WEAI/AERE 2009 - Individual Paper Abstract
Title: Valuing Vegetation in an Urban Watershed
Author(s): Noelwah R. NETUSIL, Reed College,Portland, OR 97202-8199, USA, netusil@reed.edu, (503)517-7306; Jonathan Kadish, Pomona College; (picture credit: Balsam Root, Wind Mountain; Alex Montgomery via Noelwah Netusil)
Abstract: This study uses the hedonic price method to estimate how land cover types--trees, shrubs, water, and impervious surface areas--on and surrounding single-family residential properties in Portland, Oregon are related to their sale price. The study area is characterized by poor water quality due to its high concentration of impervious surface areas (roofs, parking lots, streets, etc.) and a combined sewer system that periodically discharges untreated waste into the Willamette River. Encouraging homeowners to increase vegetation on their property may help mitigate this problem--studies show that natural landscaping can reduce stormwater runoff by as much as 65% while also reducing pollutants such as nitrogen, phosphorous and heavy metals (Environmental Services 2006). However, the existing literature (Acharya and Bennett, 2001; Des Rosiers et al., 2002; Geoghegan et al., 1997; Mansfield et al., 2005) shows mixed results for the relationship between vegetation and property values. We investigate the relationship between vegetation and property values using spatially referenced single-family residential property sales from January 1, 2005-December 31, 2007 and land cover information on the percentage of trees, shrubs, water, and impervious surface area on each property and within 200 feet, 1/4-mile, and 1/2-mile buffers of each property. Results using a semi-log functional form suggest that vegetation within 200 feet, 1/4-mile, and 1/2-mile buffers of a property contributes positively to price, while the effect of vegetation located on the property produces mixed results.