Demonstration to show cooling power of trees



With summer heat expected to envelop the Vancouver area this weekend, the Master Gardeners of WSU Extension Clark County will visit Esther Short Park on Saturday afternoon to demonstrate both the “heat island effect” that occurs in urban areas, as well as the natural, air conditioning benefit that trees offer.

Starting at 2 p.m. on the north side of the park, the group will use a laser thermometer to take temperature readings in the shade and in exposed sunlight — to point out the “astounding” difference, according to event organizer Erika Johnson.

The heat island effect was first observed in the 1800s as scientists observed cities growing far hotter than rural areas in summertime. That’s because artificial, impervious structures absorb more solar energy.

Trees, meanwhile, provide shade and “evapotranspiration,” which leads to cooler conditions.

According to the Environmental Protection Agency, evapotranspiration alone or combined with shading can reduce peak temperatures by as much as 9 degrees Fahrenheit.

Vancouver Urban Forestry and Friends of Trees will also be on hand to provide resources on planting and protecting urban trees.

Strategically planting trees and other vegetation can mean cooler buildings and lower air-conditioning costs; trees in urban areas also offer cleaner air, stormwater mitigation and higher property values.

To find out if Friends of Trees is planting in your neighborhood soon, call 503-282-8846 or visit The Portland nonprofit agency makes street trees available for $25 and yard trees for $50.

For more information on the WSU Extension Clark County Master Gardeners, contact Erika Johnson at or 360-397-6060, ext. 5738.