1.3. Navigating the Report We studied the progression of biomass that begins with a forest operation and finishes at a facility’s gate. We followed this progression noting whether forest biomass remained on site or was removed and used to support economic activity. Figure 2 outlines the progression of biomass that began with a harvest operation, producing post-timber harvest biomass and culminated as market biomass. Residual biomass production occurred at each step of the process. In addition to the residual biomass produced as a byproduct of a forest operation, there existed a range of woody material prior to the forest operation. Table 1 found at the end of the section provides definitions for biomass terms used.
Pre-existing woody material
Post-timber Harvest Biomass
Residual Harvested Biomass Residual Potential Market Biomass
Forest Operation
Harvested Biomass
Potential Market Biomass
Merchantable Stem Volume
Residual Market Biomass
Market Biomass
Figure 2. Flow of biomass produced as a byproduct of a forest operation from forest to market
Post-timber harvest biomass was determined using inventory plot data for Washington state, growth and yield models that used the plot data, forest operation behavior and biomass equations, all contained in a newly-developed biomass database. The details of the study methods, models and the database are described in Part 2 of the report. Post-timber harvest biomass was produced as a byproduct of a forest operation, and was either piled and brought to a roadside (harvested biomass), or remained scattered on site (residual harvested biomass). Equipment configuration and type determined whether post-timber harvest biomass reached the roadside. The study team used field surveys to collect information on the range of harvest configurations that determined whether post-timber harvest biomass became harvested biomass or residual harvested biomass.
Washington Forest Biomass Assessment Report 2012/03/13
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