The beauty of urban green spaces runs more than skin deep; native grasses growing in street medians, small traffic islands of plants and seasonal blooms planted near parking lots. Many of us don't realize these are countless benefits in this matter, some of them are the following, (1) water quality protection, proper landscaping reduces nitrate leaching from the soil into the water supply and reduces surface water runoff, keeping phosphorus and other pollutants out of our waterways and preventing septic system overload; (2) reduced heat building, trees in a parking lot can reduce on-site heat build-up, decrease runoff and enhance night-time cool downs; (3) reduced soil erosion, a dense cover of plants and mulch holds soil in place, keeping sediment out of lakes streams, storm drains and roads; and reducing flooding, mudslides and dust storms;(4) improved air quality, trees, shrubs and turf remove smoke, dust and other pollutants from the air (Aey, W., 1990).
A recent study trees can remove 26 pounds of carbon dioxide from the atmosphere annually, equalling 11,000 miles of car emissions (Hupfer, P. et al., 1990). One study showed that one-acre of trees has the ability to remove 13 tons of particles and gases annually. Furthermore 2,500 square feet of turf absorbs carbon dioxide from the atmosphere and releases enough oxygen for a family of four to breathe (Aey, W., 1990); (5) lower attic temperatures, trees shading homes can reduce attic temperatures as much ad 40 degrees. According to the Environmental Protection Agency: “Greenscaping, The Easy Way to a Greener, Healthier Yard”(EPA), urban forests reduce urban air temperatures significantly by shading heat sinks such as buildings and concrete and returning humidity to the air through evaporate cooling.
In the other hand there is (6) natural resource conservation, by using trees to modify temperatures, the amount of fossil fuels used for cooling and heating is reduced. Properly places deciduous trees reduce house temperatures in the summer, allowing air conditioning units to rum 2 to 4 percent more efficiently. The trees also allow the sun to warm the house in the winter; (7) green roofs cool urban hot spots, led by cities such as Chicago and Toronto, as well as a number or universities, evidence is mounting that green roofs (i.e. roofs totally or partially covered by vegetation) can play an important role in saving energy, reducing the urban heat island effect and adding more green space to a built environment (Lenton, 2008); (8) cooler summer days, lawns will be 30 degrees cooler than asphalt and 14 degrees cooler than bare soil in the heat summer; (9) natural resource conservation, homeowners can “grass-cycle” by leaving grass clippings on the lawn when mowing. The clippings quickly decompose and release valuable nutrients back into the soil to feed the grass, reducing the need for nitrogen by 25 to 50 percent, and (10) reduced pollution, trees naturally remove pollutants from the air, so every tree that’s subtracted from a city’s ecosystem means some particulate pollution should have been filtered out (Mueller, 2006).
María Santillana
