Publications

Michael R. Freiburger, Colleen Murphy-Dunning, Danica A. Doroski, P. Mark Ashton, Jacob D.J. Peters

The 10/20/30 rule is a common rule of thumb for planting trees in urban areas, but its connection to ecological theory and traditional biodiversity is unclear. The rule states that no more than 10%, 20%, or 30% of trees in a city should belong to the same species, genus, or family, respectively. We compared two accepted biological diversity metrics (Shannon diversity and taxonomic distance) with the logic of the 10/20/30 rule. We utilized tree planting data for New Haven, Connecticut, USA and evaluated these data at three municipal scales: city, neighborhood, and census block as well as 86 grids of increasing cell sizes (from 10 × 10 m to 11.5 × 11.5 km). To determine whether the 10/20/30 rule aligns with diversity metrics, we created a function that follows the logic of the rule and quantifies the relative pass or failure of a site. Our “rule index” was significantly correlated with the two diversity metrics irrespective of spatial scale, leading us to conclude that it is a useful guide for planting. We suggest that consideration of the 10/20/30 rule at smaller spatial scales such as census blocks in larger cities could yield benefits for both biodiversity and social equity.

ABSTRACT: It is well-documented that people of color in the U.S. are disproportionately exposed to extreme urban heat. However, most studies have focused on large cities for one point in time, and less is known about how heat exposure changes over time in smaller cities. Here, we present a study of the changing nature of urban heat exposure and cooling strategies for ten cities in Connecticut in the U.S. Our results show that people of color experience more heat exposure and fewer adaptation strategies. They experienced higher overall temperatures, more extremely hot days, and larger increases in heat exposure. Also, they have lower air conditioning ownership rates and lower tree cover. Taken together, the results indicate that people of color are not only exposed to higher temperatures but also disproportionately exposed to increasing temperatures over time. With lower heat adaptation capacity, people of color are more vulnerable to increasing urban heat.

Dexter H. Locke; Matthew Baker; Michael Alonzo; Yichen Yang; Carly D. Ziter; Colleen Murphy-Dunning; Jarlath P.M. O’Neil-Dunne

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