Street trees have a woefully understaffed marketing department. They just can’t seem to get the message out, which is surprising since trees usually leave (leaf?) a money trail everywhere they go. In spite of this, city budgets for forestry related work have declined by 1/3rd in the last few decades. (1)
Trees add value in many ways – they increase the social value of the city by making places more pleasing to people on foot and in cars, and they also add great environmental benefits. Both fuel the enormous economic benefits that can’t be ignored.
The US Forest Service has assessed the economic value of the environmental benefits of trees with a tool they call iTree. This tool considers the storm water interception provided by trees that reduces downstream flooding control measures, energy conservation provided by shade, air pollution removal and carbon dioxide storage.
An iTree assessment of a Kansas City 30”oak street tree provides $167.48 annually in environmental benefits alone. A California study showed their 9.1 million street trees removed 567,748 on CO2 annually, which is what 120,000 cars produce annually. Those same trees intercept over 6.9 billion gallons of rainfall, remove 2,658 ton of air pollutants and save $101.15 million in energy costs each and every year.
Property values can be heavily influenced by the presence of street trees. Houses on a well-treed street have an estimated increase in value of $8,870 each, and a reduced time on the real estate market by almost 2 days. (2) Even just one street tree can add an average of $12,828 combined to the properties within 100 feet. (2)
In Portland, street trees add a total of $1.1 billion dollars in property value, or $45 million annually. (2) This added value is a huge benefit to the city because it increases property taxes. Portland’s example should bring an additional $15.3 million annually in property tax revenue
In a University of Washington study, consumers consistently rated shopping districts with ample trees as very positive compared to similar shopping districts without trees. They also reported to be willing to pay 11% more for goods and more for parking in treed shopping districts. That number increased to 50% for certain types of convenience goods. (3) Of course, this translates into a matching increase in sales tax revenue.
There are other street tree benefits that are hard to put a monetary value to. These additional benefits include:
- The public realm is more likely to be used as a social space because of the increased comfort created by trees, which encourages stronger social relationships. (4) An active public realm results in more connected citizens, which has both social and economic benefits.
- Health is increased due to more physical activity and cleaner air. In addition, views of nature have been proven to improve health. (5)
- Cars travel slower and more carefully on treed streets. (6)
- Lower violent crime (15%) and property crime (14%) has been attributed to streets with a good tree canopy. (7)
One common argument often pitted against street trees is the damage they cause to curbs or sidewalks. And while damage may eventually occur, the frequency is often over-exaggerated, and it is only after providing years or decades of all of the value that is documented above. What’s often missed is that a shaded street lasts longer. A Modesto, CA study found that over 30 years, a non-shaded street requires 6 slurry seals, but a well shaded street only needs 2.5 slurry seals. This shade was worth $0.66/sq. ft., and total street repaving costs are reduced by 58%. (8)
How does one 30” caliper oak pay out (annually)?
- Carbon Dioxide Removal (iTree) $10.07
- Energy Usage Conservation (iTree, assumes a street tree SW of home) $39.96
- Property Value Increase: $999.65 (average 13 year home ownership) + $12.15 taxes (assume 1.22% property taxes)
- Retail Sales Increases: 11%-50% increase revenue and sales tax (not measurable in this example)
- Increased health, safer streets & lower crime (unmeasured)
- Street maintenance savings $35.21 (assuming half of savings goes to curb & walk repair)
Total measured annual benefit of that one street tree is $1214.49
A California study also found that the state’s street trees provide annual monetary value of $1.0 billion. That’s each and every year! The same study suggests that only about 1/3rd of the possible street tree locations are filled, leaving opportunities for 16 million additional street trees in that state, or another $2.0 billion.
Conservatively, $5.82 in benefit is created for every $1 spent of street tree management. (1) We are leaving a huge pile of cash behind by not maximizing the benefits of street trees in our communities.
Perhaps the street tree marketing department can use this information to enrich cities that heed the message.
What do you think the biggest benefit of street trees are? Leave us a comment in the box below.
-The Kansas City Planning Studio of Gould Evans
- McPherson, E. Gregory; van Doorn, Natalie; de Goede. Structure, function and value of street trees in California, USA. Urban Forestry & Urban Greening 17, 104-115
- Wells, Gail. 2010. Calculating the green in green: what’s an urban tree worth? Science Findings, U.S. Department of Agriculture, Pacific Northwest Research Station
- Wolf, K. 2003. Public response to the urban forest in inner-city business districts, Journal of Arborculture 29(3) pp 117-126
- Taylor, AK; Kuo, FE; Sullivan, WC. 2001. Coping with ADD – the surprising connection to green play settings in environmental behavior 33(1), pp 54-77
- Wolf, K. 1998. Urban nature benefits: psycho-social dimensions of people and plants; University of Washington College Resources, Factsheet #1
- Dumbaugh, Eric. 2005. Safe streets, livable streets: a positive approach to urban roadside design
- Gilstad-Hayden, Kathryn; Wallace, Lori R.; Carroll-Scott, Amy; Meyer, Spencer R.; Barbo, Sarah; Murphy-Dunning, Colleen; Ickovics, Jeannette R. 2015. Research note: greater tree canopy cover is associated with lower rates of both violent and property crime in New Haven, CT
- Center for Urban Forest Research, Pacific Southwest Research Station. Why shade trees? The unexpected benefit