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 Alaska, California, Hawaii, Oregon, and Washington incorporate regional equations 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 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. 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.
Projects in Alaska, California, Hawaii, Oregon, and Washington
||Batch 2.0 (projects listed June 28, 2017 or later)
Batch 1.1 (projects listed March 25, 2011 or later)
Batch 1.0 (optional for projects listed prior to March 25, 2011)
Projects in the Continuous Continental 45 States
||Batch 2.1 (projects listed October 16, 2019 or later)
Batch 2.0 (projects listed June 28, 2017 until October 15, 2019)
Batch 1.1 (projects listed prior to June 28, 2017)
Component Ratio Method Guidance
- Investigation into Calculating Tree Biomass and Carbon in the FIADB Using a Biomass Expansion Factor Approach Heath: An Article Describing the Component Ratio Method (March 26, 2010)
From: USDA Forest Service Proceedings – RMRS-P-56
- The Forest Inventory and Analysis Database: Database Description and Users Manual Version 4.0 for Phase 2 (March 26, 2010)
From: Forest Inventory and Analysis National Program
- U.S. Department of Agriculture, Forest Service, Forest Inventory and Analysis National Core Field Guide (October 2010)
- ARCHIVE: Combined Biomass and Volumetric Equations for California, Oregon, and Washington (OUTDATED May 13, 2009)