Click on image to enlarge.

Title: Information Sheet, The Urban Forest of Reservoir Road, Washington, D.C.

Instructors' Note

A student in Forest Ecology (fall 2002) at Georgetown University (GU), Washington, D.C., produced this report as an individual class project which had a limit of about 20 hours. Goals of the projects included:

(1) learning about a relatively natural forest (Glover-Archbold Park which is adjacent to Georgetown University), the "open urban forest" of GU Campuses, and the "urban forest" in residential neighborhoods near GU.

(2) providing information about these subjects to interested parties via the Internet.

These are short projects that lay groundwork for further investigation in their respective areas. Therefore, these are pilot projects. To see all of the 2002 projects, please use the keyword FE2002R on this Website. Projects of future Forest Ecology students might continue lines of investigation of the 2002 projects.

E. M. Barrows and N. Bakkour, instructors

---

The Urban Forest of Reservoir Road, Washington, D.C.

Alexandra A. Herzlich
Department of Biology
Georgetown University
Forest Ecology 355, Fall 2002

Abstract

I surveyed the trees of Reservoir Road between 37th and 39th Streets in Washington, D.C.  The aim of this study is to ascertain which trees grow well in an urban forest under the specific conditions of the Washington, D.C., Area.  I mapped the locations of the trees, and recorded their species, heights, and health.

Introduction

When many people think of forests, they think of ones the country or rural areas in which many people live.  However, there are also urban forests all around us.  The trees planted along roadsides, our backyards, and on the university campuses, are parts of urban forests.  These trees play an integral part in human life and should be considered as important as the rainforests in Central America.

Urban forests consist of a different population of trees than do forests in a national park, for instance. Urban foresters must consider factors such as pollution, small soil beds, local climate, and economic stability when planning such a forest.  People, such as the urban planners of the Washingtion, D.C., Area  (WDCA) may sometimes overlook such problems when planting trees.  This can then lead to tree health problems and death, inconveniences caused by trees themselves, or both..

On Reservoir Road in Washington, D.C., between 37th and 39th Streets, there are five tree species in a two-block span.  Some of these trees were suffering because of where they were planted,  because of the recent drought in the WDCA, or both.  Some specimens looked very healthy. 

Urban forests offer many advantages to their environments.  The forests can reduce the air pollution, mitigate the greenhouse effect, conserve water, reduce soil erosion, save energy, modify the local climate, reduce noise pollution, and create help to increase wildlife diversity.  They can also improve human health by being recreation areas. 

Materials and Methods

I surveyed the trees Reservoir Road in early autumn when all of the trees still had foliage.  The tree species, height, diameter and condition were recorded. Also, I recorded the distances between the trees.

Results

There were 17 Acer saccharums (Sugar Maple), 1 Acer rubrum (Red Maple), 1 Ulmus americana (American Elm), 1 Maclura pomifera (Osage-orange), and 3 Robinia pseudoacacias (Black Locust) (Table 1, figure 1).  All trees were in relatively good health.  Most maples had leaf scorch.  The Ulmus americana did not show external symptoms of the Dutch Elm Disease, which has killed many American Elms in the WDCA.  The taller trees were Acer saccharum 5 and 12 and Robinia pseudoacacia 1. The tree with the largest diameter was Acer saccharum 5. Surprisingly the Robinia pseudoacacias did not have as large as trunk diameter in comparison to their heights. Robinia pseudoacacia 1 was covered in English Ivy; the Ivy continued up about 50 feet on this tree's trunk.  Many trees between 37th and 38th Streets (including Acer saccharum 3 and Robinia pseudoacacia 3) had Poison Ivy growing on their trunks.  The Acer saccharums 8, 9, 10, 13, 14, 15, 16, and 17 on the block between 38th and 39th Streets had a lot of leaf damage, possibly because these trees grew in an area between the street and a park. These street trees, including Ailanthus altissima, (Tree-of-heaven) and some Robinia pseudoacacia, are very tall and may be competing with the park trees for soil resources and sunlight. Other trees have damage due to mulching and damage from lawnmowers, in particular, Acer saccharums 8 and 9.  There were also a few dead trees and tree trunk stubs in the neighboring blocks.  This was possibly due to the summer 2002 drought, but no definite conclusions can be drawn.

Discussion

The conditions that urban trees face can be harsh, but the importance of urban forests is very large.  The trees on Reservoir Road are doing relatively well for the small amount of soil that they are planted in, the damage inflicted by mowing around them, the pollution around them, and the recent 3-yr drought conditions of 2000 through 2002.

Reservoir Road has very small plots of soil for each tree.  The larger trees, such as Acer saccharum 5 and 12, Robinia pseudoacacia 1, and Ulmus americana 1, are for the most part planted in larger plots of soil where the sidewalk is more narrow.  Also, the larger trees are found in front of the residential houses between 37th and 38th Streets. These houses are mostly occupied by students who do not spend time caring for their gardens and therefore have shady front yards with many small plants and vines. The trees between 38th and 39th are much younger. Also, there are two old tree stumps on the side of the street adjacent to the park, suggesting that certain trees died there. Some were replanted while other stumps have become overgrown with grass and small forbs. The trees evidently compete with the park trees for soil nutrients and sunlight. As a result, the street trees are leaning slightly towards Reservoir Road and away from the trees in the park. The leaf damage on the Acer saccharums is scorch which the drought caused because such damage occurred in many trees in the WDCA.  Interestingly, the trees covered by vines, such as Poison Ivy and English Ivy, looked healthy.  Maybe the vines have not been growing on the trees long enough to cause damage by competing with the trees for resources.  It is also possible that the damage is just obvious to me.  

Conclusion

Healthy urban forests are an invaluable resource for communities.  The trees planted along Reservoir Road are mostly trees that are expected to thrive in urban environments. Robinia pseudoacacias are able to grow on poor soils; the Maclura pomifera is known to be a tough and durable tree. However, the Robinia pseudoacacia are sometimes problematic because they break easily in storms and become weedy. The Maclura pomifera is not as good an urban forest tree because its branches are low, and its fruits may litter sidewalks and other areas. The Acer saccharums and the Acer rubrums are overall better urban trees.  These are more pollution resistant because they tolerate higher concentrations of ozone and SO₂, and can exist in a range of soil conditions. Overall, the trees on Reservoir Road were wisely chosen, and they are thriving in a very demanding environment. If more care is taken to trim the trees from the park, decrease lawnmower damage to the tree trunks, and water the soil to counteract the drought these trees should continue to do well. 

Acknowledgments

I would like to thank Professor E. M. Barrows of the Biology Department of Georgetown University for his time helping in the identification of the trees and in editing this paper. I would also like to express my appreciation to Dan S. Kjar, of Georgetown University, who aided with the technological aspects of this information page. 

Literature Cited

American Forests. http://americanforests.org (2002 11 20)

Barrows, E.M. Biodiversity Book. Georgetown University. 2002.

Maryland Department of Natural Resources Forest Service. Forestry Report R8-FR 17/USDA Forest Service. http://www.dnr.state.md.us/forests/publications/urban1.html (2002 11 20)

Missouri Department Of Conservation. http://www.conservation.state.mo.us/forest/urbantre/index.shtml#table (2002 11 20)

Wilderness WNC Nature Center. http://wildwnc.org/trees/Acer_saccharum.htm (2002 11 20)

Weiss, R. 2002. The Stresses of Summer Force Trees' Survival Out on a Limb. The Washington Post 2 September 2002:11.

 

 

 

 

 

---

Table 1.  Tree types and conditions on Reservoir Road between 37^th and 39^th Streets in Washington, D.C., 2002

---

---

update template
�Copyright 2009 Georgetown University