Do we have enough space for the trees we need?

Abstract

In 2021, two guidelines were introduced with the purpose of increasing cities’ tree canopy coverage (TCC): Konijnendijk’s 3–30–300 rule, where 30 represents the goal to achieve at least 30 % TCC, and the Swedish Environmental Protection Agency’s (SEPA) guideline, aiming for all Swedish cities to increase their TCC by two percentage points (%pts) within a period of 10 years. While these ambitious goals are positive, not least from a sustainability perspective, there is a lack of research on whether these goals are feasible and how to reach them in practice. The overall TCC in Uppsala, Sweden’s fourth largest city, is 28 %, with considerably lower TCC in the eastern parts of the city. In this study, we will investigate, and visualise, how a 2 %pts increase as well as 30 % TCC could be achieved in two areas in eastern Uppsala: Fålhagen, a residential area, and Boländerna, a commercial and industrial area. We used geographical information systems (GIS) and a scenario approach to calculate the number of trees needed, and possible locations for them, to achieve a 2 %pts increase or the 30 % TCC goal. The results show that an increase of 2 %pts seems possible in both areas, particularly if the municipality and private property owners collaborate. However, it is difficult to estimate the time needed until the canopies of the proposed trees have become large enough to reach the 2 %pts increase. It does not seem likely to reach 30 % TCC in eastern Uppsala with today’s land use. To be able to reach the goals presented in this paper, it seems necessary to include them in municipality policies. Perhaps Konijnendijk’s and SEPA’s guidelines can be starting points for such policies and applied as rules-of-thumb rather than applicable planning tools.