Trees can play numerous roles in the city: in addition to providing a pleasant environment, they improve air quality, reduce soil erosion, reduce the danger of floods and contribute to improving the social environment.
“Urban forests” absorb carbon dioxide and convert it into oxygen, helping to reduce the CO2 emissions that contribute to global warming. In addition, they filter out environmental pollutants such as nitrogen dioxide or sulfur dioxide and cause dust to be suspended in the air. According to a study carried out in car parks by McPherson and Simpson (2000), the low temperatures associated with the shade of trees can reduce the percentage of hydrocarbons that evaporate from the fuel of automobiles. In this sense, its value is incalculable since the control of air pollution in cities by other means is very difficult.
Although ozone plays a very important role in the stratosphere by absorbing ultra-violet rays, it is toxic to humans, causing respiratory problems whose main symptoms are coughing and chest pain. Trees, by providing shade, can significantly reduce ozone levels in cities, bringing benefits to public health.
The root system and the canopy of trees stabilize the soil, limit runoff, conserve groundwater and reduce the risk of floods that, in recent years, have affected numerous metropolitan areas in our country. Plants also mitigate variations in temperature at microclimate level, making the surrounding buildings not lose so much heat in winter and not so much in summer, which can reduce energy costs.
On the other hand, these areas can have varied social functions. In addition to encouraging healthier outdoor activities, such as sports, games or outings, they can be authentic living laboratories that guarantee the presence of wildlife, where you can learn about nature and observe the rhythms of the seasons. It should also be noted that the dense hedges and bushes attenuate the noise that, in a modern city, can easily exceed the acceptable intensities.
Finally, these “urban forests” can be economically viable. The English project entitled “The Black Country Urban Forest” made these structures profitable by exploring their wood, coal or even fruits and nuts. Another advantage would be the need to create more jobs to exploit these areas commercially.
Trees are more than a beautiful prop in a setting, they produce a functional infrastructure that contributes significantly to the quality of life in urban centers, both at an environmental level and at a social and economic level. Unfortunately, we continue to see the destruction of the scarce green areas in our cities for the construction of buildings or car parks.