Urban Heat Island and Trees

Last year we discussed Urban Heat Islands and the effect that they have on the environment and how building owners could help diminish it. One of the ways was to install a cool roof system on a building, like an elastomeric coating system. The other was to increase vegetation around the building.

Source: wikimedia.org

Many cities have put into place a Tree Protection ordinance, prohibiting removing or pruning of trees without a permit. San Antonio, Texas actually requires different levels of free protection based on tree class or location.

There are also Street Tree ordinances that govern how to plant and remove trees along public right-of-ways and land that is privately owned but accessible by the public. For example, Orlando, Florida specifies that trees must be planted along both sides of a street, with one tree every 50 to 100 feet.

Parking lot shade is another way to help reduce the heat island effect and increase vegetation. In Sacramento, California, for example, a code in their zoning code requires that enough trees be planted to shade 50 percent of new parking lots after 15 years of tree growth.

So if you are looking to build or renovate your building, keep environmental concerns in mind and contact your city and see what steps can be taken to minimize the Urban Heat Island.

Urban Heat Islands

Have you ever noticed while driving out of the city into a rural area that the temperature seems to suddenly drop? This is the result of what is called the Urban Heat Island effect, which is a heat bubble that builds up around cities due to buildings, pavement, lack of vegetation and other permeable surfaces.

Scientists have been measuring Heat Islands for years and, as cities grow, so do the Urban Heat Islands. As Heat Islands grow so does energy consumption (more electricity to cool things down) which increases emissions of air pollutants and greenhouse gases from power plants. The increased heat also causes the quality of water to become impaired as hot rooftops and pavement shed their water into the drainage system and out into streams, ponds and other bodies of water, causing rapid fluctuations of temperatures which is stressful to the aquatic ecosystem.

There is a also general discomfort for humans with higher air pollutants and higher temperatures.

The EPA sites four main ways that helps counteract Urban Heat Islands:

• Increasing tree and vegetative cover


• Creating "green" roofs (rooftop gardens or "eco-roofs")


• Installing cool roofs


• Using cool pavements

High performance fluid-applied roofing systems designed and applied by a certified professional roofing contractor are proven to reflect up to 85% of the sun's rays, reducing the temperature by nearly 60 degrees than that of traditional black roofs. Washington Roofing & Insulation uses only the highest quality of material that is ENERGY STAR, LEED, CRRC, Miami-Dade County approved and / or certified.

Source: EPA Website: What is an Urban Heat Island