A patch or strips of trees planted in the urban or semiurban areas to protect the environment from its degradation and to decorate the urban landscape for their scenery. Urban Forestry aims at raising and management of trees and green areas in urban and semi-urban centre. Urban forestry includes management of municipal lands, management of watersheds in urban areas, wildlife habitats, opportunities for outdoor recreation, landscape design, recycling of municipal wastes, tree care, etc. Urban forestry includes green belts, parks and gardens, zoological parks, forest reserves, avenues

Effects of urban forests on environment

1. Air quality improved: absorption of air pollutants by leaves or soil surface.

• Deposition of particulates and aerosols on surface of leaves
• Sulphur di-oxide of air absorbed by trees

2. Moderation of temperature: Helps in controlling extremes of temperature

• Provide shade that reduces solar radiation
• Plants absorb heat as they transpire

3. Noise reduction: Noise levels reduced due to trees

4. Micro-climate amelioration: Micro-climate is ameliorated so that extremes are lowered

5. Fauna: Trees and other forms of vegetation harbor various faunal species which add to the quality of life in urban areas

6. Erosion control

7. Landscape aesthetics: Landscape aesthetics of plants are becoming more highly valued

8. Water quality improvement

9. Carbon sequestration

Plant environmental (abiotic) stress constitutes a major limitation to urban forestry. The major plant stresses are: drought, cold, heat, salinity, soil mineral deficiency, soil mineral toxicity. Besides these, acid rain, gaseous and particulate pollution, security lighting, and toxic wastes also cause stress

Stress encountered by plants

• Compacted soil
• Insufficient nutrition
• Air pollution
• Little or excessive water supply
• Infestation by pests and pathogens
• Extension of day length by night lighting
• Light intensity variation from deep shade to full sun
• Reflection increases air temperature in urban areas
• Accidents, vandalism, neglect
• Hails, frost

Stress can be avoided/minimized by choosing a favorable site, preparing site for planting, selecting plant that are tolerant to site and relatively pest resistant and caring for plants to ensure vigorous growth

Urban plant species

Eucalyptus species, Azadirachta indica, Jacaranda mimosifolia, Melia azedirach, Albizzia procera, Grevelia robusta, Polyalthia longifolia, Prunus cerasoides