Big old trees are the urban dweller's best friend
A large scale study in Brussels, Belgium found that preserving existing mature trees in urban areas provides greater benefits in terms of reducing air pollution and improving the quality of life for city residents than planting new trees. Using LIDAR, researchers were able to identify 616,379 trees for the entire region with data on the diameter the crowns, and the density of trunks in a given area. The study then compared the benefits of tree cover to local sales of medicines. Where tree cover was high, medicine sales were low. So trees improved the health of urban residents, but not uniformly. The impact of trees on human health was much greater with old trees with large crowns than with a lot of young trees. The researchers concluded that preserving existing mature trees had a greater impact on carbon sequestration than planting new trees, due to the fact that mature trees sequester more carbon than young trees. The article emphasizes the importance of considering the preservati