Research measures cooling power of trees and parks

Scientists from Forest Research, the research agency of the Forestry Commission have calculated the density of parks and trees required to counter the urban heat island effect.
The study of eight small and medium-sized London parks sought to determine the optimum size, distribution and composition of urban green spaces needed to achieve urban cooling.
It found that very small green spaces with areas of less than 0.5ha did not affect the air temperatures of their surrounding areas, but that as the area of green space increased, the distance over which cooling was achieved increased linearly.
Green spaces with more tree canopy coverage increased the distance over which cooling was measurable, while the degree of cooling was more strongly linked to the amount of grass coverage present.
On calm warm nights, they estimate that a network of green spaces of around 3-5 hectares each situated 100-150m apart would provide comprehensive cooling for a city like London or build up areas across the West Midlands.
Dr Kieron Doick who led the research said: “Trees and areas of grass both have an important role to play in aiding the cooling of cities.
“This could help urban planners to design environments that can lead to lower temperatures in cities.”
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Posted on 29th April 2016