Improved air quality and other services from urban trees and forests

Abstract

Worldwide, there are an estimated 3.0 trillion trees (Crowther et al. 2015) and 7.7 billion people (http://www.worldometers.info/world-population/). These trees produce numerous benefits to society but also create various costs. Trees can improve human health and well-being by moderating climate, reducing building energy use and atmospheric carbon dioxide (CO₂), improving air quality, mitigating rainfall runoff and flooding, providing protection from ultraviolet radiation and soil erosion, lowering noise levels and providing food, lumber, medicines, aes-thetic environments, and recreational opportunities (e.g., Millennium Ecosystem Assessment 2005; Nowak and Dwyer 2007; Costanza et al. 2014). However, trees can also produce environmental and monetary costs associated with allergies from pollen, volatile organic compound emissions, potential increased energy use due to trees near buildings, invasive plants that alter local biodiversity, higher taxes from increased property values, and tree maintenance. Both the positive and negative aspects of trees and forest must be considered when designing landscapes to improve human health and well-being. As trees can be a dominant element in a landscape, understanding the magnitude and the means of how trees affect the environment can lead to better vegetation management and designs to optimize environmental quality and human health for current and future generations. In urban areas, the impacts of trees become more important due to the relatively high concentrations of humans and impervious surfaces that alter the environment.

Citation

Nowak, David J. 2023. Improved air quality and other services from urban trees and forests. In: Bakshi, B.R., ed. Engineering and Ecosystems: seeking synergies toward a nature-positive world. Switzerland: Springer Nature: 215-245. Chapter 10.