Merit Award -- Research
The Effect of Open Space Preserves on Residential Property Values
Jack Gilcrest, ASLA
4015 N. 78th Street
Scottsdale, AZ 85251
Statement of Purpose: Can we balance the need for urban development and land conservation? These two land use decisions are often considered to be mutually exclusive. The premise of choosing one over the other continues to polarize debates regarding land use. Anecdotal evidence suggests open space can have a positive effect on the value of adjacent developed lands, especially residential. Literature review reveals this relationship has been studied in the United States as well as internationally. The objective of this study was to determine if this positive relationship was evident in Phoenix by investigating the effect of Phoenix's existing open space preserves on residential property values. Two of Phoenix's largest open space preserves, South Mountain Park (16,500 acres) and Phoenix Mountains Preserve (7,500 acres) were utilized as an urban laboratory for the analysis. Three representative areas adjacent to the preserves were selected as sample areas. Different characteristics or attributes contributing to residential property values were identified and were grouped into parcel, locational and neighborhood categories. Parcel characteristics were classified and mapped using Arc View software. A hedonic pricing model was used for the statistical analysis of all the characteristics. The study also applies the research findings to conceptual land use studies. A multiple edge' concept is presented as a technique for buffering and transitioning preserved open space from adjacent developed lands. The goal is to maximize the potential of the developed lands while protecting the ecological integrity of the preserved lands.
Community Context: The need for this study was identified during the planning of the city of Phoenix's new 20,000-acre preserve. The results of this study would help support the establishment of the preserve by documenting the positive effect of existing open space preserves on adjacent home values. The Master Plan for this preserve, referred to as the Sonoran Preserve, was awarded a President's Award of Excellence in the 2000 ASLA Awards Program. The Sonoran Preserve Master Plan was approved by the Phoenix City Council in 1998. A 10-year sales tax by the Phoenix voters was passed in 1999 and land acquisition is currently underway.
Role of Landscape Architect: A study was initiated while the landscape architect was pursuing a graduate study program. The landscape architect acted in a lead role in all phases of the study. The study was funded as a result of a proposal prepared by the landscape architect. The landscape architect developed a work plan and assembled a project team consisting of landscape architects, planners, economists, environmental scientists and GIS analysts. The landscape architect directed all aspects of the work and assisted in the GIS mapping and statistical analysis. The final report was prepared solely by the landscape architect including all figures, maps and text.
Special Factors: Descriptive information for each parcel within the sample areas was obtained from the GIS database maintained by the City of Phoenix. This database greatly facilitated the study. It was important to analyze a sufficient number of parcels to provide a sample size large enough for a statistically valid analysis. As a result, the total combined study area was almost nine square miles and included over 10,000 residential parcels. GIS proved to be an effective tool for creating the study database, performing the spatial calculations and preparing the classified maps.
Significance: This study supports the findings of similar studies conducted in other regions and countries by showing preserved open space can have a positive effect on residential property values. As expected the most important factors influencing residential property values were parcel characteristics such as size and age of the home. However, the locational attribute, proximity to the preserve boundary had a surprisingly strong influence on residential property value, greater than all other locational or neighborhood attributes analyzed in the study.
The study provides helpful information regarding the ongoing issue of balancing urban development and land conservation. Evidence is presented that preserved open space when properly planned and integrated with adjacent developed land uses can provide significant value to a community. This supports the philosophy that it's as important to determine what lands should be left undeveloped and set aside as preserved open space as it is to decide what lands to develop. The results of this study will be useful to landscape architects, planners and public officials involved in community development, growth management and land conservation efforts.