New York City’s Trees Work Hard. Still, They Could Use a Little Help.

Oak trees with leaves like outstretched hands and thick, stately trunks reduce the effects of extreme heat around New York City’s five boroughs by shading sidewalks and sucking up planet-warming carbon.These workhorses also naturally emit a chemical called isoprene. Alone, it is harmless. But when isoprene meets nitrogen oxides, a group of gasses emitted when fossil fuels are burned to power buildings and…