This question was just considered by the NC Utilities Commission which concluded that yes, whole trees count as a renewable energy resource. The argument from those who oppose such a ruling is that counting whole trees as a renewable fuel would risk the state’s forests to over-harvesting. The N & O article, State: Whole trees count as renewable fuel, from October 11th, 2010 further discusses this ruling and its potential implications.
Pose this question to your students, divide them into two groups, one group in favor of whole trees counting as a renewable energy resource and the other group in favor of only wood waste like sawdust and other scraps counting as a renewable energy resource. Next, ask them to conduct research on the social, economic, and environmental consequences of their preferred biomass source (whole trees or wood waste) and come prepared to present their side and debate the issue.