Abstract:

Woody biomass in the form of forest residues is a potential source of sustainable renewable energy. However, the amount of these residues recovered from timber harvesting sites is far less than what is actually generated. This study focuses on estimating the amount of forest residues recovered from whole-tree harvesting sites using ground-based shovel logged and cable yarded harvesting systems in northern California. Inventories of standing trees along with pre- and post-harvest downed woody debris (DWD) surveys were used to estimate the total amount of aboveground biomass (AGB) in the study sites. Localized allometric biomass equations were used to estimate the pre-harvest AGB in standing trees. The amount of sawlogs and hog fuel recovered from the harvesting sites was collected from scale tickets. Forest residues delivered compared to the estimated amounts of forest residues generated were 70 percent for the shovel logged unit and 60 percent for the cable yarded unit. The amount of pre- vs. post-harvest DWD estimated from the inventory analysis for the cable and shovel units was increased by 42 and 23 percent, respectively. The methodology used for this study could be applied in other research focusing on determining a more accurate estimate of biomass recoverable from various harvesting systems.

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