Urban trees and the risk of poor birth outcomes

Previous studies suggest a possible link between urban greenness and health and thus birth outcomes. Here, the authors studied the effects of trees on birth weights for babies born into families living in single-family houses. Gestational age, birth weight, mother’s address, and some demographic information were determined from birth certificates. A number of markers of socioeconomic status were controlled for. Addresses were geocoded, and percent tree canopy cover within 50, 100, and 200 m was determined from aerial imagery. There was a reduced risk of low birth weight (below 10th percentile) with higher levels of tree canopy cover with 50 m of a house, though the results were relatively modest.