A6.9 Direct cooling
Combine direct cooling value (urban heat island mitigation) with carbon sequestration value when evaluating urban tree management.
When there’s unusually hot weather in Western Washington, the urban heat island effect is cities like Seattle is significant. Over time, climate change is expected to increase the number of really hot days, so this may become a more important issue.
The large difference between urban temperatures in Portland and those in rural areas around it gave it the fourth highest urban heat island rating out of the 60 US cities Climate Central evaluated. Portland is an average of 4.8 degrees warmer than the rural areas, but on very hot days the difference can be up to 19 degrees. (A recent MIT study concluded that cities laid out on a grid, like Portland, accumulate more heat than those with irregular street patterns.)