The Changing Role of Native Trees at the Civil War Defense Sites of Washington

by Deb Merriam

Abatis

Above: An example of an abatis. Below: David Lowe from the National Park Service identifying Civil War Defense earthworks

Last week our survey team visited Battery to the Left of Rock Creek and Fort DeRussy one of the largest Fort sites in the chain of Civil War Defenses. As we walked up a steep hill to the site of the Battery to the Left of Rock Creek we were surrounded by dense tree cover most notably native oaks and beeches. It was hard to imagine what this site would have looked like during the Civil War, completely denuded of trees. While surveying the scene from the top of the hill I remembered a reference  from the National Park Service Cultural Landscape Inventory written by a young Union soldier:

“It was an interesting sight to witness the simultaneous falling of a whole hillside of timber: the choppers would begin at the foot of the hill, the line extending for perhaps a mile, and cut only a part way through the tree, and in this way work up to the crest, leaving the top row so that a single blow would bring down the tree-then, when all was ready, the bugle would sound as the signal, and the last stroke of the axe be given, which brought down the top row: these following on those below would bring them down, and like the billow on the surface of the ocean, the forest would fall with a crash mighty like thunder.”

These trees became an integral part of the creation of the fort. They were used as abatis, a line of felled trees surrounding the fort their protruding branches sharpened as part of the defenses. Trees were used for roofs and walls and added to the earthworks for support.  After the war most of the trees that surrounded Washington had been decimated and wood was scarce, many of the forts were dismantled, advertisements called for bids on abatis, timber, lumber and other fort materials. The profits for selling wood and tools were over 15,000 dollars.

Today the urban forest is so thick we could barely see Military Road just 100 yards below the site.  As inexperienced identifiers of earthworks we walked right by the battery that was covered with thick layers of leaf litter, woody shrubs and huge beech trees. David Lowe, Park Service employee in the process of GIS mapping Washington’s Civil War Defenses earthworks, called us back to the site of the battery and identified the various earthworks and their functions. Soon we were reading the landscape for telltale signs of earthworks, large trenches, abrupt changes in topography and various pits.

Fort DeRussy earthworks protected by tree cover. Erosion caused by foot traffic.

Large stands of beeches grow directly out of the earthworks on every side, effectively hiding and protecting them at the same time. David explained that the best examples of preserved earthworks owe this protection to full forest cover. These are generally well protected from erosion by their thick leaf litter and thick vegetation, which intercepts rain as it falls toward the ground. The only damage  we noted was from foot traffic on the earthworks.  These native trees can also provide clues about the history of the site. As we walked along the trail we came to a huge overturned beech, the vast root system exposed. David scoured it for signs of the past. He explained that often artifacts from the sites are found in the roots of overturned trees. Native trees that were once an integral part of the Civil War Defenses of Washington now conserve and reveal details of their important legacy.