Field Note - Poplars With Purpose

At a glance, the rows of poplar trees behind the Science Museum of Minnesota and the District Energy St. Paul Inc. plant appear to be a typical urban hedge separating two downtown businesses.

But the 100 poplars provide more than shade and a natural partition, according to Patrick Hamilton, director of environmental sciences for the museum. They also draw attention to District Energy plant efforts to reduce waste and pollution by using wood to produce heat and electricity.

The trees, which are a fast-growing hybrid variety, were planted in 2000 and will reach a height of 20 to 25 feet before they are harvested in 2005. They attract museum visitors to a series of interpretive panels explaining the District Energy biomass plant, which provides electricity to Xcel Energy and hot and cold water for heating and cooling to downtown St. Paul buildings, including the museum. When harvested, they will be chipped and used as fuel for the plant.

The biomass plant is designed to burn up to 280,000 tons of untreated waste wood (free of paint, glue, or other additives) per year. The wood comes from public and private suppliers, including municipalities, wood-products manufacturers, and tree trimmers. The plant became fully operational this past May.

Anders Rydaker, president of District Energy St. Paul, said the plant’s cleaning process keeps emissions 99.99 percent free of particles, which is much better than coal-fired power plants and home wood-burning.

Jean Mouelle, a DNR wood utilization and marketing specialist who helped with the poplar planting, said burning waste wood "also reduces the amount of wood that gets into landfills or is dumped or illegally burned each year in the Twin Cities area."

Jason Abraham