Study Supports PlaNYC Plans to Plant 1M Trees by 2017

Part of Greensburg, Kansas’s rebuilding plans include the encircling of the town with rows of protective trees, meant to shield the town from high winds and minimize the impact of future tornadoes.

An article in this month’s Journal of Epidemiology and Community Health explores how the prevalence of trees may benefit young children in urban areas for totally different reasons. MedPage Today reports:

Young children who live in city neighborhoods with tree-lined streets are less likely to develop asthma, but the actual protective factor remains unknown, researchers said.

Asthma rates in preschoolers would fall by 24% to 29% for every standard deviation increase in tree density, equivalent to an additional 343 trees/km

The study, which was funded by the National Institute for Environmental Health Science and the Robert Wood Johnson Foundation’s Health & Society Scholars Program did recognize that,

“Trees may help prevent asthma, either by encouraging outdoor play or through an effect on local air quality,” the researchers said. “On the other hand, trees are a source of pollen and may exacerbate asthma among children with atopic asthma.”

It’s also possible that other factors could be responsible for the protective effect, said Dr. Lovasi.

“For example, trees could be more abundant in areas that are well maintained in other ways,” she said, “leading to lower exposure to allergens like mold or cockroaches that we know are important triggers for asthma attacks.”

Even with the confounders, the study concludes that street trees were associated with a lower prevalence of early childhood asthma and looks forward to the PlaNYC sustainability initiative to offer an opportunity for a larger evaluation. PlaNYC plans to plant one million trees by the year 2017, as well as reduce emissions by 30% by 2030.