Between 2000 and 2010, the U.S. Department of Agriculture (USDA) Forest Service reports that urban land use in the United States increased from 2.6 percent of the overall land surface to 3 percent. That might not sound like much, but that works out to an increase of 10 million acres, from 58 million acres to 68 million acres. Moreover, urban sprawl is just getting started—according to a new Forest Service study, urban land surface in the lower 48 states is expected to more than double between 2010 and 2060, hitting a total of 163 million acres and 8.6 percent of the total overall land area. That’s a lot of new city blocks, but the Forest Service report also argues that urban forest space will necessarily be an integral part of that expansion.
Published in the Journal of Forestry, the paper—entitled “US Urban Forest Statistics, Values, and Projections”—reveals that that projected increase in urban land use amounts to an area larger than the entire state of Montana. As urban land usage increases—and with it, the number of households crammed into that space—the paper argues, so too will the toll cities take on both their residents and the environment.
But urban forest space, the paper argues, can help. According to the study, U.S. urban forests currently encompass roughly 5.5 billion trees and contribute more than $18 billion in societal benefits to the areas that contain them. “A healthy and well-managed urban forest can help reduce some of the environmental issues associated with urbanization such as increased air temperatures and energy use, reduced air and water quality, and increased human stress, and ultimately help people living within and around urban areas,” said David Nowak of the USDA Forest Service‘s Forest Inventory and Analysis Program, the lead author on the paper.
Some of the states expected to have the largest increases in urban land usage by 2060 include California, Texas, Florida, North Carolina, and Pennsylvania. States currently featuring the largest percentages of urban land usage include New Jersey, Rhode Island, Massachusetts, Connecticut, and Delaware. All of these states, the paper argues, would be well advised to think strategically when it comes to using urban forest space to help mitigate the impact of their urban growth over the next 50 years.
Of course, forested areas can bring with them their own dangers as well, especially as the effects of climate change become more pronounced. The California wildfires in 2017 caused more than $5 billion in housing damages. However, urban forests can help combat the very phenomena that are contributing to the worsening of those and other natural disasters. Trees and other plants absorb carbon dioxide from the atmosphere and in turn give off oxygen, serving as natural filters of the greenhouse gas.
According to the 1998 research paper “Sustaining America's urban trees and forests: a Forests on the Edge report,” originally published in the Journal of Arboriculture, urban forests in the United States store approximately 800 million tons of carbon. It was then estimated that, if the U.S. were to increase its urban tree cover by 5 percent in the next 50 years, urban forests could increase those carbon stores by 150 million more tons.
“By measuring and monitoring urban forests, society can better understand the value urban forests deliver, and how urban forests and their role in reducing pollution and reducing energy costs changes over time,” said Tony Ferguson, Director of the USDA Forest Service’s Northern Research Station and the Forest Products Laboratory.