Title: Oxygen production by urban trees in the United States

Author: Nowak, David J.; Hoehn, Robert; Crane, Daniel E.

Year: 2007

Publication: Arboriculture & Urban Forestry. 33(3): 220-226.

Abstract: Urban forests in the coterminous United States are estimated to produce ≈61 million metric tons (67 million tons) of oxygen annually, enough oxygen to offset the annual oxygen consumption of approximately two-thirds of the U.S. opulation. Although oxygen production is often cited as a significant benefit of trees, this benefit is relatively insignificant and of negligible value as a result of the large oxygen content of the atmosphere. Other benefits of the urban forest are more critical to environmental quality and human health than oxygen production by urban trees.