Article : Best Trees for the Street

Best Trees for the Street

Editor's Note: This article originally included the photo on the left, describing it as "The ‘Natchez’ crapemyrtle (Lagerstroemia)." As many astute readers have noted, the Natchez has white flowers, as shown in the photo on the right. The photo at left shows a crape Myrtle (Lagerstroemia indica)

Scientist John Hammond of the Agricultural Research Service (ARS), the U.S. Department of Agriculture’s chief scientific research agency, has announced the findings of a four-year project to determine the best trees to use in urban spaces.

Hammond, who also heads the ARS Floral and nursery Plants Research Unit in Beltsville, Md., aimed to find “trees that can survive years of service shading city sidewalks or traffic median strips.” Important factors included small to medium size, pest-resistant and low-maintenance trees that do well in environmental extremes. Other benefits included good looks, such as “springtime blossoms, shapely crowns, brilliant fall foliage, etc.” Size was important because if a tree grows too large for the space it occupies, it might have to be severely pruned or even removed entirely to accommodate utility lines or to be safely away from other structures.

Hammond’s team, whose partners included the U.S. Forest Service, the Maryland Department of Natural Resources, the University of Maryland, Washington, D.C.’s Urban Forestry Administration, and local utility companies, found good street tree candidates in the U.S. National Arboretum’s cultivar collection, including three species of red maple (Acer rubrum)—‘Brandywine,’ ‘Somerset’ and “Sun Valley’; red maple (Acer rubrum); ‘Natchez’ crapemyrtle (Lagerstroemia); and the Frontier elm (Ulmus).

The team is also investigating how early cultivation methods affect street tree survival. Initial tests showed that container-started trees outperformed in-ground trees, which do not have to be dug up to be transported and thus undergo less root damage. The team will continue to examine whether any performance related variables hold true as the trees mature.

This “Power Trees Project” ( is important because of the huge amounts of resources required by municipalities to care for trees. One Washington, D.C.-area utility spends about $20 million annually on tree trimming, removal and replacements.

According to USDA’s Economic Research Service data for 2005, woody shrubs, flowers and other ornamentals comprised sales of more than $16 billion.

Older Comments
Name: Alan SiewertWrote in with general comment
Comment: I was disappointed with the article. Tree selection is the one time we have to build a good urban forest. Selecting the right tree for the right site not only for size suitability but also for survival is of utmost importance. Street tree selection must take into account diversity of the population and survivability of the plant in the chosen site. Flower color and fall color are personal choices, different for everyone. City trees are city infrastructure, so who gets to decide what looks nice? Everyone will not be happy. Blacktop can be colored and given pattern but on a city street it is black because that is economically best for the community. We need to get past the idea that street trees are an amenity to make the community look nice and realize they are a necessity for our survival in the community. If residents want red flowers or red blacktop with a nice herringbone pattern in it then they should put them in their yard. Diversity as Len Phillips has commented on, and local expertise picking the trees that are economically best for the site and community are needed. It seemed presumptuous to me that a short four-year study can pick the best street trees. The unfortunate part is homeowners intent on planting the wrong tree in the wrong location will search the Internet and find this article and use it to support their position and the Urban Forester will have to argue against a very good web site.

Name: Arthur BaughWrote in with general comment
Comment: Good article.

Name: James MasonerWrote in with general comment
Comment: I looks like the study was for the eastern United States. It certainly does not apply to the Desert Soutwest.

Name: Kathy ElliotWrote in with correction comment
Comment: The tree pictured (pink-flowered crapemyrtle) is captioned as a 'Natchez' crapemyrtle. 'Natchez' is a white cultivar.

Name: Jim CleesWrote in with correction comment
Comment: Photo at the top of the article is not a 'Natchez' Crape Myrtle. 'Natchez' has white flowers.

Name: Carolyn LewisWrote in with correction comment
Comment: This is not a Natchez - a Natchez is White flowering

Name: Carlos AlanisWrote in with correction comment
Comment: Sorry but the crape Myrtle in this picture is not a Natchez(white) looks to me as a Tuscarora red

Name: Len PhillipsWrote in with general comment
Comment: The article gave the impression that the trees listed were the only trees that met the requirements stipulated. The trees listed are best suited for the Washington DC area and perhaps this should have been stated in the research report. Online Seminars for Municipal Arborists developed a list of 135 urban trees that met the same requires as those stipulated in the article. This list appeared in the Jan/Feb 2007 Seminar and is now available only from the Seminar archives. This list was compiled from municipal arborists and nurserymen all over the northern two thirds of the US. Each Seminar offers a detailed look at one of these excellent urban trees, many of which are actually better than the trees the article reported. Len Phillips Administrator of Online Seminars for Municipal Arborists

Name: Terry FlatleyWrote in with correction comment
Comment: Red maple as a good street tree selection? Your criteria must not have included things like life span, propensity towards included bark, poor resistance to decay, tendency to surface root more than other species, poor high wind resistance and overplanting/overuse.

Name: Tom MyersWrote in with general comment
Comment: I have to agree that red maple is a great tree when in the right location. However, I would limit it\'s use as a street tree especially in our area (northern Indiana). Red maples have a low tolerance for road salt and prefer acid soils. After years of performing root collar excavations I have found that no other tree is as likely to experience severe girdling roots. Add container grown trees to the mix and you\'re looking at a real problem in the future.

Name: Jenn BallardWrote in with general comment
Comment: I was just about to say \'I can\'t believe they chose crepe myrtle and red maple,\' then I remembered that I used to work at BARC and of course they\'d come up with something like this. Red maples are too shallowly rooted for sidewalk street trees. They will pop that sidewalk up - they need to be at least 10 feet from pavement and that\'s an absolute minimum. Also, crepe myrtle is so short that it creates problems with site distance. You want a tree that will not block your view as a pedestrian, cyclist or motorist in a city. Trees for urban areas shouldn\'t just be chosen because the tree can survive - the PEOPLE NEED TO BE ABLE TO SURVIVE THE TREE. People in charge of picking out trees for their cities read an article like this and blindly go along with it.
Two thumbs down.


June 29, 2016, 5:41 pm EST

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