- Coup, Charles E.
The Graduate School, University of Maine
In the Northeastern United States, re-emerging markets for renewable energy are driving interest in increasing the harvest of underutilized biomass material from Maine's forest. These markets may offer opportunities for forest managers to implement silvicultural treatments that have previously been foregone due to their high cost. However, many operational challenges arise in using current harvesting systems to harvest biomass material profitably while simultaneously achieving silvicultural objectives. This research uses a case study approach to analyzing some of the possibilities and obstacles in implementing biomass harvesting in Maine. The first three studies investigate a factorial silvicultural and operational case study involving whole-tree biomass harvesting in conjunction with herbicide injection. The first study investigated the use of combined biomass harvesting and herbicide treatment as a means of rehabilitating northern hardwood stands dominated by dense understory thickets of small diameter American beech (Fagus grandifolia Ehrh.) and striped maple (Acer pensylvanicum L.). Prior to being harvested, a portion of beech and striped maple trees were treated using glyphosate stem injection as a means of controlling post harvest regeneration. Efficacy of the herbicide treatment was evaluated the fìrst growing season after harvesting. During the harvest operation, a second study evaluated the productivity and impact of the feller-buncher using two trail spacings to determine if operational efficiency could be increased. A third study was carried out after the harvest to quantiflz and evaluate the damage inflicted by the operation at each trail spacing. A related case study was then conducted that attempted to develop an organized methodology for analyzingand improving the long-term efficiency of whole-tree harvest operations using statistical process control (SPC) in order to better evaluate the long-term impacts of modifying harvesting systems. The methodology was developed using actual operation data collected on several whole-tree system machines used throughout Maine. Results from the combined herbicide injection and biomass harvest case study indicated that whole-tree harvesting could utilize most of the beech and striped maple component of the stand while also effectively controlling the density of post-harvest beech regeneration. The harvest study found that feller-buncher productivity was not significantly different when operating at either of the two trail spacings; however, a tradeoff was found between efficient bunching and bunching frequency, with the narrower trail spacing using less time per bunch but requiring more bunches to be produced. Trail occupancy levels resulting from use of the narrower trail spacing were considerable, which could pose potential difficulties in future management. However, the frequency and patter of damage to the residual trees caused by the harvest operation was not significantly different between the two trail spacings. The second case study demonstrated that Statistical Process Control could offer a unique perspective on evaluating operational variability and showed great potential as a tool for improving forest harvesting processes. The study revealed several challenges in applying this approach to whole-tree harvesting operations. These challenges are primarily related to how operational data is collected and organized, and how the underlying causes of variation are interpreted.