Quantifying the aesthetic benefits of urban forestry

Abstract

All the usual methods for valuing non-market benefits and costs may be applied to the aesthetic values of urban trees. However, evaluation has most usually been undertaken by one of two apparently dissimilar methods. The expert approach uses a mixture of measurement and judgement. Different versions of the approach have different quantitative input, produce divergent results, and theoretical justifications of their cash value are lacking. The hedonic approach attempts to derive cash values from house prices. Here too problems of quantification arise, in choice of appropriate variables, in the form of relationships and in interaction of variables. An approach using the human eye's ability to synthesise disparate variables may overcome these problems, but there remain problems of collinearity between environmental and demographic variables. At least explicit recognition of judgement in the process allows open discussion of these problems.