Committee drafts woody biomass harvesting guidelines

By Jessica Ebert
In 2005, the Minnesota legislature passed a mandate requiring the Minnesota Forest Resources Council (MFRC) and the Minnesota Department of Natural Resources to develop guidelines for the sustainable harvest of woody biomass from forests, brushlands and open lands.

A "confluence of interest" in biomass-to-energy production spurred the legislative order, along with increasing energy prices and state-supported incentives for renewable energy production. Also, an agreement was recently signed by the city of Hibbing, Minn.; the city of Virginia, Minn.; and Xcel Energy in which the two communities will supply Xcel Energy, a leading utility, with energy from woody biomass, explained Dave Zumeta, executive director of the MFRC. In response, the two state agencies appointed a 12-member technical committee comprised of soil scientists, wildlife biologists, forest managers, loggers and others to develop the guidelines based on existing timber harvesting and forest guidelines, and a worldwide literature review compiled by researchers at the University of Minnesota. The new, voluntary guidelines were approved by the committee May 16, and final documents will be publicly available this month.

Woody biomass provides a habitat for microbes, insects, birds and animals; filters water destined for wetlands and other bodies of water; and provides nutrients to the soil. The general aim of the committee was to provide guidelines for how much woody biomass can be removed from forests and other grasslands without negatively impacting wildlife and plant diversity, water quality, and soil productivity. Although the report presents numerous guidelines, the main recommendation on a given site is that one-third of the fine woody debris-the tops, limbs and woody biomass that measures less than six inches at the large end-be retained. This is the equivalent of leaving one out of every five average-sized trees in a particular area.

"I do see a lot of potential through biomass harvesting to improve forest management," said Dean Current, program director for the University of Minnesota's Center for Integrated Natural Resource and Agricultural Management. "We need the guidelines to make sure it's done in an environmentally sustainable way."

The new guidelines have generated nationwide interest, Zumeta said. "This hasn't been done before," he told Biomass Magazine. He cautions that the guidelines are just a first step. "There are a lot of research questions that need to be addressed," he said. Over the next few years, the implementation and effectiveness of the guidelines will be monitored so that revisions can make the guidelines more focused. "This is a first cut at it, and we'll improve them down the line," Zumeta said.