COS 226-3 - Historical urban development affects current forest distribution, composition, and structure and is related to inequitable distribution of forests and biodiversity

Abstract: The distribution of infrastructure, industry, socio-demographic groups, and green spaces in urban systems is related to the ecological and—the often racially biased—developmental history of cities. This has resulted in patterns of inequity, with minoritized communities often having less access to green spaces. Rectifying these injustices is a major focus of current urban planning, and this research contributes to that goal by identifying relationships between the socio-demographic characteristics of a neighborhood and the history of its forest patches. To do this, we compared the distribution, species composition, and structure of forest patches to census-derived socio-demographic data. We first identified forest patches across the Chicago Metropolitan Region using a morphological spatial pattern algorithm on a 1 m resolution tree canopy layer. Then, we characterized each patch’s development history by comparing them to pre-settlement (circa 1840) and 1940s forest maps. To quantify species composition in these patches, we sampled 120 plots and found that development history was a good predictor of forest composition, with remnant forests having more native and fewer invasive species than patches that experienced past clearings. Additionally, analysis of aerial LiDAR showed that remnant forests had more complexity and were less dense than other patches. Further, we found that LiDAR could be used to characterize patch history in lieu of historic maps, making this process scalable to other regions. Finally, we compared the distribution and history of forest patches to socio-demographic data and found that minoritized communities had less forest cover near them, and that the patches that were near them were more likely to contain shrubby, invasive species and to be denser. Forest patches are important providers of ecosystem services—spending time in them has been found to reduce stress and to improve impulse control and cardiovascular health. However, people need to directly interact with forests to receive these benefits, and the dense structure and low diversity may make the forests that under-resourced communities are near less pleasant to visit. These results indicate a need for the protection of remnant forest patches, but also for increased management of existing patches and intentional afforestation projects in under-resourced communities to improve equitable access to forests and their associated ecosystem services.