Methodologies

The Carbon Displacement Factor Tool enables users to evaluate the potential avoided emissions from using wood products instead of functionally equivalent alternative products and systems. The methods that underlie the Carbon Displacement Factor Tool are largely based on the quantification approaches published in the USDA Entity Guidelines Chapter 5: Methods for Managed Forest Systems (Murray et al., 2024) (herein after referred to as the “Entity Guidelines”) Section 5.2.2. Avoided Emissions or Emission Reductions from HWP Substitution and expanded upon in Droog et al (in review). The methods also are compatible with ISO 13391 Part 3 (ISO 2025).

CCF: Hundred cubic feet
CO₂e: Carbon dioxide equivalent
CORRIM: The Consortium for Research on Renewable Industrial Materials

DF: Displacement factor
EC: Embodied Carbon
EPD: Environmental Product Declaration
ISO: International Organization for Standardization 

IPCC: Intergovernmental Panel on Climate Change

ISO: International Organization for Standardization 

GWP: Global Warming Potential
HWP: Harvested Wood Product(s)
LCA: Life Cycle Assessment
Metric tonnes Unit of weight equal to 1,000 kilograms (2,204.6 pounds), or approximately 1.102 short tons (t) 

MBF: Thousand board feet
MDF: Medium Density Fiberboard
MSF:: Thousand square feet
m³: Cubic meters
MCF: Thousand cubic feet
NC: North Central (US Region)
NE: Northeast (US Region)

NLS: Northern Lake States (US Region)

PWE: Pacific Northwest, East side (US Region)

PWW: Pacific Northwest, West side (US Region)

PSW: Pacific Southwest (US Region)

RM: Rocky Mountain (US Region)

RMN: Rocky Mountain North (US Region)

RMS: Rocky Mountain South (US Region)

SC: South Central (US Region)

SE: Southeast (US Region)

U.S.: United States of America

USDA: United States Department of Agriculture

The Carbon Displacement Factor Tool provides displacement factors and estimates of substitution benefits that are limited to U.S. forests, products, and end-uses. The data used to compare wood end-uses with functionally equivalent alternatives are from U.S. and North America specific published comparative LCA studies and third-party verified EPDs.

3.1. Greenhouse Gas Sources and Sinks

The sources and sinks of greenhouse gasses (GHG) covered by the Carbon Displacement Factor Tool include the following:

• Biogenic Carbon Storage: The carbon stored in harvested logs or wood products.
• Fossil carbon emissions: The fossil emissions in cradle to gate life cycle assessments.

3.2. System Boundary

The global warming potential (GWP) values in the Carbon Displacement Factor Tool are cradle-to-gate (see Figure 1), meaning they cover emissions up until the factory gate.  Thus they do not by themselves represent use, end-of-life, landfill storage or later emissions. 

Specifically, the GWP values are based on the A1–A3 “product-stage” life-cycle modules as defined in ISO 21930, which include the following: 

• A1 – Raw material supply and Upstream Processes: Covers extraction and processing of raw materials, and the supply of any secondary materials used as inputs. For a wood product, this would include forest resource extraction/harvest inputs and the sourcing of any other raw materials (resins, additives, etc.).
• A2 – Transport: Transport of those raw materials from the point of extraction/supply to the manufacturing gate. Includes fuel use and emissions from that logistics leg.
• A3 – Manufacturing: The actual production process converting raw materials into the finished product. Includes energy and material inputs at the manufacturing facility, on-site waste processing, and production of any ancillary materials/packaging.

Figure 1: Generic Presentation of Life Cycle Stages of HWPs in LCA Studies. Source: USDA Entity Guidelines, Quantifying greenhouse gas fluxes in agriculture and forestry: Methods for entity-scale inventory, Technical Bulletin 1939, 2nd ed., Chapter 5 (2024) (Section 5-B.2.3 LCA Method Overview and Demonstration) 

3.3. Caveats and Context for Users

The Displacement Factor Tool was developed to provide users with broad, first-order estimates of displacement factor and potential substitution benefits. Users should understand that the results are intended to provide estimates of potential magnitude of the greenhouse gas impacts of using more or less wood. 

This tool cannot be used to make official claims on the extent of substitution and the associated climate mitigation that will actually be realized. Market dynamics, shifting consumption patterns, design specifications, and data availability all influence actual potential substitution in ways not captured by this methodology. Results should be treated as a modeled estimate rather than a verified impact. See ISO 13391 (2025) for more information about context for users.

Furthermore, the substitution benefits apply only to decisions that change how much wood is produced or used, for example, choosing wood over a non-wood alternative for a new build, or increasing/decreasing wood harvest levels. It does not apply to wood that is already being used or produced, since no non-wood material is actually being avoided in that case. The emissions "savings" only materialize when the choice genuinely shifts material demand. 

3.4. Sources of Uncertainty

Uncertainty in the Carbon Displacement Factor Tool’s outputs primarily arise from limitations in the underlying data. Specifically, these limitations include: 

• Data Completeness:  the underlying database contains only the wood end-uses and alternatives with which there is published credible and comparable data. This database will be continuously updated to better represent the full spectrum of wood end-uses and potential non-wood alternatives. Users are encouraged to reach out via the FACT contact form if they have published LCA information that could be included in the database. 
• Age of Data: The default log-to product allocations are from Smith et al (2006) Table D6. The default product to end-use allocations are adapted from Mckeever et al 2009 and 2011. These datasets may not reflect the current product and end-use fiber flows.  Efforts are underway to update both of these parameters to reflect more contemporary use trajectories of wood products, which will be incorporated in future versions of the Tool.

The Carbon Displacement Factor Tool provides users three entry pathways depending on the desired output. These are summarized below:

• End use: Describes different wood product end-uses and their alternatives
• Product: Provides a weighted displacement factor for typical U.S. wood products based on their end-uses.  
• Forest: Provides a weighted displacement factor for a harvested log based on their typical product mix for their region and log type. 

The following describes these options in detail as well as required user inputs 

4.1 End-use

This analysis pathway enables users to select an end-use to compare alternative products or systems. Required inputs are described below and the full range of input options is presented in Table 1. 

End use: The end use describes the final application in which a wood product is used.  The Carbon Displacement Factor Tool includes five broad wood product end-use categories: construction- buildings, construction- repairs, furniture, energy, packaging.  

End use sub-category: For each end-use category, a user can select from an array of sub-categories, which represent current data in the data-base. These subcategories may be expanded as more data becomes available

Reference material: This represents the wood material against which all other non-wood materials are compared. The properties of this reference material, such as its GHG emissions, carbon storage, and lifespan, are then used as inputs for the displacement factor calculation. The Reference Material is selected through a drop-down menu and only includes relevant wood material for the selected end-use subcategory.

Material Quantity: This is a number that corresponds to the unit associated with the reference material (e.g. m³). This number is used to calculate the substitution benefit.

Alternative Materials: This drop-down menu shows the different alternate material types functionally equivalent to the reference material, for which published data exist that meet the data quality requirements outlined in Droog et al. (in review) Most combinations offer multiple alternate material type options to compare or users may select “all” to compare them all. 

4.2 Product

This analysis pathway enables users to select a specific product to estimate the avoided emissions associated with its use. Users may either enter the product information directly into the user interface or upload a completed template. The following information is required:

Product: Users may select from eleven commodity wood products (see Table 2) adapted from USFS GTR 289 (Alderman 2022). The displacement factor and substitution benefits are calculated as a weighted average of the different end-uses that the selected product goes into in the United States.

Quantity: A user enters a quantity in the units that correspond to the selected product default unit (also presented in Table 2 below). The products and units are based on the USDA Forest Service  standard units for reporting U.S. wood products.

4.3 Forest (Harvested Log)

This analysis pathway enables users to estimate the potential downstream avoided emissions associated with a harvest. Users may either enter the product information directly into the user interface or upload a completed template. This analysis pathway requires users to select which region the harvested log was sourced from, the log type, enter the harvest quantity, and select a fiber flow, as described below.

Region: Users select from one of eight regions: 

1. North Central
2. Northeast
3. Pacific Northwest West
4. Pacific Northwest East
5. Pacific Southwest
6. Rocky Mountain
7. South Central
8. Southeast

These regions are based on Smith et al. (2006) regional delineations presented in Figure 1 within that publication, but modified to match those presented in Smith et al. (2006) Table D6. Specifically, the Northern Lake States (NLS) and Northern Prairie States (NPS) are combined to form NC (North Central) and the Rocky Mountain North (RMN) and Rocky Mountain South (RMS) are combined to form a single Rocky Mountain region (RM).  Figure 2 shows the adapted regional delineation applied in the Carbon Displacement Factor Tool. 

Figure 2: Roundwood allocation regions. Adapted from Smith et al. (2006) to reflect data resolution in Smith et al. (2006) Table D6. Pacific Northwest, West (PNW);  Pacific Northwest, East (PWE); Pacific Southwest (PSW); Rocky Mountain (RM); North Central (NC); South Central (SC); Northeast (NE); Southeast (SE). 

Log Type: Users can enter harvest amounts separately for softwood and hardwood. Where users know the log type (i.e., sawlog or pulpwood), they may differentiate them using the “separate sawlog/pulpwood” toggle.  

Harvest Quantity: A user enters the volume of harvested log that leaves the site (e.g. is delivered to a mill) corresponding to the log type selected. The user can choose between the following common log units: BF, MBF, CF, CCF, m³, short ton, metric ton.

Fiber Flow: The default values are based on Smith et al (2006) Table D6. A user can override these values with more granular data as long as they still sum to 100%. For example, California, Washington, and Oregon specific fiber flows can be found in the CALFire HWP Carbon Model, HWP Data Visualization under “existing data”: https://github.com/jeremygroom/HWP-C-vR/tree/main/HWP%20Data/ExistingData

After the Carbon Displacement Factor Tool processes the user-supplied information, summary metrics and graphical outputs are presented in the user interface. Those corresponding to each of the three analysis pathways the Carbon Displacement Factor Tool includes are presented below.  

5.1 End-use 

Summary metrics:

• Materials by Displacement Factor: A displacement factor (DF) measures the GHG emissions avoided when wood is used instead of nonwood fossil or petroleum-based material (kg CO₂/kg CO₂) . DFs are estimated by comparing the total GHG emission differences between wood and nonwood products and divided by the corresponding carbon content (expressed as CO2e). The equation, from Sathre and O’Connor (2010) is used in the the USDA Entity Guidelines Chapter 5: Methods for Managed Forest Systems (Murray et al. 2024)  as well as ISO 13391. This lists the DFs of all the materials that are compared to the reference material.
• Average Displacement Factor: Average Displacement Factor represents the average displacement of all the non-wood alternatives to the wood reference material (kg CO₂/kg CO₂). If there is only one alternative this number will be the same as displacement factor.
• Average Potential Substitution: Average potential substitution indicates how much GHG emissions could potentially be saved by using wood instead (kg CO₂e). This value is calculated using the quantity of reference material the user inputs and the average displacement factor of the alternative materials and will scale as the material quantity changes. 

Note: the substitution benefits apply only to decisions that change how much wood is produced or used, for example, choosing wood over a non-wood alternative for a new build, or increasing/decreasing wood harvest levels. It does not apply to wood that is already being used or produced, since no non-wood material is actually being avoided in that case. The emissions "savings" only materialize when the choice genuinely shifts material demand. 

Graphical outputs: 

• Global warming potential lifespan and biomass scatter plot (Figure 3): Displays the reference and alternative materials by lifespan (yrs) (x-axis), GWP (kg CO₂e/unit material) (y-axis) and biomass (dotted circle). Each material displays the actual numbers.  
• Displacement Factor for alternative material types compared to reference material table (Figure 4): Lists the reference material and alternative materials by the following columns:
• • Material: name of the inputted material
  • Type:  the component of the material, e.g., Wood, plastic, steel, composite
  • Lifespan (years): The service life of the material. This value does not change with material quantity. Note: the lifespan of pallets is in trips not years.
  • GWP (kg CO₂ equivalent): The embodied carbon associated with manufacturing and transportation of the material. This value increases proportionally with the quantity of the material.
  • Kg Wood biomass (kg): The amount of biomass stored in the wood-materials (in kg). This value is constant.
  • Displacement Factor (kg CO₂e/kg CO₂): the total GHG emission differences between the alternative product and the reference material divided by the corresponding carbon content differences (expressed as CO₂e).
  • Source: The citation (e.g., published life cycle assessment) from where the GWP, wood carbon, and lifespan information is derived.

Figure 3: Graph showing Global Warming potential by lifespan and biomass

Figure 4: Table showing displacement factor for alternative material types compared to reference material

5.2 Product 

Summary metrics:

• Total Average Displacement Factor: The average displacement factor of all the inputted products (unitless) (see Eq DF-7). 
• Total Estimated Potential Substitution:  Indicates how much GHG emissions could potentially be saved by using wood instead  (kg CO₂e). This value is calculated using the quantity of products the user inputs and will scale as the material quantity changes (See Eq DF-8). 

Note: the substitution benefits apply only to decisions that change how much wood is produced or used, for example, choosing wood over a non-wood alternative for a new build, or increasing/decreasing wood harvest levels. It does not apply to wood that is already being used or produced, since no non-wood material is actually being avoided in that case. The emissions "savings" only materialize when the choice genuinely shifts material demand. 

Graphical outputs:

• Total potential estimated substitution/displacement factor by product bar chart (Figure 5): Displays the total displacement factor (Eq DF-5) and estimated potential substitution (Eq DF-6) by product.  The bar chart also displays the confidence intervals associated with each estimate, assuming:
• • Upper Limit (unitless): The 90% confidence interval above the DF
  • Lower Limit (unitless): The 90% confidence interval below the DF
• Potential displacement factor (DF) and substitution per product table (Figure 6):  Lists information about the inputted products in the following columns:
• • Product: Each inputted product
  • Quantity: The quantity of material the user input for each inputted product (expressed in the default unit associated with the product).
  • Estimated Potential Substitution (kg CO₂e): indicates how much GHG emissions could potentially be saved from the inputted quantity of product. See Eq-DF-6. This value will scale as the product quantity changes.
  • Displacement Factor (unitless): The weighted average of all the average end-use DFs in which the product is used. See Eq DF-5.

Figure 5: Graph showing total potential estimated substitution and displacement factor by product

Figure 6: Table showing potential displacement factor and substitution per product

5.3 Forest (Harvested Logs) 

Summary metrics:

• Total Average Displacement Factor: The average displacement factor of all the inputted harvested logs (unitless). 
• Total Estimated Potential Substitution:  Indicates how much GHG emissions could potentially be saved by using wood instead (kg CO₂e). This value is calculated using the quantity of logs the user inputs and will scale as the material quantity changes. Note: the substitution benefits apply only to decisions that change how much wood is produced or used, for example, choosing wood over a non-wood alternative for a new build, or increasing/decreasing wood harvest levels. It does not apply to wood that is already being used or produced, since no non-wood material is actually being avoided in that case. The emissions "savings" only materialize when the choice genuinely shifts material demand. 

Graphical outputs:

• Total potential [estimated substitution] and [displacement factor] by region bar chart (Figure 7): Displays the total displacement factor (Eq DF-9) and estimated potential substitution (Eq DF-10) by region. The bar chart also displays the confidence intervals associated with each estimate, assuming:
• • Upper Limit (unitless): The 90% confidence interval above the DF
  • Lower Limit (unitless): The 90% confidence interval below the DF
• Potential displacement factor (DF) and substitution by region table (Figure 8): Lists information about the inputted products in the following columns:
• • Category: The log types selected from the user in the input menu (e.g., softwood (sawlog))
  • Region: The region that corresponds to the inputted log type
  • Quantity: The quantity of material the user input for each inputted product (expressed in the unit selected for each product)
  • Estimated Substitution (kg CO₂e): indicates how much GHG emissions could potentially be saved from the amount of harvested log. This value will scale as the product amount quantity changes. See equation DF-10
  • Displacement Factor (unitless): The weighted average of all the downstream representative end-use DFs from which the log type is made. See equation DF-9.

Figure 7: Bar chart showing total potential estimated substitution by region

Figure 8: Table showing potential displacement factor and estimate substitution by region

6.1 Displacement Factor Database

The Carbon Displacement Factor Tool’s underlying database contains five end-use categories with a current total of 101 end-uses, corresponding substitution materials and average DFs with upper 90%/lower 90% limits. It is sourced from Droog et al (in review) which also contains the criteria against which new DFs for materials were or could be included in the future.  These criteria are outlined in Box 1.

6.2 Product to End-Use Allocations

The product to end-use allocations used in the USDA Entity Guidelines (2024) are based on data found in McKeever et al (2011) and McKeever (2009).  A USDA Forest Service-led project to update these allocations is underway but will not be completed in time for the launch of FACT. In the interim, a temporary product to end-use allocation, adapted to the end-uses in this tool, was created from the following sources: 

• Alderman, Delton. 2022. U.S. Forest Products Annual Market Review and Prospects, 2015-2021. Research Note FPL-GTR-289. fpl_gtr289.pdf 
• Taylor, A. , E. Hurmekoski, C. Brandeis, and G. Domke. 2024. Substitution Estimates for Wood Products in the United States, 1990-2020. Forest Products Journal vol 73 (4):362-369. ja_2024_brandies_001.pdf
• CPA. 2024. Downstream Market Report Summarizing Particleboard, Medium Density Fiberboard, Hardboard and Engineered Wood Siding and Trim Products manufactured in the U.S. and Canada.
• CORRIM. 2021. Fibreboard EPD. EPD_North_American_Cellulosic_Fiberboard.pdf (SECURED)
• United States Trade Commission. 2017. Hardwood Plywood from China. Investigation Nos. 701-TA-565 and 731-TA-1341 (final). usitc.gov pub4747

Table 3: Percentage allocations of common U.S. wood products to their end-uses

Table 4: Percentage break-down of three end-use categories into sub-categories

The end-use categories are further broken into sub-end-use categories to match the data in the Carbon Displacement Factor Tool’s underlying database. These are weighted by market share using best estimates and should be marked as highly uncertain. These parameters will be replaced when better data on market shares becomes available. Platform developers welcome any improved data with citations via the feedback form on the web site.

6.3 Forest/Harvested Log to Product Allocations

The data used to create the harvested log-to-primary product ratios are sourced from Smith et al. (2006) Table D6. The non-structural panels in Smith et al (2006) Table D6 were further broken out into particleboard, MDF, hardboard, and fiberboard based on annual production reported in CORRIM LCA reports for each of these products, and then reallocated using the weighted average across the allocation fractions for nonstructural products (see Table 7 from CORRIM report).

Table 4: “Table 7” from CORRIM’s final report to U.S. Endowment representing the re-allocation of nonstructural panels

Table 5: Proportion of total roundwood (softwood/hardwood) in a region converted to a primary wood product

Users are given the option to override the default values and replace them with custom entries as long as they add up to 100%. For example, users from CA, WA, and OR may want to use specific values that can be derived from TPO data  HWP-C-vR/HWP Data/ExistingData at main · jeremygroom/HWP-C-vR · GitHub and found in the Harvested Wood Products Model V.r (HWP Data Visualization).

7.1 End-Use

7.1.1 Calculation of Displacement Factor

Where:

GHGNonWood = Global Warming Potential (GWP) of the non-wood material (in kg C). This value increases proportionally with the quantity of the material.

GHGWood = GWP of the reference wood material (in kg C), selected by the user. This value also scales with quantity.

CarbonWtWood = amount of biogenic carbon stored in the reference wood material (in kg). This value is constant. Note, kg C is 0.5 * kg biomass.

CarbonWtNonWood = amount of biogenic carbon stored in the non- wood material (in kg). This value is constant. 

LifespanNonWood = lifespan of the non-wood product (in years). This value does not change with quantity.

LifespanWood = lifespan of the reference wood material (in years). This value is also constant.

Note: This equation has been adapted from the USDA Entity Guidelines (2024) Equation 5-7 (pictured below) to adjust from functional units with different lifespans.  

7.1.2 Estimate of Substitution

7.1.3 Calculation of Representative DF

Average DF = average of all non-wood DFs in the subcategory

7.1.4 Calculation of Lower Limit and Upper Limit

T-Value dependent on confidence interval (90%) and the number of alternatives per category minus 1.

7.2 Product

7.2.1 Calculation of Displacement Factor 

The weighted displacement factor (DF) for each wood product is calculated by summing the result of the proportion of that product allocated to each end-use multiplied by the representative displacement factor associated with that end-use. This approach weights the overall displacement potential of a product according to how it is distributed across all relevant end-use markets.

7.2.2 Estimate of Substitution

The biogenic carbon in the harvested log is converted from the product default unit to carbon using Smith et al (2006) Table D1: Factors to convert solid wood products in customary units to carbon.

7.3 Forest (Harvested Log)

7.3.1 Calculation of Displacement Factor

The expanded equation for one region_logtype (e.g. PC SW SL) is:

DF_region_logtype =  (α_SWLumber   × DF_SWLumber  )

           + (α_HWLumber   × DF_HWLumber)

           + (α_SWPlywood  × DF_SWPlywood)

           + (α_HWPlywood  × DF_HWPlywood)

           + (α_OSB        × DF_OSB)

           + (α_Particlbd  × DF_Particlbd)

           + (α_MDF        × DF_MDF)

           + (α_Hardboard  × DF_Hardboard)

           + (α_Fiberboard × DF_Fiberboard)

           + (α_OtherIndus × DF_OtherIndus)

           + (α_WoodPulp   × DF_WoodPulp)

Alderman, Delton. 2022. U.S. Forest Products Annual Market Review and Prospects, 2015-2021. Research Note FPL-GTR-289. fpl_gtr289.pdf 

CORRIM. 2021. Fibreboard EPD. EPD_North_American_Cellulosic_Fiberboard.pdf (SECURED)

CPA. 2024. Downstream Market Report Summarizing Particleboard, Medium Density Fiberboard, Hardboard and Engineered Wood Siding and Trim Products manufactured in the U.S. and Canada.

Droog, L. Y., Sonne Hall, E., & Ganguly, I. XXX. Quantifying the climate benefits of wood: U.S.-specific displacement factors across product applications [Manuscript submitted for publication].

International Standards Organization (ISO). 2006. Environmental management — Life cycle assessment — Requirements and guidelines

ISO. 2017. Sustainability in buildings and civil engineering works- Core rules for environmental product declarations of construction products and services. International Organization for Standardization. Second edition (ISO 21930:2017-07) 80pp.

ISO. 2018. Greenhouse gases. Part 1: Specification with guidance at the organization level for quantification and reporting of greenhouse gas emissions and removals.

ISO. 2025. ISO 13391-3:2025 Wood and wood-based products — Greenhouse gas dynamics Part 3: Displacement of greenhouse gas emissions. ISO 13391-3:2025 - Wood and wood-based products — Greenhouse gas dynamics — Part 3: Displacement of greenhouse gas emissions

McKeever D.B. 2009. Estimated annual timber products consumption in major end uses in the United States, 1950-2006. GTR-FPL-181, U.S. Department of Agriculture, Forest Service, Forest Products Lab, 49 p 

McKeever D.B. & Howard, J.L. 2011. Solid wood timber products consumption in major end uses in the United States, 1950-2009 : a technical document supporting the Forest Service 2010 RPA assessment. GTR-FPL-GTR-199, U.S. Department of Agriculture, Forest Service, Forest Products Lab, 39 p.

Murray, L.T., C. Woodall, A. Lister, K. Stockmann, H. Gu, Urbanski, S., Riley, K., Greenfield E., et al. 2024. Chapter 5: Quantifying greenhouse gas sources and sinks in managed forest systems. In Hanson, W.L., C. Itle, K. Edquist. (eds.). Quantifying greenhouse gas fluxes in agriculture and forestry: Methods for entity-scale inventory. Technical Bulletin Number 1939, 2nd edition. Washington, DC: U.S. Department of Agriculture, Office of the Chief Economist.

Smith, James E.; Heath, Linda S.; Skog, Kenneth E.; Birdsey, Richard A. 2006. Methods for calculating forest ecosystem and harvested carbon with standard estimates for forest types of the United States. Gen. Tech. Rep. NE-343. Newtown Square, PA: U.S. Department of Agriculture, Forest Service, Northeastern Research Station. 216 p.

Taylor, A. , E. Hurmekoski, C. Brandeis, and G. Domke. 2024. Substitution Estimates for Wood Products in the United States, 1990-2020. Forest Products Journal vol 73 (4):362-369. Ja_2024_brandies_001.pdf

U.S. Endowment. 2024. CORRIM Embodied Carbon Tool Progress Final Report 12.19.24

US International Trade Commission. 2017. Hardwood Plywood from China. Investigation Nos. 701-TA-565 and 731-TA-1341 (Final). usitc.gov pub4747

Biogenic carbon: Carbon contained in or originating from living or recently living biological material, such as trees, other vegetation, soils and wood products. It is part of the natural carbon cycle and distinct from fossil carbon released from coal, oil and natural gas.

Carbon dioxide equivalents (CO₂e ): A common unit that allows the climate effects of different greenhouse gases to be compared and summed. The quantity of a greenhouse gas is multiplied by its global warming potential (GWP), which expresses its warming effect timbrelative to carbon dioxide over a specified time horizon, conventionally 100 years. The result is reported as the mass of CO₂e that would produce an equivalent climate effect. (Adapted from ISO 14067)

Consortium for Research on Renewable Industrial Materials (CORRIM): A nonprofit research consortium that develops life-cycle inventory and life-cycle assessment data for wood and other renewable materials, including information on forest management, harvesting, wood-product manufacturing, use, and end-of-life pathways.

Conterminous United States (CONUS): The 48 states within the contiguous United States, excluding Alaska and Hawaii. 

Cradle-to-gate: A system boundary that covers production from raw material extraction through manufacturing, ending when the product leaves the factory gate. It includes raw material supply and upstream production, transport to the factory, and manufacturing. It excludes distribution, use, and end-of-life. (Adapted from ISO 21930:2017). 

Displacement Factor (DF): A measure of the GHG emissions avoided when wood is used instead of a functionally equivalent nonwood, fossil-, or petroleum-based material. DFs are estimated by comparing the life-cycle GHG emissions associated with the amounts of wood and nonwood materials needed to perform the same function, with the difference expressed relative to the carbon contained in the wood product. (Adapted from Murray et al., 2024).

Embodied Carbon: The greenhouse gas emissions associated with producing a material or product. 

In FACT, embodied carbon is evaluated on a cradle-to-gate basis, including emissions associated with raw material extraction or harvest, transportation of those materials to the manufacturer and manufacturing of the finished product. It does not include emissions associated with product use, transportation beyond the manufacturing gate, or end-of-life treatment. Embodied carbon also does not include carbon stored in the product itself. (Adapted from American Wood Council, AWC's LCA, EPDs, GWP, and Other Abbreviations Explained) 

Emissions: The total mass of greenhouse gases released to the atmosphere over a specified period. Emissions may occur immediately or over time. For example, a wildfire may cause immediate emissions through combustion of live and dead fuels, followed by additional emissions as fire-killed biomass decomposes. 

End use: The final use or application of a harvested wood product. Primary wood products are allocated among end-use categories to estimate how long carbon remains stored in products in use. Each end-use category is assigned a half-life representing the expected time that products remain in service.

Environmental Product Declarations (EPDs): EPDs assess a product’s environmental performance over its life cycle, taking into consideration carbon emissions due to material extraction, transportation and manufacturing. EPDs are created according to International Organization for Standardization (ISO) guidelines using life cycle assessments (LCAs). 

Forest Inventory and Analysis Program (FIA):A national program of the U.S. Forest Service that conducts continuous, standardized inventories of forest resources across the United States and provides authoritative information on forest extent, composition, structure, growth, removals, and mortality. FIA conducts a variety of inventories, surveys, and reporting activities, including the Nationwide Forest Inventory (NFI), National Resource Use Monitoring (NRUM), National Woodland Owner Survey (NWOS), and Urban Forest Inventory and Analysis (Urban FIA).

Fuelwood: Roundwood harvested for use as an energy source, such as heat, steam or electricity. This category does not include residues or coproducts generated during the processing of sawlogs or pulpwood and subsequently used as fuel; those materials are accounted for as mill coproducts. Fuelwood is classified separately from industrial roundwood.

Greenhouse gasses (GHGs): A gaseous constituent of the atmosphere, both natural and anthropogenic, that absorbs and emits radiation at specific wavelengths within the spectrum of infrared radiation emitted by the Earth's surface, the atmosphere, and clouds, thereby trapping heat in the atmosphere. The greenhouse gases relevant to forest management are carbon dioxide (CO₂), methane (CH₄), and nitrous oxide (N₂O). (Adapted from ISO 14050:2020, 3.9.1) 

Global warming potential (GWP):  A metric that compares the radiative forcing impact of a greenhouse gas to that of carbon dioxide (CO₂) over a specified time horizon (e.g., 20 or 100 years), used to convert emissions into carbon dioxide equivalents (CO₂e). The GWP values applied in FACT reflect those from the IPCC Fifth Assessment Report (i.e., CO₂ = 1, CH₄ = 28, N₂O = 265).

Harvested Wood Product (HWP): Wood removed from the forest ecosystem and entering the HWP accounting system as roundwood, including both industrial roundwood and fuelwood. Logging residues (slash) left on-site after harvesting are excluded.  Under the production approach, HWP calculations are based on underbark volume; therefore bark removed during harvest is not explicitly included in HWP carbon estimates.

Life Cycle Assessments (LCA): A method for systematically evaluating the environmental inputs, outputs, and potential impacts associated with a product system throughout its life cycle. ISO ISO 14040 defines LCA as the “compilation and evaluation of the inputs, outputs and the potential environmental impacts of a product system throughout its life cycle.” LCA is sometimes described as a “cradle-to-grave” approach and can be used to compare products or processes and identify opportunities for environmental improvement. 

Lifespan: Also known as “service life”, this is the length of time a product is expected to last in a functioning end-use. The lifespan is used to specify the functional unit with which to compare two different end-uses. The displacement factor equation includes an adjustment of GWP and biomass carbon for different lifespans.

Log type: A classification of harvested roundwood based on its intended use or processing pathway. FACT distinguishes sawlogs, pulpwood, and fuelwood log types. The classification is based on the roundwood categories and harvested wood product accounting methods described in Smith et al. (2006).

Primary product: A wood product produced from harvested roundwood at the first stage of mill processing, used directly or as an input to manufacture secondary products or end-use products. Primary products include lumber, plywood and other structural and nonstructural panels, oriented strandboard, wood pulp and other industrial products, yielding mill byproducts such as chips and fuel (kerf and sawdust) often used to power dryers and other equipment. Primary products are subsequently allocated to end uses in the model such as wood pulp, packaging and shipping, furniture and new housing. (Adapted from Smith et al. 2006)

Pulpwood: Roundwood intended for processing into pulp, paper, paperboard, or other fiber-or-composite-based wood products. Specifications may vary by region, market and whether dimensions or volumes are expressed on an underbark or overbark basis. 

Sawlog: A log meeting applicable regional or market specifications for diameter, length, and soundness, and where relevant, bark basis, for manufacture into lumber or other solid wood products. Sawlogs are cut from the sawlog portion of sawtimber-size trees.

Substitution: The use of a wood-based product, assembly or structure in place of a functionally equivalent alternative made from other materials, resulting in avoided greenhouse gas emissions. Substitutes are products providing interchangeable value or service in economic or technical terms. The avoided emissions are primarily fossil in origin, since biogenic carbon is accounted for separately. Also referred to as displacement. (Adapted from ISO 21930 / ISO 13391-1)

System boundary: The set of criteria determining what is included in, and excluded from, an assessment.

In greenhouse gas inventory accounting, the system boundary specifies which activities, greenhouse gases and carbon pools are included. It operates alongside spatial boundaries, which delimit the geographic area assessed; sector boundaries, which determine where emissions and removals are reported; and temporal boundaries, which establish the accounting period. (Adapted from Murray et al. 2024)

In life cycle assessment, the system boundary specifies which processes and life cycle stages are included in the product system. For example, a cradle-to-gate boundary includes raw material extraction or harvest through product manufacturing. (Adapted from ISO 14044/Amd1:2017/Amd2:2020.)

For harvested wood products, FACT applies the IPCC production approach, under which HWP carbon is attributed to the location of harvest regardless of where the wood is subsequently processed or used. 

Timber Products Output (TPO): A component of FIA that collects and reports data on timber harvest, product output and wood utilization from primary forest products industries; part of National Resource Use Monitoring (NRUM). See: https://research.fs.usda.gov/programs/nrum