What is an Urban Forest?
An urban forest encompasses the trees and shrubs in an urban area, including trees in yards, along streets and utility corridors, in protected areas, and in watersheds. This includes individual trees, street trees, green spaces with trees, and even the associated vegetation and the soil beneath the trees.
Urban forests and trees provide both tangible and less tangible benefits important for a good quality of life. The consumable products include fuelwood, food, fodder, and poles. They improve air, water and land resources, provide habitats for wildlife, control erosion, protect watersheds for urban water supply and can be an outlet for safe disposal of urban wastes. Additional benefits to society, including it low-income citizens are significant and relate to improvement of health, recreation, environmental education, aesthetics, and enhancement of landscape.
Depending on urban forest management objectives, the focus is quite different in wealthier cities and poorer settlements. Multiple purpose urban forests are required for both rich and poor cities.
The majority of the people in the region are poor and have an urgent need for necessities for a reasonable quality of life: adequate food, shelter, potable water and jobs. Urban forests can provide a significant portion of these needs. Urban forests can be set aside for food production, timber for shelter and fodder for livestock. Urban green space also provides recreation and employment opportunities. Diverse basic human needs can be satisfied with products from trees and shrubs; food and fuel are among the most pressing needs in developing countries. Tree products, if sold, provide direct cash benefits; if used within the household they provide indirect cash benefits by freeing cash income for other uses. Trees themselves can improve existing savings/investments, secure tenure or increase property value.
Benefits Of Urban Forestry
Timber and poles
Building materials like poles, branches, leaves for thatching, shade trees for human livestock and crops; windbreaks and shelterbelts for protection of settlements against sand and wind; and living fences to protect and screen living sites are other appreciated values of urban trees. Progress has been made in incorporating timber harvesting and related forest products with intensive outdoor recreation activities in urban forest
Trees are an important source of animal fodder, particularly during dry seasons.
Many urban trees suitable for resource-poor settlements can provide food, particularly fruit, but also edible leaves, shoots and even flowers.
Urban areas tend to be much warmer than the surrounding countryside. Urban vegetation can moderate the heat island effect of urban areas by (i) direct effect on human comfort and (ii) effect on the energy budget of urban buildings, where air conditioning is used. Effects can be either significant or negligible, depending on the size, spacing and design of the urban forests. Trees can modify climate in three ways: by acting as a windbreak, by providing shade and through evapotranspiration. It is reported that tree shade can reduce the average air temperature in buildings
Air quality improvement
While air pollution in many cities in the more developed countries in the region has dropped over the years, air pollution level has been rising in other cities. Planting vegetation to reduce air pollution is increasingly utilized as an effective approach Urban trees interact with the atmosphere and surrounding urban surfaces. It has been suggested that they affect air quality in the following ways. (i) conversion of carbon dioxide to oxygen through photosynthesis;(ii) Trees intercept particulate pollutants (dust, ash, pollen and smoke) and absorb toxic gases such as ozone, Sulphur dioxide, and nitrogen dioxide, thus removing them from the atmosphere. (iii) Trees emit various volatile organic compounds, such as isoprene and monoterpenes, that can contribute to ozone formation in cities. (iv) By transpiring water and shading surfaces, trees lower local air temperatures.
Energy savings, global warming and carbon dioxide reduction
What Trees and related urban vegetation can significantly contribute to improving the air quality by cooling and cleaning the air. Energy conserving landscaping by strategically planting trees can maintain comfort without air conditioning and thus needs to be systematically incorporated in housing projects in resource-poor settlements. Since urban trees reduce the need to burn fossil energy, they are a more important investment for green house mitigation than rural trees.
Noise often reaches unhealthy levels in large cities. Typically, noise from cars, trains and planes. The health risk is high, as shown by research in developed countries. People living close to heavy industry, commercial and traffic corridors often get exposed to the highest levels of noise particularly since all too often the building materials used in low-income settlements do not insulate residents from noise pollution. Trees and other vegetation in conjunction with land forms reduce highway noise.
Water use, reuse and conservation
Trees and other vegetation can help in protection of urban water supply, wastewater treatment systems and storm water management.
Trees can thus be purposefully used to help achieve the objectives of storm water management at optimal costs, which are to prevent the loss of life, to reduce property damage by runoff of severe storms; to prevent land and watercourse erosion, to protect water resources from pollution, to preserve natural watercourses and their ecosystems and to achieve objectives.
With steep terrain and where there is little vegetation and harsh seasonal rains, landslides can be common and can be a constant threat to people's lives and homes. Trees and forests can through water (run-off) management contribute to achieving the best soil erosion control.
Tree planting can also offer a beneficial use for solid waste landfill sites. Recycling of waste from urban forest can play a large role in solid waste management, especially in cities in developing countries, and should be encouraged not only to reduce the need to dispose of vast amounts of waste but also to secure new raw materials from extraction for re-use. Unused and degraded land and landfill sites can be reclaimed through afforestation Irrigated tree plantations can be a safe and productive means of wastewater disposal;
Visits to green areas bring relaxation and sharpen concentration, since people only need to use their spontaneous attention. Certainly, improving air quality through planting vegetation has passive impact on health with such obvious benefits as decreased incidence of respiratory illnesses. Shade trees reduce ultraviolet light exposure, thereby lowering the risks of harmful health effects such as skin cancer and cataracts. For that reason urban forests are increasingly recognized as a component to mitigate ground-level ozone and to reduce air pollution.
Urban forestry can provide jobs for the poor as both skilled and unskilled laborers. Tree planting and especially urban agroforestry systems can be labor-intensive and provide both initial start up jobs as well as more permanent employment in tree care
Urban forests provide many educational opportunities. A number of cities in the region have botanical gardens, zoos, natural trails and even visitor information centers that can inform people about flora and fauna. Education opportunities for urban residents are rare opportunities to learn about nature through first-hand experience.