Psychologists have debated the relationship of attitudes and behavior; both were explored in these studies. Respondents were asked to give projections of their behavior within the three hypothetical shopping districts, including travel time, travel distance, duration of visit, frequency of visits and willingness to pay for parking. On all categorical response scales, higher measures were reported in the districts having the presence of street trees. For instance, people are less willing to spend more time in unvegetated settings while greater visitation times are associated with the presence of green trees. The higher response (for settings with landscape improvements or green trees) may represent a threshold typical of local shopping areas. In addition, respondents claimed they would be willing to pay more for parking in a well landscaped business district.

This suggests greater revenues from shaded parking could offset the costs of parking space loss, a frequent objection to trees by merchants. The inverse response pattern was consistent across all patronage behavior variables. No green trees responses are concentrated at the low end of each of the variables' categorical arrays and diminish in frequency moving toward the high end of the arrays. Conversely, responses based on the presence of trees are less frequent at the lowest end of the arrays, increase in frequency, then slightly decline at the variables' higher value levels but remain at higher frequencies than the non-green settings.

Product Pricing

The bottom line is the top interest of most business people. Do trees influence how much people are willing to pay for goods? Contingent valuation methods were used to assess how natural amenities relate to customers’ price valuations.

Within each district shopping goods (e.g. watch, light jacket) mean values are greater than convenience goods (e.g. lunch sandwich, flower bouquet), with specialty goods (e.g. new glasses, art print) commanding the highest stated values. These pricing trends are consistent with marketing literature (Kinnear et al. 1995) in that the goods classes typically contain products of ascending value, quality and consequently, price.

Respondents reported willingness to pay less for equivalent goods in business districts without trees. Price differences between tree and no-tree conditions are considerable: approximately fifty percent for convenience, forty percent for shopping and thirty-five percent for specialty goods. Analysis using weighted standard scores across all products generated a more conservative 11.95% difference between tree and no-tree conditions. Given the low profit margins of most retail businesses, trees provide a significant “amenity margin.”