Urban trees reduce flooding, heating, cooling costs
By Sara Scudier
OSU Ext. master gardener volunteer
An amazing 80 percent of Americans now live in cities. Having green areas and trees in urban areas is an important aspect of daily life, adding many benefits for all of us.
Urban environments result in more water running off impervious surfaces such as roofs, driveways, streets and parking lots. This run-off increases flooding and pollution of waterways. The concentration of people reduces air quality because of the large number of vehicles and industrial activity. Concentrations of people also intensifies conflict among the cities’ residents. It may seem too simple, but studies have shown that planting trees can help reduce many urban problems.
On of the most basic improvements is improved visual appeal. It’s hard to understate the value of trees with seasonal interest. For example, crabapple blooms in spring. Trees also help reduce carbon dioxide in the air by storing it in their trunks, bark and leaves. They reduce particulates in the air as well. Trees help slow water runoff and thus reduce flooding and water pollution. Buildings in cities increase wind speed, which trees can help slow. The shade from trees reduces air temperature and reduces heating costs in summer.
One of the most amazing things that trees can reduce is crime. Studies have shown that both violent and petty crime rates drop when there is a healthy tree canopy. This healthy canopy also increases property values. Trees provide habitat for wildlife such as birds and squirrels.
While trees are a valuable addition to the urban environment, this environment does not make it easy for them to survive. Urban soils are compacted, with little or no organic content. This means that the food and air trees need to survive and thrive are almost nonexistent. Water during the initial planting phase needs to be regular and thorough.
Many of these concerns can be overcome when trees are planted on private property. The homeowner who chooses to plant is engaged enough to care for the young trees. Public trees are more difficult. It is rare that a city can afford to hire staff to regularly care for newly planted trees. These sites may have problems as well. Tree roots need space to grow and many tree lawns (devil strips to those of us from Northeast Ohio) are often narrow. With good planning, proper planting and active maintenance, urban trees can thrive.
Plan to attend our free Urban Tree Program, part of our Naturalist Series, July 11 at Mill Creek MetroParks Fellows Riverside Gardens. Jim Chatfield will lead us through a program on understanding, selecting and caring for urban trees. You can learn more about the program at http://go.osu.edu/urbantrees.
For a color bulletin on selecting urban trees for your site, visit http://go.osu.edu/selectingtrees.