What is Wood Biomass

What is Wood Biomass?

Wood biomass is defined by RISI as any timber-derived product (softwood or hardwood) capable of being converted to energy through direct combustion or gasification; to solid fuel through pelletizing; or to liquid fuel through myriad processes.

While wood biomass may include any part of the tree, cost differentials in the various components is a primary limiting factor. Typically, biomass used in energy and fuel production comes from four primary sources:

  • Manufacturing residues
  • Non-merchantable timber harvest residuals
  • Post-consumer wood waste
  • Urban and agricultural wood waste.

Wood value is determined by local demand. Clear, straight, high-quality logs will usually find a market among veneer and lumber manufacturers at rates unattainable to the biomass industry. Likewise, pulp-grade logs may fetch returns too high among pulp mills or panel producers to be viable for biomass use. Absent higher-value end use, however, biomass available to market may creep into higher-grade material.

  • Manufacturing residues:Includes wood chips, shavings, sawdust, and bark left over from the production of lumber and structural panels. The cleaner the residual, the higher the value. Clean material usually diverts to the manufacture of pellets (or nonstructural panels), while dirtier material (also known as hog fuel) goes to the production of energy through combustion.
  • Timber harvest residuals:Typically include tops and limbs too small for lumber production or containing too much bark for pulp use. These are ground or chipped onsite and diverted to energy production. Trees of low value may also be chipped whole for use in energy production, or debarked and chipped for pellet manufacture.
  • Post-consumer wood waste: Generally includes lumber from construction scraps or demolition projects. Material from construction projects holds higher value, as it is usually cleaner, devoid of nails, and unlikely to be tainted with lead paint or other toxic materials.
  • Urban and agricultural wood waste: Includes (on the urban side) tree trimmings and storm debris. The agricultural side primarily includes orchard prunings.

Learn more about RISI's Wood Biomass contributors.