Date of Award


Level of Access Assigned by Author

Campus-Only Thesis

Degree Name

Master of Science (MS)


Forest Resources


Jeffrey G. Benjamin

Second Committee Member

Steven Bick

Third Committee Member

Robert Rice


Interest in the use of renewable resources for the production of energy has increased greatly in recent years. This movement has driven the interest in using forest biomass as one of the sources of renewable energy. While this is not a new concept, originally developed during the oil crises of the 1970’s, many changes in the landscape and harvesting technologies have occurred since its inception. One inescapable issue faced by the forest biomass industry is the low value of the delivered product, making this a very cost-intensive industry. Therefore, understanding the cost of operating machines required to deliver these products to roadside, the productivity of the required comminution devices, and the quality of products produced by comminution machines is necessary.

Machine rates are a common means of calculating the cost of operating forest machines. A critical component machine rate calculations is that of repair and maintenance. Contractor records were collected from Maine, Vermont, and New Hampshire to compare current to published repair and maintenance rate originally developed in the early 1980’s. Comparison of these rates showed that current expenditure on repair and maintenance are significantly lower than estimates provided by previous publications. Established methods of calculating machine rates may need to be restructured, and at the very least estimates of calculating machine rates should be revisited.

The comminution of forest biomass for transport to end-use facilities is of critical importance. This responsibility is most often that of in-woods chippers. The production of these machines is of great importance to the proper configurations of machines to meet specific needs of companies that operate them. Time in motion studies were carried out on five different chippers operated by five different companies across the state of Maine. Productivity during productive machine hours was similar for all of the machines studied. Delays of these operations were also analyzed. Organizational delays were the single largest reason for inactivity of chippers and the crews that operate them. Trucking was the single largest cause of organizational delays, reducing delays from trucking would help improve productivity of chippers during scheduled machine hours.

Quality of chips produced by in-woods chippers is of importance to consumers of this forest product. Physical and chemical properties of these wood chips affect the transport, storage, internal transport, combustion, and emissions within these end-use facilities. Chip-size distribution, moisture content, specific gravity, ash content, higher heating value (energy content), and chlorides were tested for chips sampled during productivity studies. All chips sampled were within expectations of woodchip fuel specifications in the Northeastern US.

Recommendations for future research in the aforementioned fields of study are to expand all sample sizes, and create more uniform systems of record keeping for machine repair and maintenance records. Result from this study provide a cursory look at biomass supply chains and some of the expenses and challenges that they must overcome. Better understanding the actual costs faced by producers of forest biomass will only help strengthen this emerging industry.