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 explained 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 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.