On a hot day I often walk through John D. Morgan Park in Campbell because it is cooler than the surrounding areas. But I didn't know until a few years ago why the park was cooler, even in direct sunlight, until I visited the Sacramento Tree Foundation.
I discovered that trees not only shade us from the sun, they also reduce ambient temperature. Trees transpire water which cools the air by taking heat from the air to evaporate the water. What's more, trees filter pollution, such as C02; reflect solar radiation, reduce energy consumption, provide habitats for birds and other animals, and add beauty to the landscape. Heat Island Effect According to the Environmental Protection Agency (EPA), each year heat is responsible for most of the weather- related deaths of thousands of Americans. What makes matters worse is a phenomenon called the "heat island effect. " EPA describes the heat island effect as "urban and suburban temperatures that are 2 to 10 degrees Fahrenheit hotter than nearby rural areas." The main reason urban areas are hotter is due to the replacement of trees and other vegetation with heat absorbing infrastructures, such as buildings and roads. In areas like downtown Sacramento, which has fewer trees than the surrounding communities, the ambient temperature is higher. Structures, such as dark colored rooftops, concrete, and asphalt also contribute to the "heat island effect." Dark-colored surfaces have a low albedo whereas trees and light- colored surfaces have a high albedo. Albedo stands for the surface's ability to reflect rather than absorb solar radiation. Rooftops, asphalt and concrete absorb solar energy, raising surface temperature 50-70 degrees Fahrenheit hotter than the ambient temperature. These structures reflect, store and release heat into the air even after dark. San Jose's efforts to mitigate the heat island effect In 2001 the City of San Jose adopted a Green Building Policy that includes as one of its objectives suitable landscape design to mitigate the heat island effect. Our City Forest, a non-profit organization, in partnership with the City of San Jose, has planted 50,000 trees over the last 15 years. Last month, for instance, Our City Forest helped San Jose residents, and students and school employees from Laneview and Cherrywood elementary schools to plant 54 trees. Our City Forest gives free 15-gallon shade trees to individuals, parks and neighborhoods. The organization also gives free presentations. If you want to plant a street tree in San Jose, contact the City of San Jose Arborist's Office at (408) 277-2762 or Our City Forest 408-998-7337.
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AuthorWilly TA Mills is just another regular guy. I just wanted to talk about different things going on. What I like and have fun with it. Archives
November 2017
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