Researchers from Columbia University found lower rates of disease among children who lived in areas of the city with more trees.
Asthma rates among children aged four and five fell by 25 percent for every extra 343 trees per square mile, the study found.
Dr. Gina Lovasi from Columbia University told Scotsman news, "Street trees may explain geographic variation in the prevalence of asthma within urban environments. Trees may help prevent asthma, either by encouraging outdoor play or through an effect on local air quality."
Latest data analysis shows that U.S. rates of childhood asthma soared 50 percent between 1980 and 2000, with particularly high rates in poor, urban communities.
In New York City, asthma is the leading cause of admission to hospital among children under 15, according to the BBC.
The study appears in the Journal of Epidemiology and Community Health.
