Small and medium sized parks and urban green spaces provide similar benefits to cities as larger areas, helping to cool the surrounding temperature and mitigate the urban heat island effect, says new research from the U.K.’s Forestry Commission. The study evaluated the effect of eight urban green spaces in London with areas varying from 0.2-12.1 hectacres (about 0.5-30 acres) and found that while spaces under 0.5 ha (1.2 acres) did not affect the surrounding areas, as the space’s size increased past 0.5 ha, so did the cooling effect.
The researchers found that just 3-5 spaces with sizes ranging from 3-5 ha (about 7.5-12 acres) spaced around 100 meters apart from each other could provide significant cooling effects to a city similar to London, though climate and specific urban characteristics will factor into performance. The data, published in Urban Forestry and Urban Greening, also demonstrates that while more tree coverage in a green space helps to move the cooling effect further geographically, grass helps amplify the cooling. Researchers recommend that planned spaces include a mix of the two elements to maximize cooling benefits.