I have been thinking about elms lately. I recently ran across an article about elm trees in the Washington Post by Phil McCombs from 2001: “Once upon a time in America, great leafy high-arching cathedrals of elms lined the streets of villages and cities from the Atlantic to the Rockies, casting a deep cool shade upon life’s turmoil.”
Historically the American elm ranged roughly east of a line from southeast Saskatchewan to central Texas where is was generally a minor forest component. However, it was overwhelmingly the tree of choice in urban settings during the 1800’s and early 1900’s. It tolerated a wide range of environmental conditions, grew quickly, and had a long-life expectancy. Plus, it grew tall, with a crown, oh that crown! It was often described as a spreading fountain.
But all that changed around 1930 when Dutch elm disease, caused by a fungus, apparently hitched a ride on a ship from the Netherlands, headed to Ohio with a load of elm logs to be made into veneer. It is interesting to note that Dutch elm disease is not native to the Netherlands. It is probably Asian. But of course, the Dutch are forever associated with the disease.
The fungus attacks the water conducting tissues or xylem in the plant which eventually gets plugged up, thus stopping the flow of water and nutrients. The disease struck with a vengeance and spread rapidly, killing upwards of 90% of infected trees. The first case documented in North Dakota was during 1969 in Mandan.
There is occasionally some confusion as to just what actually causes the disease. Dutch elm disease is caused by a fungus, but the carrier or vector of the disease is the elm bark beetle. But it is interesting to note that much of the spread of the disease is not from the beetles, it is through natural root grafting. Many of the elms that graced the streets and boulevards around the country were connected underground by naturally occurring root grafts. Some of you certainly can remember the trees dying along the streets like toppling dominoes.
All is not lost however. A few elms continue to thrive, and some have estimated that a small recovery is occurring. We also can now inject the elms with a fungicide in 1-3-year intervals, but it is costly. Planting elms is generally not recommended, but there are also some resistant varieties have been developed, such as “Jefferson,” “Princeton,” and “Valley Forge.”
~Chuck Lura
