Forest Project Protocol Resources

Biomass Equations

The biomass equations have been obtained from the United States Forest Service Forest Inventory and Analysis (FIA) National Program. The equations are the same equations used to generate the Common Practice estimate for each Assessment Area (by site class where applicable). Project Developers must use these same equations for their projects.

The form of the equations varies by region. The equations for the Western Coastal United States (Oregon, Washington, and California) incorporate regional equations (Region I) to estimate biomass in the various portions of the above-ground portion of the tree, including the stump, the bole, the top branches and leaves. The equations for the remainder of the United States (outside of coastal Alaska and Hawaii, where no FIA data exists or has not been analyzed to date for Reserve purposes) utilize FIA regional cubic volume equations and incorporate the Forest Service’s Component Ratio Method to estimate the volume in the non-bole portions of the tree. Please note that Improved Forest Management projects are not eligible in Alaska and Hawaii at this time.

Implementing the Component Ratio Method consists of first calculating gross cubic foot volume of each tree, living and dead. Gross cubic foot volume must then be converted to sound cubic foot volume by subtracting rotten and missing cull volume. Biomass is then calculated for individual tree components for each tree using the Component Ratio Method, with DBH and sound cubic foot volume as inputs.

Steps for Projects outside of California, Oregon, Washington, Alaska, and Hawaii

  • Step 1. Identify the Supersection your project is located in from the GIS Supersection Shape File located below.
  • Step 2. Identify the volume equation to use for each species in your project by Supersection in the attachment identified as: Volume Equation References and Coefficients by Species for Supersections outside of California, Oregon, Washington, Alaska, and Hawaii. The coefficients for the equations are provided in the same document.
  • Step 3. Calculate gross cubic foot volume for each tree, using the equations provided, from a 1 foot stump to a 4 inch top. This will yield the value for VOLCFGRS which must then be converted to VOLCFSND (sound cubic foot volume) by subtracting rotten and missing cull volume in the central stem of each tree.
  • Step 4. Download “Biomass Estimation using the Component Ratio Method” (located below) and follow the instructions to calculate biomass for each tree using VOLCFSND from Step 3 and DBH. This FIA document is Appendix J, “Biomass Estimation in the FIADB” of The Forest Inventory and Analysis Database: Database Description and Users Manual Version 4.0 for Phase 2.

Steps for Projects in California, Oregon, and Washington

  • Step 1. Identify the Supersection your project is located in from the GIS Supersection Shape File located below.
  • Step 2. Use the appropriate volume equation identified in the Volumetric Equations for California, Oregon, and Washington.
  • Step 3. Use the appropriate biomass equation identified in the Biomass Equations for California, Oregon, and Washington.

References

Assessment Area Data

The Assessment Area Data File contains common practice carbon stock estimates for the Forest Inventory and Analysis (FIA) Assessment Areas areas across the United States, mill efficiency data for harvested wood products and FIA supersection maps of the U.S. forest regions. These documents are available independent of the protocol and can be downloaded below.

Supplementary Documents

Note on Appendix F and the FIA Data Tables

Projects should use the most recent version of the Assessment Area Data File available on this website. Please note that the FIA statistic is based on the above-ground portion of the tree and is stratified into high and low site classes where it was possible to do so. Guidance for use of the Assessment Area Data File is contained in Appendix F of the Forest Project Protocol.

Please contact Policy Team with questions or comments.

Forest Project Forms

NOTE: The Forest Project Calculation Worksheet has been updated as of February 2, 2012. The following is a list of changes made to the worksheet:

  • Cell B35, the description header has been changed to clarify the comparative calculation taking place (trees harvested for wood products rather than harvested wood products)
  • Accounting for harvested trees and wood products has been removed from the calculation sheet for the Start Date entry. The Start Date entry is one point in time and compares stocks present at that particular point in time. Since time is needed to harvest trees and create wood products, the entries for harvested trees and wood products will commence on the calculation worksheet in the subsequent entry. Users should be aware that the inclusion of harvested wood products in the subsequent entry may result in a reversal if harvest in the baseline exceeds harvest and growth in the project.