Milwaukee Ave. trees part of scientific experiment to improve urban forests


David Ginople, WPB Chair, explains that this bare tree is one of the youngest on Milwaukee Ave.

The selection of Milwaukee Ave. as the site for a scientific experiment regarding the health and maintenance of urban forests was the convergence of goals, projects, groups and individuals.

Though one may not think of a city as having a forest, they do and they are important. They provide among other things  a natural cooling for neighborhoods and homes; they filter the air; they reduce rainwater runoff which effects flooding; and they add ambiance.


Ginople points out the importance that trees be suitable for the district -- drought, disease, salt tolerant

Being a city tree is not an easy job. They grow in tightly confined spaces in soil that can be as hard as concrete. They get limited water and nutrients.  In winter, they get a diet high in salt. Their life expectancy averages ten years because of these environmental stresses.


Providing shade and less heat for the pedestrian, this tree is one example of urban forest benefits

In 2007, the WPB, Special Service Area (SSA) #33, completed a tree inventory, documenting the species, size and condition of every tree on the SSA streets. Of the more than 1,100 trees in the district at the time, ninety-eight needed replacement.  Though WPB reached out to the Alderman's office to assist in this project, it turned out that the City was in the midst of a Green Street project which hired the Seven-D Construction  company to plant trees throughout the city. Thus, some of the trees were replaced. To date not all have been replaced and there is a moratorium placed on plantings. The City's involvement in tree planting and maintenance is that it plants a tree, waters it once and guarantees it for one year. Beyond that, the tree is on its own.

Understanding the forest situation, WPB's  Clean, Green and Safe Committee began addressing issues around trees and how to  maintain those in the SSA area. In January 2010, Erik Grossnickle, a certified arborist with Bartlett Tree Experts, joined the committee and began educating people on the issues around urban forests. In addition they worked with the City, the Department of Forestry and the City's SSA management team.


Researchers drilled a grid into the soil of each tree pit, to be filled with biochar, biochar and fertilizer or just fertilizer*

Early this year, Scott Jamieson, a Vice President of Bartlett Tree Experts, was talking with Kelby Fite, one of Bartlett's scientist in their research lab in Charlotte, NC, about an investigation they were engaged in with The Morton Arboretum. They were looking at the possibility that a type of charcoal called biochar (a soil amendment) could help make street trees' lives easier, resulting in healthier, fuller trees with a longer life expectancy. The investigation led to a plan for an experiment that required finding a test site.

They looked at several possible locations but could not find one that met all their criteria which included: a mix of specific species with multiples of each, no grates over the tree base and no gravel sub strata. Then Jamieson, in his personal time, came to Wicker Park. He saw Milwaukee Ave. and contacted Fite. Knowing that Grossnickle was involved with the WPB, the idea of having Milwaukee Ave. as an experimental site was brought to the commission.


Elden LeBrun, Bartlett's Labs, drills, Bryant Scharenbroch, The Morton Arboretum, backfills and Fite mixes in the biochari*

Fifty-six trees between Concord and Paulina have been selected and tagged. The control groups will be those receiving biochar, fertilizer, combination of biochar and fertilizer or a control. Part of a comprehensive management plan, the experiment will be run over a three-year period during which six arborists will observe and run tests three or four times. Biochar is the result of heating recycled plant material at high temperatures. It's been used for centuries to restore infertile soils. While used on food crops successfully, it is not known whether trees will benefit from its use.

If it does work, it has the potential of delivering nutrition to the soil for 100 years. It can save cities and property owners in tree-replacement costs and maintenance while producing healthy trees that benefit the environment and all those who inhabit it.


Process is finished by raking over the soil*

"Kudos to the neighborhood for allowing this experiment to happen," says Grossnickle. "Typically when we find a site, the locals want the trees treated but they don't want the research. Often that is because they want all the trees treated the same." (This, of course, would make an unscientific experiment!) "It is awesome to work with a progressive group like the WPB."


NOTE: This WPB activity falls under one of the commission's seven implementation goals. According to their Master Plan, "Greenifying is about becoming an environmentally sound and ecologically sensitive community not only in ideas and ideals but in practice and on the ground -- about altering habits at the individual scale and investing in landscapes at the neighborhood scale to allow WPB to evolve as a sustainable and lush urban district."

*Photos courtesy of Terracom Public Relations for Bartlett Tree Experts



More information on biochar research and the urban forest

More information on research related to biochar and the urban forest can be found at

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