More than counting trees

Some visitors have asked what I am doing and why is my job important. Cultural landscapes are historically significant geographic areas that sustain great diversity of interactions between humans and the environment. They also protect traditional cultures, both living and those that have disappeared. Cultural landscapes include both cultural and natural resources. Each characteristic of the landscape must have integrity to the period of significance, which will vary in each site depending on the historic event, person, or place. For example, the period of significance of Fort Hunt goes from 1893, when it was acquired by the federal government as Coastal Defense fortification, to 1942 when the Civilian Conservation Camp stationed in the park. One of the characteristics to measure the integrity is the vegetation. Documenting the existing vegetation at the park can help with rehabilitation and restoration projects,  future planting plans, and evaluating the landscape’s overall condition.

Theodore Roosevelt Island

During this summer, I will be collecting data to create a tree inventory at Fort Hunt,  Arlington House, and Arlington Ridge Park. At Lyndon Baines Johnson (LBJ) Grove, I will be completing the original planting plan and verifying the conditions of the trees for a larger rehabilitation project. My job consists of identifying the tree, measuring the tree height, the canopy diameter, and the diameter of the trunk at breast height (DBH). To measure the DBH, I use a measuring tape at 4.5 feet above the ground (“breast height”). For 4 inch diameter trees, a caliper is used to measure the DBH at 6 inches above ground. For more than 4 inch diameter, the DBH is measured 12 inches from the ground until you can measure DBH at 4.5 feet below the first scaffolding branch! To measure the tree height, I use an instrument called a Tangent Height Gauge (THG). A clinometer can also be used to measure the tree height.

Taking the diameter at “breast height” (DBH) measurements on a Small-leaved linden tree at Arlington Ridge Park.

The data that I am collecting can be viewed live and can be edited by the Cultural Resources staff and employees with access to the Tree Inventory Group ArcGIS database at George Washington Memorial Parkway. ArcGIS is a cloud-based software used to map, analyze, and share data. In the map, I can add the scientific and common name, the location, the condition, and the measurements of each tree. I can also identify if it is a memorial tree, if it has any invasive species, or add notes that I find useful. To identify the trees, I use the existing planting plans from the 1940’s and the 1960’s, and a few book guides.

I really enjoy educating visitors about cultural landscapes and teaching them how to use the instruments. Most of the visitors are surprised by the characteristics and the importance of the cultural landscapes around the park. Listening to their feedback and watching their enthusiasm fills me with joy and reminds me every day the impact of my job.

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