UNC Libraries Digital Research
Search using this query type:

Search only these record types:



Advanced Search (Items only)

A Beautiful Death

Eric Geiger

 

            “What a pretty looking tree” I said pointing to a very tall tree with odd white patches all over its trunk in the distance.  This past summer I had landed an internship in Maryland along with my friend Ari from UNC; he was an experienced backpacker and I was just getting into the activity of putting my essential needs in a pack and carrying it all on my back for multiple days in the woods.  We decided to spend this particular weekend on part of the Appalachian Trail doing a quick, but hard two day trip that would have us walking in three different states.

            “It looks that way because it’s diseased; that tree is infected by a fungus and is slowly dying” he replied.

Elm Bark Beetle Galleries

Figure 1: These Elm Bark Beetle Galleries carry a distinctive mesmerizing feeding pattern.  However, it can be an indicator of an inevitable tree death.

            My ignorant observation gone wrong drove me to quick silence as I reflected on this tree’s fate.  I had spent most of my childhood, and adolescent years indoors often spending my spare time watching cartoons, playing video games, and wasting time on the internet; it was only in the past few years that I slowly came to appreciate and prefer the natural world that was found on the other side of the glare-inducing window.  Realizing that my main problem was simply a lack of education about the nearby woods I asked more about the sickness.  Ari had seen and learned about this particular disease up close and personal as it had particularly affected the Appalachian Mountains near his hometown.  He told me about the invasive insect species that would burrow into the tree’s bark to make its home while introducing a tree killing fungus and laying eggs so its offspring could grow up to do the same to many more trees.  I was saddened by a sense of helplessness over this system; I had learned in high school about the infestation of the cane toad in Australia and knew how an invasive species had the potential to devastate the biodiversity of an ecosystem.

Row of American Elms -  Fall

Figure 2: A walkway in the National Mall during Fall time lined with American Elms

            When I came back to UNC for the fall semester I found myself in the class English 266: Science and Literature.  I had learned about this class when searching for courses that would fulfill my remaining General Education requirements, but I signed up for the class due to a desire to learn more about the natural world around me.  One thing that stuck with me throughout the class was the very permanent impacts that humankind had made on its environment.  When reading Aldo Leopold’s A Sand County Almanac I found myself immensely saddened by the fate of the Passenger Pigeon whose great flocks would blot out the sun, one such flock was recorded to be over 300 miles long (6).  A similar feeling came over me while reading about the former reign of the Longleaf Pine and the end of it which came in part due to extensive clear cutting.  I then learned about Dutch Elm Disease and the way it had ravaged the American Elm tree.  Unlike the case of the Passenger Pigeon and the Longleaf Pine, the devastation of the American Elm was not due to overhunting or clear cutting; the harm to the American Elm was not deliberate.

Rows of American Elms - Winter

Figure 3: Same location as previous picture.  Even during the winter the American Elms form a fantasy-like canopy covering.

            The American Elm was a popular shade and ornamental tree and was planted closely in rows along streets.  The canopy the trees formed over roads was a wonderful sight indeed and was the pride of many city streets.  Perhaps the most famous instance of this is found in Washington D.C. where they still stand today all throughout the National Mall.  Other places have not been so lucky; one consequence of planting the Elm Trees so close together is the way Dutch Elm Disease was allowed to spread like wildfire and kill entire rows of trees at once.

Elm Bark Beetle

Figure 4: A smaller European Bark Beetle.  Among a few other species these are the main vectors of the fungus that causes DED.

            Although the fungus that causes the disease is thought to have its origins in Central Asia Dutch Elm Disease is named such because it was identified by a group of Dutch researchers after it started infecting trees in the Netherlands.  The fungus was most likely present in logs that were shipped to Europe and North America; while the trees of Central Asia were immune to the disease, insects such as the Elm Bark Beetle were able to spread the disease to the native and very susceptible trees of North America and Europe (4).  The disease causing fungus Ophiostoma novo-ulmi is able to enter a tree usually through the damage caused by the feeding patterns of Elm Bark Beetles which leaves the xylem exposed; the xylem is responsible for carrying water and nutrients throughout the tree.  Once the fungus enters through these passageways it is able to spread quickly and often results in the death of the tree.  These dead trees make good homes for Elm Bark Beetle eggs which after hatching are able to transmit the fatal disease to other nearby Elm trees (4).  Another method of transmission for this disease proved especially fatal to the Elms that were planted closely together in rows allowing the disease to spread through grafted roots.  Grafted roots occur when related tree species grow close enough together for the roots to cross over and fuse.  Once one American Elm in a row contracts the deadly disease it is able to spread astoundingly fast down the row (1).  In the city of Detroit many of the Elms were killed this way and altogether Michigan lost over 80% of its Elms (3).

Dead Elm

Figure 5: When a tree becomes infected with Dutch Elm Disease sometimes the best thing to do is to remove it.

            There have been many attempts at stopping the spread of this disease with varying degrees of success in different regions.  In Rachel Carson’s Silent Spring she cites two different approaches to containing the disease.  At the University of Illinois in Urbana, Illinois the disease made its first appearance in 1951.  The method of containment chosen by the university was by spraying insecticide.  Spraying started in 1953, and by 1959 after six years of spraying 86% of the University’s elm population had died (5).  The city of Toledo in Ohio took a different approach; after reviewing the effectiveness of spraying the Superintendent of Forestry decided against using insecticides and instead focused on removing infected elm trees before the disease was given a chance to spread.  In this approach of sanitation the trees would be cut and used for firewood before the beetle eggs inside them could hatch and spread (5).  Other cities such as used this method to achieve remarkable results including Syracuse who was able to put their rate of elm tree loss under 1% per year (5).  There have also been attempts at cultivating a disease resistant American Elm.  This is done through cross breeding with more durable exotic elm species.  The process is difficult and still ongoing as many of the disease resistant hybrids also lose the American Elm’s signature upright canopy spread that make it such a wonderful ornamental and shade tree (2).  

            As seen from the above efforts, the American people want to preserve the elm trees that once grew in incredible abundance.  Though it is easy to feel helpless as an individual in the face of such a devastating disease through active community participation and education we can work together to slow the spread of Dutch Elm Disease.  In UNC’s arboretum and on two of the Noble Grove walks around campus there are a few American Elms that stand proud.  With the proper care and maintenance these trees will be able to spread further through the campus, through North Carolina, and through the rest of North America where American Elm trees once stood in great numbers, tall, mighty, and magnificent.

 

Class of 2014

Mathematics

Apex, NC

Bibliography

1.  Haugen, Linda. "How to Identify and Manage Dutch Elm Disease." . United States Department of Agriculture, n.d. Web. 5 Dec 2013. <http://www.na.fs.fed.us/spfo/pubs/howtos/ht_ded/ht_ded.htm>.2. 

2.  Snover-Clift, Karen. "Dutch Elm Disease." Plant Disease Diagnostic Clinic. Cornell University, n.d. Web. 5 Dec 2013. <http://plantclinic.cornell.edu/factsheets/dutchelmdisease.pdf>.

3. Baulch, Vivian. "How Detroit Lost its Stately Elms." Detroit News [Detroit] 20 December 2001, n. pag. Web. 6 Dec. 2013. <http://blogs.detroitnews.com/history/2001/12/20/how-detroit-lost-its-stately-elms-8/>.

4.  Mannion, A. M. "Dutch elm disease." Encyclopedia of American Environmental History. Ed. Kathleen A. Brosnan. Vol. 2. New York: Facts on File, 2011. 418. Gale Virtual Reference Library. Web. 5 Dec. 2013.

5.  Carson, Rachel. Silent Spring. New York: Houghton Mifflin Company, 1962. 114-116. Print.

6.  Sullivan, Jerry. Hunting for Frogs on Elston, and Other Tales from Field & Street. Chicago: University of Chicago Press, 2004. 210-213. Print.