Researchers test biochar on Chicago trees

April 21, 2010 10:00:00 PM PDT
A type of charcoal first used centuries ago may be a key ingredient to helping reduce climate change.

Researchers from the Bartlett Tree Experts and the Morton Arboretum are conducting a joint study on biochar and urban trees.

"What we're doing here at this site is testing the effects of biochar on urban street trees," said Kelby Fite, Ph.D. , soil scientist, Bartlett Tree Experts. "This site, as far as we know, is actually the first site where it's been applied to urban street trees."

The researchers are applying various combinations of biochar and fertilizer to about 60 trees along Milwaukee Avenue in Wicker Park-Bucktown area.

"It's wood waste burned at very high heat without the presence of oxygen. So that keeps it from smoking and that turns it into something that is like charcoal," said Scott Jamieson, Bartlett Tree Experts.

The substance is a type of charcoal, but experts caution against raiding your grill to help your garden.

"With cooking charcoals, they are generally produced at a lower temperature so that means you have more volatile compounds left in the plant material and that could cause some problems with tying up nutrients in the soil," said Dr. Fite.

Studies on farm crops have shown significant growth. These researchers are hoping for similar results. The life span of so-called street trees is typically under 10 years.

"There's a lot of pollution. There's a lot of de-icing salts getting into our systems that aren't good. Soil can get impacted. People come out of establishments and dump all sorts of stuff into those pits. So, it's a very hostile growing environment," said Jamieson.

Some trees will also be treated at the Morton Arboretum where the growing environment can be controlled.

"In a greenhouse setting, we're looking at smaller trees, seedlings. And then in the nursery, we're looking at trees that will go in the landscape, so they're larger trees, five to eight foot tall," said Bryant Scharenbroch, Ph.D., urban soil scientist, Morton Arboretum.

The researchers plan to monitor the trees for at least the next two or three growing seasons. If they find that bio-char has a significant impact, they believe it could help address issues including climate change, water pollution and food insecurity.