USDA Forest Service

Pacific Southwest Research Station

Pacific Southwest
Research Station

800 Buchanan Street
Albany, CA 94710-0011
(510) 883-8830
United States Department of Agriculture Forest Service. USDA logo which links to the department's national site. Forest Service logo which links to the agency's national site.

Publications and Products

Title: Effects of street tree shade on asphalt concrete pavement performance

Authors: McPherson, E.G.; Muchnick, J.

Date: 2005

Source Journal of Arboriculture 31(6): 303-310

Abstract: Forty-eight street segments were paired into 24 high-and low-shade pairs in Modesto, California, U.S. Field data were collected to calculate a Pavement Condition Index (PCI) and Tree Shade Index (TSI) for each segment. Statistical analyses found that greater PCI was associated with greater TSI, indicating that tree shade was partially responsible for reduced pavement fatigue cracking, rutting, shoving, and other distress. Using observed relations between PCI and TSI, an unshaded street segment required 6 slurry seals over 30 years, while an identical one planted with 12 crape myrtles (Lagerstroemia indica, 4.4 m [14 ft] crown diameter) required 5 slurry seals, and one with 6 Chinese hackberry (Celtis sinensis, 13.7 m [45 ft] crown diameter) required 2.5 slurry seals. Shade from the large hackberries was projected to save $7.13/m² ($0.66/ft²) over the 30-year period compared to the unshaded street.

Keywords: Avoided repaving costs, pavement distress, tree benefits, urban heat island

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    McPherson, E.G.; Muchnick. J. 2005. Effects of street tree shade on asphalt concrete pavement performance. Journal of Arboriculture 31(6): 303-310.
Last Modified: July 16, 2020