Professor, Department of Forestry and Wildland Resources at Humboldt State University
Dr. Han’s primary research focuses on forest operations which involve the application of various forest management tools and processes to achieve a wide range of objectives in forest management. He has been evaluating various harvesting equipment and systems that are commonly used in timber harvesting and biomass operations. Especially, development of innovative operations logistics for forest biomass harvesting, processing and transportation for energy generation has been a main theme of my research for the last 15 years. His current research interest is to develop efficient biomass supply chain logistics that are specially designed for enhancing economic and technical feasibility of forest residues and small-diameter trees. Collaboration with other disciplines such as wood chemistry (e.g. torrefaction) and forest ecology (nutrient recycling with torrefied wood chips) has been also a key approach to comprehensively address recent challenges related to harvesting and utilization of dead trees and fuel reduction thinning materials. Recently, Dr. Han, along with 13 Co-PIs (Principal Investigators) and research partners, has received a $5.88 million grant from the U.S. Department of Energy to conduct biomass research on the utilization of forest residues for production of bioenergy and biobased products. The research collaboration effort integrates three major tasks of 1) production of quality feedstock, 2) development of mobile biomass conversion technologies, and 3) economic/environmental analysis, as explained in the research project web site at www.wastetowisdom.com.
Biomass Utilization, Harvesting, and Markets
Emerging biomass conversion technologies, such as mobile biochar or pyrolysis/torrefaction machines, aim to use forest residues left after extracting merchantable timber or fuel reduction thinning operations. The residues generated from these operations typically produce low quality feedstock which may not be suitable for new biomass conversion technologies. In an effort to increase feedstock quality, we separated sub-merchantable trees and tops and processed them to create stem wood piles during the timber harvest. Sorting and processing the forest residues can facilitate the production of quality feedstocks by chipping processed stem woods, instead of grinding a mix of tops, limbs and branches. The quality of the feedstock produced from the sorted materials was characterized by moisture content, particle-size distribution, bulk density, and ash content.
Our study results showed that a high quality feedstock can be produced by separating stem wood from other residues during a timber harvest. The cost of sorting biomass trees and tree-tops slightly increased the overall cost of the timber harvest operation, compared to the typical practice of piling the forest residues altogether. However, this additional sorting and processing practice of tree tops effectively facilitates increased utilization of forest residues to high value markets such as post & poles and dowels and thereby enhancing the financial potentials as well as avoiding open burning and facilitating tree replanting tasks.
This presentation also explains the testing results on four different methods (teepees, criss-cross, processor piled, and scattered) used to reduce moisture content in forest residue materials left on a timber harvest site. The information to be presented at this workshop is based upon the Waste to Wisdom (http://wastetowisdom.com/) research work supported by a grant from the U.S. Department of Energy under the Biomass Research and Development Initiative (BRDI) program.