Bridging the land use gap: Examining tree canopy cover and connectivity by land use in 10 U.S. cities

Abstract

Areas of high tree canopy cover, especially connected tree canopy cover, provide habitat to support biodiversity and cooling to ameliorate the urban heat island effect. However, the nature-based solutions provided by trees are not distributed equally; land use contributes to this systematic inequality because the places where it is easiest to plant trees are often not where trees are needed most. To better understand the gaps and opportunities for tree planting across the urban landscape, we examine the distribution of tree canopy cover and connectivity by land use in 10 U.S. cities. We find that parks have the greatest tree canopy coverage followed by single-family residential areas, multi-family residential areas, and industrial land uses. On average, single-family neighborhoods had 8.5 % points more tree canopy coverage than multi-family neighborhoods, with gaps as high as 18.6 % points. Looking at the size of connected tree canopy, we find that residential land uses are home to more small contiguous tree canopy patches (>1 ha in area), while parks have more large contiguous tree canopy (>12 ha in area). We compare the contiguous tree canopy findings to tree planting policy in each city to examine the influence of intentional planning for tree connectivity, and close with policy-oriented implications of our results. Namely, we suggest: 1) closing the gap between single-family and multi-family tree canopy cover, 2) factoring connectivity into tree planting and preservation, and 3) taking a context-specific approach to increase tree cover in industrial areas in order to more equitably distribute the climate, ecological, and health benefits of trees.