This page last reviewed December 2, 2015

Compliance Offset Protocol U.S. Forest Offset Projects

Adopted June 25, 2015

This page describes the ARB Compliance Offset Protocol for U.S. Forest Projects adopted June 25, 2015 (2015 Forest Protocol) and all supporting documents for project implementation. The calculations for estimating volume and converting biomass to CO2e vary by project location.  Forest projects may be located in the United States including regions of Alaska. Hawaii, and U.S. territories are not eligible at this time. Offset Project Operators or Authorized Project Designees (OPOs/APDs) listing projects located in Alaska, California, Oregon, and Washington may refer to Table 1. OPOs/APDs listing projects within the other 45 contiguous states may refer to Table 2.  

OPOs/APDs that have listed projects under the October 20, 2011 Compliance Offset Protocol for U.S. Forest Projects may refer to that version's U.S. Forest Offset Projects webpage. 

OPOs/APDs that have listed under the November 14, 2014 Compliance Offset Protocol for U.S. Forest Projects may refer to that version's U.S. Forest Offset Projects webpage.

Skip to: Approved Growth and Yield Models

Skip to: Guidance in the form of Frequently Asked Questions

Skip to: Guidance for U.S. Forest Projects Transitioning from Early Action to Compliance 

Skip to: Compliance Offset Program Forms to obtain forest offset project listing forms and forest Offset Project Data Report forms

Introduction

For projects listed on or after November 1, 2015, an OPO/APD must use the 2015 Forest Protocol to quantify and report GHG reductions and GHG removal enhancements.

The Forest Protocol provides requirements and methods for quantifying the net climate benefits of activities that sequester carbon on forestland. The protocol provides offset project eligibility rules; methods to calculate an offset project’s net effects on greenhouse gas (GHG) emissions and removals of CO2 from the atmosphere (removals); procedures for assessing the risk that carbon sequestered by a project may be reversed (i.e. released back to the atmosphere); and approaches for long-term project monitoring and reporting. The protocol is designed to ensure that the net GHG reductions and GHG removal enhancements caused by an offset project are accounted for in a complete, consistent, transparent, accurate, and conservative manner and may therefore be reported as the basis for issuing ARB or registry offset credits.

The protocol provides eligibility rules, methods to quantify GHG reductions, project-monitoring instructions, and procedures for reporting Offset Project Data Reports. Additionally, all offset projects must submit to independent verification by ARB-accredited verification bodies. Requirements for verification bodies to verify Offset Project Data Reports are provided in the Cap-and-Trade Regulation. 

ARB Video: "California's forest offset protocol" (CAFR5011--Yurok project)

ARB Video: "Forest offset project benefits tribes and state" (CAFR5028--Round Valley project)

U.S. Forest Protocol Resources

Compliance Offset Protocol U.S. Forest Projects (June 25, 2015)pdf (PDF - 1.15MB)

Table 1: Documents for Projects Located in Alaska, California, Oregon, and Washington

Description

Instructions





The Forest Protocol requires estimates of total above-ground and below-ground biomass. OPOs/APDs with projects located in Alaska, California, Oregon, and Washington should use these instructions to convert biomass to tons of CO2e emissions or revomal enhancements.
Supersection Maps:

        Lower 48 States
        Projection: Albers

        Alaska
.        Projection:AK Albers
Supersection MapStep 1:  Supersection maps identify the appropriate Supersection and Assessment Area corresponding to the project’s location.  An OPO/APD must first determine the geographic Supersection within which the Project Area is located by reviewing the Supersection maps.  A GIS shapefile of the Supersection may be downloaded to map the project boundaries for reporting purposes.  
Assessment areas for the lower 45 states are not geographically defined therefore shapefiles are not available. Assessment areas are determined by species composition, tember markets, and topography/watersheds.


Projects in Alaska are eligible if they are located within the approved supersection for Southeast and Southcentral Alaska. Alaska assessment areas are geographically defined. Shapefiles are provided for each assessment area.
Assessment Area Data File


Step 2:  After the OPO/APD identifies the correct Supersection for its Project Area, the OPO/APD must consult the Assessment Area Data File to identify the Assessment Area that best corresponds to the project, based on the dominant vegetation present in the "forest type" category within the spreadsheet.  The Assessment Area Data File provides information that must be used as inputs to meet Protocol requirements.  Click here for more details on the categories contained in the Assessment Area Data File.
Volume and Biomass Equations - Projects located in Alaska, California, Oregon, and Washington             

note: The AK equations do not require use of a separate volume equation for estimating biomass.

note: 
Project operators listing projects located in AK, CA, OR, WA must not use the volume equations or coefficients found in Woodall et al. (2011)
Step 3:  For projects located in CA, OR, and WA:
The OPO/APD must first estimate volume by species using the volume models and associated coefficients found within the document "Volume Equations for projects located in CA, OR, WA (9/19/14)". The OPO/APD then estimates total biomass in the forest once volume is determined using the biomass equations provided in "Regional Biomass Equations for Projects Located in CA, OR, WA (9/19/14).  All volume models and biomass equations for CA, OR, and WA are regional equations provided by the Forest Inventory and Analysis (FIA) Program of the United States Forest Service. The CA, OR, WA volume models found in Woodall et al (2011) must not be used for estimating carbon for these states. .      

For projects located in AK:
The OPO/APD estimates biomass directly using the document  "Alaska Biomass equation (November 5, 2002)"  These are regional biomass equations provided by the FIA. The AK volume models found in Woodall et al (2011) must not be used for estimating carbon for AK projects.   
Estimating Carbon in Wood Products
















Step 4:  For projects that include harvesting, the OPO/APD must estimate the carbon stored in harvested wood products. Follow Appendix C to estimate carbon in harvested wood products for both the baseline and actual project scenario.  OPO/APDs will need each document listed dependign on project location.

Step 4a: Specific Gravity and Wood Density Factors:
The volume or weight of carbon in trees harvested (prior to delivery to a mill) is estimated from model output treelists. The merchantable portion is calculated from modeling outputs (baseline scenario) or verified mill reports (project scenario).  If harvested wood is measured in volume, the specific gravity and wood density factors by forest type are applied to harvested wood volumes to calculate carbon weight.These factors are found in Smith et al (2006) for projects located in Alaska, California, Oregon and Washington. If harvested wood is measured in weight, the water weight must be subtracted in order to find the carbon weight.   

Step 4b: Regional Mill Efficiency Data
Apply the default mill efficiencies within the Regional Mill Efficiency Data worksheet for the appropriate region to calculate the harvested carbon that is transferred into a harvested wood product.
 
Step 4c: Wood Product Classes
Determine the percentage of each wood product class produced during the reporting period. This is done by obtaining either the default wood product classes assigned to each supersection in the Wood Products Generated worksheet within the Assessment Area Data File or by obtaining a verified scaling report from the mill(s) where the project's logs are sold indicating the product categories the mill(s) sold for the reporting period in question. Multiply the harvested carbon that is transferred into a product by the percentage within each product class to get the carbon in each product class.
 
Step 4d: Storage Factors
Determine the average carbon that would remain stored in “in-use wood products” and in “wood products in landfills” over 100 years using the weight of carbon in each product class and the 100-year average storage factors provided in Appendix C of the protocol. Sum all of the wood product classes to get the total long-term carbon storage in “in-use wood products” and “wood products in landfills”. In years when actual harvest volume (prior to delivery to a mill) exceeds estimated baseline harvest volume (prior to delivery to a mill) assessed cumulatively since the project start of the first reporting period, landfill carbon storage is excluded from the wood product calculation.



Table 2: Documents for Projects Located Within the Other 45 Contiguous States (Outside Alaska, California, Oregon, and Washington)

Description

Instructions





The Forest Protocol requires estimates of total above-ground and below-ground biomass. OPOs/APDs with projects located in all approved states except Alaska, California, Oregon, and Washington (lower 45 states) should use these instructions to estimate volume and convert biomass to tons of CO2e emissions or removal enhancements.  The Protocol requires use of specific volume equations found in "Methods and Equations for Estimating Aboveground Volume, Biomass, and Carbon for Trees in the U.S. Forest Inventory, 2010" . Coefficients are found in the regional Coefficients Database associated with the Woodall document. OPOs/APDs must estimate biomass using the Component Ratio Method (CRM); the CRM is applicable to all states except California, Oregon, and Washington. 
Supersection Maps

Supersection MapStep 1:  An OPO/APD must first determine the geographic Supersection within which the project area is located by reviewing the Supersection maps in this table.  Supersection maps identify the appropriate Supersection and Assessment Area corresponding to the project’s location.  A GIS shapefile of the Supersection may be downloaded to map the project boundaries for reporting purposes. 
Assessment Area Data File



Step 2:  After the OPO/APD identifies the correct Supersection for its Project Area, the OPO/APD must consult the Assessment Area Data File to identify the Assessment Area that best corresponds to the project, based on the dominant vegetation present in the ‘forest type’ category within the document.  The Assessment Area Data File provides information that must be used as inputs to meet Protocol requirements.  Click here for more details on the categories contained in the Assessment Area Data File.
Volume Estimation and Biomass Equations - Projects Located Outside of California, Oregon, and Washington




















Step 3a: The "Methods and Equations for Estimating Aboveground Volume, Biomass, and Carbon for Trees in the U.S. Forest Inventory, 2010" document provides cubic foot gross and sound volume models for the 45 states by region and species1.  The OPO/APD will need the accompanying “Coefficients Database” to determine the correct coefficients to use for gross and/or sound volume. 

Step 3b: Use the Coefficients Database to find the appropriate coefficients by project location and species.  Coefficients for the same species may be different in two different locations.  Gross cubic foot volume (VOLCFGRS) must be converted to sound cubic foot volume (VOLCFSND) by subtracting rotten and missing cull volume.

Step 3c:
The standing dead tree carbon pool must be adjusted for density reduction and structural loss using the approach established in "Accounting for density reduction and structural loss in standing dead trees: Implications for forest biomass and carbon stock estimates in the United States." General guidance for using the Domke method is found here.

Decay class, density reductions factors (DRFs), and structural loss adjustment (SLA) factors are necessary to complete calculations for standing dead trees.  Decay class and DRFs are found in Appendix B of "Differences Between Standing and Downed Dead Tree Wood Density Reduction Factors: A Comparison Across Decay Classes and Tree Species" under the column labeled "SD."  Where species are not found or missing DRFs (in Appendix B), OPOs/APDs must identify a value by appropriate decay class from within the same genus (from Appendix D). If this is not possible, use the hardwood/softwood default values found in Table 6 of Harmon (2011).  OPOs/APDs should always cite the source of the DRF and column within the source for ease of verification.

SLA factors can be found in Table 2 of Domke (2011) for decay classes 1-5 for top, bark, bole, stump and roots.  These SLA factors are applicable to all species.

Biomass is then calculated for individual tree components following the Component Ratio Method.

Step 3d: The "Biomass Estimation Component Ratio Method" document is an excerpt from the FIA Database User’s Manual2 and should be used to calculate biomass for all projects outside California, Oregon, and Washington.  It provides a nationally consistent method of estimating tree biomass, called the Component Ratio Method (CRM)3.  The CRM involves calculating the dry weight of individual components before estimating the total above-ground or below-ground biomass.  The tables in this document describe the equations used to estimate various components of tree biomass (stem wood, top and branches, bark, stump, course roots).  Most components are estimated through a series of ratio equations4

The “Biomass Coefficients for Use with the Component Ratio Method” document must be used in conjunction with the document in Step 3a.  It provides the coefficients for common species that are necessary to estimate biomass using the Component Ratio Method..
Estimating Carbon in Wood Products
















Step 4:  For projects that include harvesting, the OPO/APD must estimate the carbon stored in harvested wood products. Follow Appendix C to estimate carbon in harvested wood products for both the baseline and actual project scenario.  OPO/APDs will need each document listed dependign on project location.

Step 4a: Specific Gravity and Wood Density Factors:
The volume or weight of carbon in trees harvested (prior to delivery to a mill) isestimatedfrom model output treelists. The merchantable portion is calculated from modeling outputs (baseline scenario) or verified mill reports (project scenario).  If harvested wood is measured in volume, the specific gravity and wood density factors by forest type are applied to harvested wood volumes to calculate the biomass weight. These factors are found in the USFS Wood Handbook for projects located in all states except AK, CA, OR, and WA. If harvested wood is measured in weight, the water weight must be subtracted in order to find the carbon weight. 

Step 4b: Regional Mill Efficiency Data
Apply the default mill efficiencies within the Regional Mill Efficiency Data worksheet for the appropriate region to calculate the amount of harvested carbon that is transferred into a harvested wood product.
 
Step 4c: Wood Product Classes
Determine the percentage of each wood product class produced during the reporting period,.  This is done by obtaining either the default wood product classes assigned to each supersection in the Wood Products Generated worksheet within the Assessment Area Data File or by obtaining a verified scaling report from the mill(s) where the project's logs are sold indicating the product categories the mill(s) sold for the reporting period in question.   Multiply the harvested carbon that is transferred into a product by the percentage within each product class to get the carbon in each product class.
 
Step 4d: Storage Factors
Determine the average carbon that would remain stored in “in-use wood products” and in “wood products in landfills” over 100 years using the weight of carbon in each product class and the 100-year average storage factors provided in Appendix C of the protocol. Sum all of the wood product classes to get the total long-term carbon storage in “in-use wood products” and “wood products in landfills”. In years when actual harvest volume (prior to delivery to a mill) exceeds estimated baseline harvest volume (prior to delivery to a mill) assessed cumulatively since the project start of the first reporting period, landfill carbon storage is excluded from the wood product calculations. In years when actual harvest volume (prior to delivery to a mill) is less than estimated baseline harvest volume (prior to delivery to a mill), landfill carbon storage is included in the wood product calculation. 
Footnotes
[1] Cubic foot volume calculations are necessary for trees with diameters greater than or equal to 5 inches.  Trees with diameters less than 5 inches do not require cubic foot volume calculations to estimate biomass using the Component Ratio Method.  Biomass for trees less than 5 inches in DBH is calculated with DBH only following Appendix J of the "Draft Forest Inventory Analysis Database Description and Users Manual, Version 4.0, Revision 2.
[2] Appendix J. December 2009. Draft Forest Inventory Analysis Database Description and Users Manual, Version 4.0, Revision 2.
[3] Heath et al. 2009.
[4] Jenkins et al. 2003.

References

Bailey, R. G.; Avers, P. E.; King, T.; McNab, W. H., eds. 1994. Ecoregions and subregions of the United States (map). Washington, DC: USDA Forest Service. 1:7,500,000. With supplementary table of map unit descriptions, compiled and edited by W. H. McNab and R. G. Bailey.

Forest Inventory and Analysis Database 6.0.  2009.  Appendix J.  In: DRAFT FIA Database Description and Users Manual for Phase 2, version 4.0, revision 2.  U.S. Department of Agriculture, Forest Service.

Harmon, Mark E.; Woodall, Christopher W.; Fasth, Becky; Sexton, Jay; Yatkov, Misha. 2011. Differences between standing and downed dead tree wood density reduction factors: A comparison across decay classes and tree species. Res. Pap. NRS-15. Newtown Square, PA: U.S. Department of Agriculture, Forest Service, Northern Research Station. 40 p.

Heath, Linda S.; Hansen, Mark; Smith, James E.; Miles, Patrick D.; Smith, Brad W.  2009.  Investigation into calculating tree biomass and carbon in the FIADB using a biomass expansion factor approach.  In: McWilliams, Will; Moisen, Gretchen; Czaplewski, Ray, comps. 2009. 2008 Forest Inventory and Analysis (FIA) Symposium; October 21-23, 2008; Park City, UT. Proc. RMRS-P-56CD. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station. 26 p.

Jenkins, Jennifer C.; Chojnacky, David C.; Heath, Linda S.; Birdsey, Richard A.  2003.  National scale biomass estimators for United States tree species.  Forest Science. 49: 12-35.

McNab, W.H.; Cleland, D.T.; Freeouf, J.A.; Keys, Jr., J.E.; Nowacki, G.J.; Carpenter, C.A., comps. 2007. Description of ecological subregions: sections of the conterminous United States [CD-ROM]. Gen. Tech. Report WO-76B. Washington, DC: U.S. Department of Agriculture, Forest Service. 80 p.

U.S. Department of Agriculture, Forest Service, Forest Inventory and Analysis National Core Field Guide (October 2010)

Woodall, Christopher W.; Heath, Linda S.; Domke, Grant M.; Nichols, Michael C.  2011.  Methods and equations for estimating aboveground volume, biomass, and carbon for trees in the U.S. forest inventory, 2010.  Gen. Tech. Rep. NRS-88. Newtown Square, PA: U.S. Department of Agriculture, Forest Service, Northern Research Station. 30 p.

Resource Materials for Projects in All Locations

Resources for Offset Project Operators

Resources for Verifiers

References for U.S. Forest Protocol




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For questions or comments regarding the U.S. Forest Protocol please contact

Barbara Bamberger at 916-324-2303 or e-mail bbamberg@arb.ca.gov.

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