Tree Canopy Cover and the Development of Asthma – What’s the Connection?

Researchers, reporting in the January edition of Environmental Health Perspectives, note that “urban landscape elements and trees in particular have the potential to affect airflow, air quality, and production of aeroallergens. Several large-scale urban tree planting projects have sought to promote respiratory health, yet evidence linking tree cover to human health is limited. [The authors] sought to investigate the association of tree canopy cover with subsequent development of childhood asthma, wheeze, rhinitis, and allergic sensitization. Birth cohort study data were linked to detailed geographic information systems data characterizing…tree canopy coverage….[The] results did not support the hypothesized protective association of urban tree canopy coverage with asthma or allergy-related outcomes. Tree canopy cover… was associated with higher prevalence of allergic sensitization to tree pollen. Information was not available on sensitization to specific tree species or individual pollen exposures, and results may not be generalizable to other populations or geographic areas.”