Quantifying the Role of Urban Forests in Removing Atmospheric Carbon Dioxide    (View PDF)

Rowan A. Rowntree and David J. Nowak

Abstract: Urban land in the United States currently occupies about 69 million acres with an estimated average crown cover of 28% and an estimated tree biomass of about 27 tons/ acre. This structure suggests that the current total urban forest carbon storage in the United States is approximately 800 million tons with an estimated annual net carbon storage of around 6.5 million tons. Besides directly storing carbon, urban trees also reduce carbon dioxide (CO2) emissions by cooling ambient air and allowing residents to minimize annual heating and cooling. Approaches for understanding urban trees and CO2 flux are described at four scales: the nation, the city, the organization, and the individual. A method is provided that allows one to easily estimate the amount of carbon stored in an urban forest and sequestered annually by that forest. A method is provided for organizations to calculate the number of trees necessary to offset the CO2 emissions associated with the energy used in their office buildings. Tables are also provided to show how many trees an American could steward or plant to offset his or her per capita carbon emissions (2.3 tons/year).

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https://doi.org/10.48044/jauf.1991.061