The real providers of heat relief are shade trees – simply put they cool things down. Outdoors benefits from lower temperatures by a process called evapotranspiration where the tree leaves turns liquid water to water vapor which cools the air. Trees clean the air of pollutants, catch dust, take in CO2 and provide oxygen. A well placed tree has indoor benefits also, since their foliage blocks the sun from streets, drive ways, large windows, and prevents the home from absorbing the heat. AC units do a lot less work in cooling homes if a large tree shades the roof. A single tree equals the work of 5 air conditioners. Trees cut down on energy usage and saves on bills in an environmentally friendly way. When the weather starts to turn cold, the leaves drop, allowing heat and sunlight through when you need it. These same trees may provide a windbreak in winter reducing heating costs from 20-50 percent.
THE ADDED VALUE OF SHADE TREES TO A COMMUNITY
Children and adults are much more likely to do activities outside such as jogging or playing when trees provide shady solace from the heat. Just a brief visit to any neighborhood filled with trees shows us the impact trees have on our sense of well-being. When neighborhoods are full of trees residents spend more time outside mingling with neighbors and building personal ties, stronger communities, and a greater sense of well being. In laboratory research, visual exposure to settings with trees has produced significant recovery from stress within five minutes, as indicated by changes in blood pressure and muscle tension. Dr. Roger S. Ulrich Texas A&M University People show fewer acts of aggression – including drivers, there are fewer cases of domestic abuse on streets lined with trees, people concentrate better, kids indicate that they have better self-discipline and the effects of AD/HD are lessened when trees are in sight. So plant trees for our children (and grandchildren). Isn’t that cool!
referenced from Tree Utah & The Department of Environmental Protection