ABSTRACT
In urban areas the landscape consists of a mix of built-up areas and open spaces. These open spaces surround, intrude and perforate the urban fabric and contain many societal values: agricultural areas produce food; parks and sports grounds offer opportunities for recreation; and natural areas contain ecological values. In fact, most open spaces offer several values simultaneously: natural areas, for example, can also be important for recreation or the infiltration and storage of rain water, while agricultural land can be of high ecological value and offer recreational opportunities. These many additional values of open space are not generally acknowledged, which may be partly due to the lack of a clear price. Not having an obvious monetary value makes green, open areas vulnerable to construction activities and infrastructure. Such use of open space entails the imposition of externalities of certain actors on others, but since the market value of open space does not fully reflect its societal value, these externalities are market failures that call for corrective measures by the public sector in the form of land-use interventions or pricing measures. Incorporation of the public interest in open space in planning requires quantitative valuation of this asset. This can help policy makers improve their decisions. The difficulty with this is of course that environmental and general societal values are normally not traded, and hence no market price can be observed that would reflect or approximate marginal costs or benefits.
