In northern Wisconsin, trucks and trains stacked with timber crisscross the region, an integral part of the economy. Mills often burn branches, bark, rotten timber and other woody "biomass" left over from logging operations to reduce energy costs. Some use hydropower, thanks to their position along the state's rivers.
As Wisconsin showed decades ago, the environmental and economic benefits of trees intersect. Trees, of course, provide a refuge for wildlife and serve as giant carbon sponges. Replacing trees that are thinned by logging can keep a forest young and healthy, less susceptible to forest fires. The logging, in turn, gives the owner an incentive to keep the land undeveloped.
"If you lose that economic value, there's less incentive to keep those lands forested," said Paul Delong, Wisconsin State Forester. "Suddenly, the incentive to keep that habitat healthy goes down."