University of Maine researchers are studying the most efficient way to commercially thin regenerating clearcuts from the spruce budworm outbreak of the 1980s that are starting to reach profitable size throughout northern Maine. With no consensus among foresters and those in the logging industry about how best to thin stands, the researchers are investigating commercial thinning treatments that are silviculturally effective.
Jeffrey Benjamin, associate professor of forest operations, and Robert Seymour, the Curtis Hutchins Professor of Forest Resources, teamed with Emily Meacham, now with American Forest Management, and Jeremy Wilson, executive director of the Harris Center for Conservation Education, to compare thinning methods.
In the team’s recent study, they compared two whole-tree and two cut-to-length systems in terms of residual stem damage, retention of downed woody material, product utilization and production cost. While initial results were mixed in terms of residual stand damage, more than four times more biomass was produced from the whole-tree operations. The study also found commercially available equipment can conduct these treatments with skilled operators, but at a high production cost. The best system silviculturally was also the most expensive.
The researchers say efforts to develop cost-efficient harvesting machines to treat the stands should continue. No matter what technological advances are made, logging contractors carry the biggest responsibility for success because they need to balance residual stem damage and crop tree selection with production costs, according to the researchers.
Details of the study were published in the December 2013 issue of the Society of American Foresters’ Northern Journal of Applied Forestry.