens. When Dutch Elm Disease reached the shores of North America in the 1930’s, however, it was the first municipality in Connecticut to suffer its devastating effects.
Dutch Elm Disease is caused by a fungus whose spores are carried by the elm bark beetle. Although the disease is also transmitted from tree to tree via root grafts, the beetle is often the cause of infection when it feeds on and resides in the branches of a tree. The disease damages and often kills because it interferes with the movement of water inside the tree.
Shipping crates that were composed of infected elm wood or lumber from infected trees may have transmitted the disease to the United States and Canada.
The Town of Greenwich began aggressive attempts to stop the spread of infection by identifying, removing and destroying diseased public trees. Efforts were made to educate residents about the disease so that they could address problem trees on private property in the same fashion. However, over a decade of this costly effort proved largely ineffective and hundreds of trees were destroyed each year.
When Joseph A. Dietrich became Tree Warden in 1945, he drew on his experience as a landscape architect and former Army engineer to develop a new approach. Dietrich knew that the insecticide DDT had been used very effectively during World War II to kill disease-carrying insects. After experimenting with different mixtures and application methods, he began using a mist blower to apply a solution of DDT to public trees twice a year. The rates of infection consistently declined and by 1956, less than 1% of Greenwich’s elm trees had the disease. The prevention/treatment methodology first developed and deployed in Greenwich gained the attention of communities across the United States and was soon widely emulated.
Concern about the environmental and health dangers posed by DDT began to emerge in the late 1960s and by 1972 its use in the United States ceased.
Current practices to prevent and treat Dutch Elm Disease include appropriate pruning, the application of approved insecticides and fungicides as well as the replacement of trees with disease-resistant elms.
The archives at the Greenwich Historical Society recently received a small collection of photographs and documents related to the Town of Greenwich’s effective efforts in dealing with Dutch Elm Disease. It also has a collection of Annual Reports of the Town of Greenwich that provide insight into the scope of the tree loss over the years.
The archives are open to the public on Wednesdays from 10 a.m. to 12:30 p.m. and 1 to 4 p.m.
Christopher Shields is the archivist at the Greenwich Historical Society, 39 Strickland Road, Cos Cob, CT 06807.