Guest blog by Kathleen L. Wolf, PhD, a research social scientist at the University of Washington, Seattle. More information about this and related studies can be found at the Human Dimensions of Urban Forestry and Urban Greening website. The USDA Forest Service has been a major sponsor of this research.
Trees make city streets more beautiful. But are improved aesthetics the only benefits that trees provide in a community? Recent research shows that people’s reactions to trees can have positive effects on everything from the market value of homes to traffic safety.
One of the most little-known facts about trees’ effects is the importance of their impact on central business districts. Downtown districts are the places where small businesses meet the everyday needs of nearby residents, and are the soul of a community. They significantly contribute to the local economy and provide jobs. Trees help make these places more welcoming and appealing.
I have worked with communities throughout the U.S. to do research studies on how consumers respond to business districts that have a quality urban forest canopy. Some studies have involved big cities, others smaller communities.
The ways in which trees and other urban greenery affect shoppers is subtle, but the outcomes are all about the bottom line. Below is a summary of what we’ve learned.
The Psychology of Shopping
There is a good bit of retail research about how the store environment affects a person’s shopping behavior. Most of these ‘atmospherics’ studies focus on reactions to the interior of stores—testing how shoppers respond to things ranging from the brightness of lighting to how goods are organized and presented. But we have learned that consumers are influenced long before they ever enter a store. First impressions about a business start at the curb and sidewalk. The character and quality of a streetscape can affect the appeal of a business district and visitors’ buying behavior.
During this recession, many consumers are being careful with their spending, but they still shop. Retail research has taught us that people seek positive experiences when shopping.
The decision to shop for shoes, for instance, is not simply about finding the product in the most efficient way, but is much more complex. For example, people enjoy socializing so they might bring along friends and family in their search for the perfect shoe. The physical qualities of a shopping setting—and whether those make for a pleasant social outing or not—can directly affect sales.
Studies Show: It Pays to Invest in Trees
Our studies assessed how trees influence shoppers’ perceptions in various retail settings, from the central business districts within several large cities to smaller main street malls. The findings were remarkably consistent.
When comparing similar places, some having trees and some not, trees elicited positive reactions from customers. We used surveys to test responses and were careful to present images of settings having the same level of building care and street tidiness.
First, judgments of product value, product quality, and merchant responsiveness were more positive in places having trees. People infer that they will have better experiences in more attractive settings.
Second, people claimed they were willing to travel more often, for more time, and over greater distance to a retail district having trees. This means that a district having a quality urban forest may attract visitors over greater distances, boosting the number of possible customers.
Third, visitors said they would spend more time in those districts with trees once they arrived. Customers were also willing to pay more for products and services, by up to 9% in the smaller communities and up to 12% more in districts within larger cities. People even claimed that they’d pay more for parking.
Planning, planting, and the maintenance of trees are real costs. But, this finding suggests that those expenses may be offset by the additional revenues they help bring in.
Despite demographic differences among participants, the consistency of responses across all studies was remarkable. Whether the studies compared the size of the city where people lived or their household income, research subjects consistently preferred green shopping districts.
Harvesting the Benefits of Trees
Some of our surveys were done with businesspeople. They generally rated the value of tree benefits lower than shoppers do, suggesting some merchants may be unaware of how trees affect consumer behavior. That’s unfortunate since even a modest investment in the planting and maintenance of trees along a streetscape could make a positive difference to a small business district.
But, it’s never the responsibility of business owners alone to make their business district greener. Trees need help to thrive in the urban environment! A comprehensive plan is critical to a successful downtown greening. Good planning leads to landscaping that can create positive experiences—in part because a plan helps garner support from community members, boosts fundraising, and ensures that details are thought through. A plan also prepares the way for ongoing maintenance over the decades-long lives of trees. Healthy trees maximize benefits and reduce costs.
Local businesspeople can and should be champions for trees—after all, big trees improve wealth and health—for neighbors, employees, and customers. The effect trees have on the customer experience is just one more example of how trees tap into the deep appreciation that many people feel for nature and its numerous benefits. Some benefits may be unexpected and some may be subconscious; but they’re all worth investing in.
 Kathleen L. Wolf, “Trees in the Small City Retail Business District: Comparing Resident and Visitor Perceptions,” Journal of Forestry 103, no. 8 (2005): 390-395; Kathleen L. Wolf, “Business District Streetscapes, Trees, and Consumer Response,” Journal of Forestry 103, no. 8 (2005): 396-400.
 Paco Underhill, Why We Buy: The Science of Shopping (New York: Simon & Schuster, 1999).
 L.W. Turley and Ronald E. Milliman, “Atmospheric Effects on Shopping Behavior: A Review of the Experimental Evidence,” Journal of Business Research 49 (2000): 193–211.
 B.J. Pine and J.H. Gilmore, The Experience Economy: Work Is Theatre and Every Business a Stage (Boston: Harvard Business School Press, 1999).
 In each study, a sample frame of potential shoppers was identified within close geographic range of study sites. Surveys were distributed by random sampling using commercial mailing lists or sidewalk intercepts. Response rates ranged from 10 percent to 80 percent across studies. Large cities studied were neighborhood districts of Los Angeles, Washington, Chicago, Portland, Pittsburgh, Austin, and Seattle. Athens, GA was the only midsize city. There were also 14 small cities, distributed among seven states.
 Participants were asked to respond to perceptual verbal items using rating scales and to indicate likely patronage behavior within categorical indicators of time and distance.
 The urban forest is a public good. As such, it rarely generates tangible products that can be bought and sold. Economists utilize several strategies, including contingent valuation methods (CVM), to value nonmarket goods and services provided by nature and ecosystems. CVM surveys have been used to assess public “willingness to pay” for use, conservation, or restoration of natural resources.