A systematic quantitative review of urban tree benefits, costs, and assessment methods across cities in different climatic zones

This article provides a comprehensive overview of the research on urban tree benefits. The authors considered the research methods, locations where research was conducted, results, and important research gaps. A systematic quantitative literature review of English-language journals in scholarly electronic databases was conducted as the foundation with “urban trees” and related topics as the main keywords. A total of 115 peer-reviewed articles were found, published in 33 journals covering a wide range of disciplines. Research was predominantly North American (63.5% of papers), but all continents (except Antarctica, of course) were represented. With regard to research methods, the majority of papers employed natural sciences methods (60%); social sciences and mixed methods each represented only 14% of the research. Nearly all studies made use of quantitative research strategies. Thirty percent of the papers addressed urban tree benefits, a little more than half considered ecosystem services provided by urban trees, and 16% discussed disservices. The Discussion section includes some comparisons of results from studies in different regions and concludes with recommendations for future research. In particular, the authors note the need for research outside the United States.