Environment

Carbon Offsets for Urban Trees Are on the Horizon

Austin, Texas, and King County, Washington, are testing carbon credits for planting and protecting urban trees.
Pedestrians pass trees with brilliant fall leaves at Seattle's Green Lake Park.Elaine Thompson/AP

The evidence is in: Urban trees improve air and water quality, reduce energy costs, and improve human health, even as they offer the benefit of storing carbon. And in cities across the country, they are disappearing.

A recent paper by two U.S. Forest Service scientists reported that metropolitan areas in the U.S. are losing about 36 million trees each year. The paper, by David Nowak and Eric Greenfield, was an expansion of the same researchers’ 2012 study that found significant tree loss in 17 out of the 20 U.S. cities studied.