One aspect of modern urban forestry and arboriculture is that of the cost benefits that urban trees provide for people and the environment. In the 1980’s and 90’s (and in some cases earlier), several non-profit project groups, along with a few large metropolitan municipalities and pioneering scientists and researchers, spearheaded a movement of quantifying and accounting for tree cost benefits in and urban environment. The research goal was to identify, quantitatively, what the return was on investing in a tree. Arboriculture specifically, once branded in the early twentieth century as a concept and commodity of proper care, at the end of the century shifts to an industry with an active environmental role on the cutting edge of technology, with deep political ties and the potential to create a green infrastructure with a diversity and function like never before.

The major players in this story, highlighted in Jonnes book Urban Forests that I’ve been referencing in past posts, are Edith Makra, Rowan Rowntree, Gregory McPherson and David Nowak. Together, in the city of Chicago, they would converge by way of Makra’s orchestration to work together on a government funded project known as the Chicago Urban Forest Climate Project.

“The EPA was still pushing the city [Chicago] to address its air pollution issues, and in search of a solution, Mayor Daley asked Makra to investigate whether trees could actually help clean the air, as well as prevailing on a fellow tree lover in Congress, twenty-term Democratic Chicago representative Sidney R. Yates, to earmark some serious federal research dollars for the problem. (Yates, who was chair of the Interior Committee, was the same politician who had refused to let President Reagan kill the federal urban forestry program.” (Jonnes, 197)

Makra got Rowntree, and Rowntree got McPherson and Nowak, who were both currently researching monetary cost benefits of planting, watering and air filtration capacity, and developing things like “an algorithm that would work for each species to know it’s crown leaf area in relation to its trunk size” (201) in order to identify air pollutant removal capabilities between specific species of trees.

The Dream Team.

Jonnes writes of the grounds of the North Park Village Nature Center, the base anchor of the Chicago Urban Forest Climate Project:

“The surrounding 158 sylvan acres had been the site of the Chicago Municipal Tuberculosis Sanitarium from 1911 to 1979. ‘At lunch,’ recalls McPherson, ‘we used to go out and play Frisbee golf. There was this enormous park space, and we had fun just wandering around under these big old massive oak tree predating the Cival War’.” (Jones, 201).

When the final report was written, chapters had titles like “The Role of Vegetation in Urban Ecosystems”, “Energy-Saving Potential of Trees in Chicago”, “Air Pollution Removal by Chicago’s Urban Forest”, “Urban Forest Structure: The State of Chicago’s Urban Forest” to name a few. Not only was this research simply looking at trees themselves as systems, but as individuals within a greater network of systems, populations and infrastructure.

These positive environmental impacts that trees have are mainstream marketing now: they clean the air, they manage storm water runoff, they lower the temperature of urban heat islands, they filter particulate matter out of the air, and they provide habitat for wildlife and microorganisms, and mediate microclimates in tiny pockets of even the largest urban machines. They also provide physiological and political benefits in the communities where they reside. Everyone loves a politician that loves trees, or a long walk in the park. Trees have been known to calm individuals, to organize and strengthen communities, revitalize cities, inspire and educate youths, create jobs and ignite promise for the future.

This communal value that we see in the tree as a part of the urban forest is a direct result of the work of projects like the Chicago Urban Forest Climate Project, and earlier ones like the Dayton Climate Project. Quantifying tree value mathematically, given its geometric dimensions and biological processes, modern technology shows us that on paper, trees really do change the world. It’s not just an Arbor Day celebration anymore. There is a real sustainable vision rooted in urban planning that prioritizes a healthy urban forest, a natural resource that that is the lifeblood of healthy urban environment.

Now, tree care was becoming a super power. In the twilight of the twentieth century, arboriculture and the urban forest prove to be a green backdrop for the age of technology. Finally, we learn that trees don’t just make people happy, or make people money. They also save people money.

What better investment than that?