The heat is on, how to get off the island.

Community SaddleBrooke

What is a community heat island? Higher temperature gradients are most notable in dense urban areas. The loss of vegetation combines with pavement and buildings to increase temperatures. Concrete sidewalks and asphalt absorb heat. According to the EPA, this effect results in average daytime temperatures 1-7 degrees F higher, and nighttime temperatures 2-5 degrees F higher in urban versus natural areas.

Developing communities can experience higher temperatures as vegetation is replaced by buildings. By utilizing best practices, anyone can reap benefits and avoid the deterioration of community home values. The use of “urban” gives a false perspective on community needs. Residents may think there is no concern unless they live in a downtown urban location.

The sheer amount of paved surfaces in any community cause heat retention problems. Buildings, roadways, and sidewalks have replaced natural landscapes.

Momentum is building for strategies to battle community heat. Residents may have concerns about the water for trees. Perceptions can be affected by past practices that allowed inappropriate tree species. Choices for trees have improved over the years. Selection for trees targets species for water efficiency and location.

A community wrestles with trees facts and myths

Reducing heat and providing shade can significantly increase home values. Everyday activities become more enjoyable.
Bureau of Land Management

There are perceptions and myths about trees using too much water. This comes at a shifting time in our nation. A nation has transitioned from “what can you do for your country” to a “me only”. That can make it hard to encourage or require residents to plant trees. Trees and vegetation in the urban environment have benefits beyond mitigating urban heat islands.

EPA Using Trees and Vegetation to Reduce Heat Islands;

  • Reduced energy use: Trees and vegetation directly shade buildings decreasing demand for air conditioning.
  • Improved air quality and lower greenhouse gas emissions: By reducing energy demand, trees and vegetation decrease the production of associated air pollution and greenhouse gas emissions. They also remove air pollutants and store and sequester carbon dioxide.
  • Enhanced stormwater management and water quality: Vegetation reduces runoff and improves water quality by absorbing and filtering rainwater.
  • Reduced pavement maintenance: Tree shade can slow the deterioration of street pavement, decreasing the amount of maintenance needed.
  • Improved quality of life: Trees and vegetation provide aesthetic value, habitat for many species, and can reduce noise.

Costs associated with planting and maintaining trees or other vegetation include purchasing, irrigation, and pruning. A study of urban forestry programs in five U.S. cities showed a range of expenditures: annual costs ranged from almost $15 per tree in the Desert Southwest region to $65 per tree in Berkeley, California.

Phoenix and Tucson are also planting more trees. Many of the trees are targeting neighborhoods most affected by increasing temperatures. Shade structures or trees in parking lots can provide extensive coverage. In Phoenix and other cities, lower-income residents can get trees to plant for free.

Beyond Trees

The Cool Pavements Program is exploring new techniques for paving communities.

EPA Cool Pavements Program
Lawrence Berkeley National Laboratory's Heat Island Group has converted a portion of a parking lot into a cool pavement exhibit.Lawrence Berkeley Laboratory

Conventional materials can be replaced by reflective surfaces that remain cooler. Newer surface materials improve stormwater management.

Phoenix is a participant in the cool pavement program. The city has miles of streets that have been treated with a reflective coating. Arizona State University is studying these new paving techniques. They have found that the coating could lower the surface temperature by as much as 12 degrees. It also decreases the air temperatures at night.

Additional steps are used in the battle against heat. Other cities beyond the southwest are seeing higher temperatures. Some cities are experiencing temperatures normally reserved for Phoenix. Phoenix is employing a variety of programs in their battle against climate change.

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Saddlebrooke, AZ

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