Open space provides a range of benefits to citizens of a community, beyond the benefits that accrue to private landowners. Parks and natural areas can be used for recreation; wetlands and forests supply storm-water drainage and wildlife habitat; farms and forests provide aesthetic benefits to surrounding residents. And in rapidly growing urban and suburban areas, any preserved land can offer relief from congestion and other negative effects of development.
It is one thing to recognize that open space provides these benefits but quite another to place a monetary value on them. To make important policy and planning decisions about zoning, restrictions on land use, government purchase of lands for parks, and similar initiatives, however, estimates of preferences and even dollar values can be essential.
In The Value of Open Space: Evidence from Studies of Nonmarket Benefits, Virginia McConnelland Margaret Walls review more than 60 published articles that have attempted to estimate the value of different types of open space.
The two major approaches for estimating open space value from the economics literature are the focus of this study: revealed preference methods and stated preference methods. In the first category are hedonic property value studies in which the open space value is inferred by estimating the sales price or value of a property as a function of measures of proximity to open space and other property and neighborhood characteristics. In the second are studies that use carefully designed surveys to elicit preferences or values households place on various types of open space amenities. Both contingent valuation and contingent choice studies are reviewed.
Both the revealed and stated preference studies generally show that there is value to preserving most types of open space land uses, but the values tend to vary widely with the size of the area, the proximity of the open space to residences, the type of open space, and the method of analysis. One conclusion drawn from this review is that the value of open space amenity estimates, even for specific types of open space, appear to be quite site or location specific.
However, it is possible to draw conclusions from the range of studies about the direction of particular effects, how values vary by location and other influences, and the differences among the methodologies used to estimate values. In addition, McConnell and Walls suggest areas where additional research is needed to improve valuation estimates. They also conclude that more analysis is needed about how to conduct studies with broader applicability.