Measuring landscape change, lot by lot: Greening activity in response to a vacant land reuse program

Urban vacancy is a persistent problem in many cities across the U.S. and globally. Vacant land greening helps improve neighborhood conditions and initiatives that transfer vacant lots to neighborhood residents can return benefits to where they are most needed. We examined one such initiative, the Chicago Large Lot Program, which allows property owners in high-vacancy areas to purchase 1–2 city-owned vacant lots on their block for $1 each. We developed a fine-scale landscape change analysis based on a visual assessment of aerial and street-level imagery. Our assessment, which included 20 different aspects of land/tree cover and condition/care, was applied to 424 lots purchased in two areas of the city one year before and after purchase. Among the significant changes we observed was an 8% increase of lots with gardens, and while there was a 16% reduction of lots with mature trees, it was accompanied by a similar increase in the proportion of mature trees in “good condition.” Also, nearly a third of the lots showed signs of appropriation for use and/or stewardship prior to purchase, a process known as “blotting.” We found that transfer of ownership to residents through the Large Lot Program was followed by improved condition and care regardless of prior blotting, but the non-blotted lots had bigger improvements in condition and care after purchase than the blotted lots. Changes associated with vacant land greening have both social and ecological implications, and we discuss our findings with respect to urban greening strategies and future research.