From Scott Carlberg

During the recent heat wave, did you notice something, like I did? When I went to the store, I looked for the parking spot that might have a bit of shade from a tree in the median. Those spots were usually taken. People waiting for rides found shade from an awning or tree. People walking their dogs had a long leash so they could stand under a tree while their dogs wandered.

Finding shade is tougher now. We are losing 36 million trees a year in the US, says the Forest Service. That’s especially unhappy news when there is a heat wave. Trees can help lower temperatures by 10 degrees. (Source)

Cities feel the heat the most. The effect is an urban heat island. The hard surfaces of a city can take-in the heat and make those areas hotter. They absorb heat in the day and release it at night. Trees shade those heat absorbing surfaces or take their place, and leaves transpire water and create a cooler feel.

Tree cover change by state from US Forest Service. Darker shaded states = bigger losses. Hash marks mean the loss is statistically significant.

The short answer: Plant trees. “Trees in urban areas … annually reduce electricity use by 38.8 million megawatt hours for a savings of $4.7 billion, heating use by 246 million British thermal units, saving $3.1 billion, and avoid thousands of tons of emissions of several pollutants valued at $3.9 billion per year. Average reduction in national residential energy use due to trees is 7.2 percent.” (Source)

While planting one tree can help shade a small area, it is better when neighborhoods or cities coordinate. It “creates a profound cooling effect” says a researcher at the University of Wisconsin. From the research: “To get the maximum benefit of this cooling service, the study found that tree canopy cover must exceed 40 percent. In other words, an aerial picture of a single city block would need to be nearly half-way covered by a leafy green network of branches and leaves.”

Trees provide more than heat relief. Here are a few benefits (source):

  • Less air pollution – Trees absorb carbon and remove pollutants from the atmosphere.
  • Energy emissions reduction – By reducing energy people save pollution created at power plants.
  • Better water quality – Trees are like water filters for dirty surface water.
  • Flooding reduction – Trees absorb water and reduce runoff.
  • Protection from UV radiation – Trees absorb 96% of ultraviolet radiation.

Trees can provide shade and save energy

Call to action?

Yes, we have a call to action. Learn about trees and then go to your homeowners association, neighborhood group or city council. Are there ways to protect old trees? Can places be planted with a stand of new trees? Consider what you can do in your yard to shade your home. Help your city plant trees through local nonprofit groups.

Finally, here’s something from SC Living, the electric coops magazine. The writer is S. Cory Tanner, from Clemson College of Agriculture, Forestry and Life Sciences. “Returning to Clemson University to pursue a doctorate exactly 20 years after I first stepped onto campus as an undergraduate, I’m reminded of a favorite saying: ‘The best time to plant a tree is 20 years ago; the second-best time is now.’ Today, I meander through mature, shade-bearing oaks I remember as small trees, because someone planted them during my first tenure.”

Who is managing trees well? The City of Baltimore. From the Christian Science Monitor: How Baltimore is saving urban forests – and its city  With concern growing about climate change and rapid worldwide urbanization, city forests have emerged as one widely touted solution to a host of social and environmental challenges.

When is the best time to plant trees and shrubs? Here’s information from the NC State Extension Service.

Reforestation, from the NC State Extension Service.

Tree Planting Guide from the SC Dept of Forestry.

South Carolina Urban Tree Species Guide.

Finally, safety. Think about power lines when you plant. notes: “Trees that grow too close to electric lines can create shock and fire hazards as well as power outages. More importantly, children can become victims of electric shock when they climb trees that have grown too close to the power lines as well. Trees growing into power lines can also create electrical hazards for people who might be trimming branches, hanging lights or otherwise working around them.” See the website for more.

811: Check this site – Call811 – to learn about digging. Not all utilities are above ground.