• Today, the most important aspect of the urban forest is clearly energy conservation and carbon dioxide absorption.
• Studies show that hospital patients with window view of trees recovered significantly faster and with fewer complications than comparable patients without access to such views.
• Windbreak of trees have been found to reduce residential heating costs 10-15%
• Trees intercept rainfall and reduce run-off, thereby functioning like retention/detention basins.
• The psychological impact of trees on people’s moods, emotions and enjoyment of their surroundings may in fact be one of the greatest benefits urban forests provide.
• Properly located and managed, trees can reduce the demand for fossil energy through effects such as shading buildings to reduce air conditioning demand, breaking winter winds to lower space heating needs, preventing soil erosion to lower the amount of fertilizer needs and fossil fuel that would be needed to produce necessary foods and fibre from higher acreages of degraded soils, manipulating snow drifts to reduce winter snow ploughing costs and automobile accidents, and sheltering livestock in both winter and summer to reduce stress and improve feed efficiency.
• Trees and shrubs are effective insulation against noise.

Urban Trees Reduce CO₂

• by directly removing carbon;
• by reducing energy needs (for cooling and heating by planting around buildings)

Environmental Impact

• Each healthy tree can reduce air borne dust particles by as much as 7,000 particles per litre of air, thus a healthy tree is a free standing air conditioner and purifier
• You need about 500 full-sized trees to absorb the carbon dioxide produced by a typical car driven 20,000 km/year

Consumption

• Fossil fuel consumption puts CO₂ into the atmosphere from reserves held within the earth. CO₂ production from hearting the average Canadian home:
  by oil - 7 tons/year;
  by natural gas - 5 tons/year;
  by electricity - 1.3 tons/year;
  by wood - 0* tons/year.
  
  Source: Voluntary Challenge and Registry Program Participant's Handbook, August 1995 and addendum March 1996, Environment Canada
  
  
• CO₂ from running -
  economy car - 20,000 km (gas) = 6 tons
  heavy truck - 20,000 km (diesel) = 26 tons
  
  
• Trees can help reduce the greenhouse effect in two ways:
  1. trees directly absorb CO₂ - the primary greenhouse gas - from the atmosphere during photosynthesis;
     
  2. shade from trees can reduce air conditioning and energy use, which reduces the amount of CO₂ emitted by power plants.
     
     
• On a carbon saving basis alone, urban trees provide greater benefits that rural trees, because they reduce carbon emission by reducing costing / heating energy consumption.