Linking tree cover change to historical management practices in urban parks

Keywords: urban tree cover, urban forest, urban park, urban disinvestment, aerial imagery, landscape history
Session Type: Virtual Paper Abstract
Day: Friday
Session Start / End Time: 2/25/2022 11:20 AM (Eastern Time (US & Canada)) - 2/25/2022 12:40 PM (Eastern Time (US & Canada))
Room: Virtual 40

Abstract

Urban parks provide critical ecological, health, and social benefits and constitute a substantial proportion of urban tree canopy (UTC) within a given city. As cities set ambitious UTC targets, it is critical to understand the drivers of past UTC changes in parks. We sought to uncover specific historical events and social processes impacting park UTC in a post-industrial city that experienced substantial population loss and urban park disinvestment since 1950, and is currently undergoing an urban forest strategic planning process. Our mixed-methods approach involved quantifying spatiotemporal UTC changes and connecting those changes to historical management practices for three parks in Philadelphia, PA (US). We delineated UTC using aerial imagery spanning 59 years (1959, 1980, 2000, and 2018), and synthesized information from archival records and discussions with park staff about historical management practices. We found substantial UTC gains between 1959 and 1980, due to both: (a) budget cuts, mowing cessation, and associated unintended forest emergence; and (b) purposeful tree planting and reforestation activities. Contrary to literature suggesting that financial investment would lead to UTC gain, we saw declining UTC following an influx of new funding post-2000 due to construction and ecological restoration. Across the three parks, differing pathways led to convergent outcomes of UTC gains, even though past management goals were not actually focused on UTC. Our work suggests that landscape management and UTC goal-setting could benefit from an improved understanding of how historical processes impact land cover.