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The cooling effects of large urban greenspaces is well established; now scientists from Forest Research, the research agency of the Forestry Commission, have studied small and medium sized parks in London to determine the optimum size, distribution and composition of urban greenspaces needed to achieve urban cooling. The work, published online in the journal Urban Forestry and Urban Greening, analyses data from eight London greenspaces with areas ranging from 0.2 to 12.1 ha. Very small greenspaces with areas of less than 0.5 ha (slightly smaller than an average football pitch) did not affect the air temperatures of their surrounding areas; however as the area of greenspace increased the distance over which cooling was achieved increased linearly. Spaces with more tree canopy coverage increased the distance beyond the boundaries of the greenspace over which cooling was measureable, while the amount of cooling was more strongly linked to the amount of grass coverage present. The researchers found that on calm warm nights they estimate that a network of greenspaces of around 3-5 hectares each situated 100-150 m apart would provide comprehensive cooling for a city with a climate and characteristics similar to London. More