Minnesota’s Forest Carbon & Life Cycle Assessment Dashboard

The Minnesota Forest Carbon and Life Cycle Assessment dashboard presents in-forest and life-cycle assessment (emissions) information related to carbon storage and sequestration in Minnesota forests and harvested wood products. The Forest Vegetation Simulator (USDA-Forest Service) was used with USDA-FIA forest inventory and analysis data for Minnesota from 2017-2021 to project forest growth and harvesting 100 years into the future. Harvested wood product contributions to net storage are included in the projections. Additionally, product end-of-life alternatives are considered up to 200 years beyond the useful life of the product.
Explore the Dashboard

Results show that forest management activities within Minnesota’s diverse forest types contribute to long-term carbon storage both within forests and in harvested wood products. Models for business as usual, economic intensive, climate adaptive, and no management strategies all predicted increased annual carbon sequestration and storage over the next 25 years. While increased management scenarios corresponded to lower in-forest stocks in general, they also produced positive sequestration trends going forward. Quantification of harvest leakage and product substitution effects reveals an important consideration of the benefits of managed forests. These nuances of forest carbon outcomes can now be weighed with management approaches seeking to balance ecological, wildlife, economic, and many other benefits Minnesota forests provide.

For more project information including a full description of data, methods, and results, please see the final project report. For data, and associated descriptions, that the dashboard was based on, consult the master data spreadsheet. Questions and feedback can be emailed to the Minnesota Forest Resources Council at mfrc.info@state.mn.us.

Interpreting the Dashboard

Forest Types
Minnesota forests contain many different forest types that describe forest cover as either dominated by a single tree species or as groupings of several species. The dashboard presents information about the following eight forest types that represent broad forest cover found in Minnesota:
- Aspen/birch
- Red pine
- Upland spruce/fir
- Oak
- Northern hardwoods
- Lowland conifers
- Black ash*
- Other**
* Black ash was included due to its important ecological role and the peril facing the species from the invasive emerald ash borer. Black ash grows well in saturated soils, providing important hydrologic services, habitat structure and function, and is an important traditional source of fiber for crafts, basket weaving, and other uses.

** "Other" forest type contains all other forest cover types to ensure the accounting of all carbon across the landscape.

Forest Management Scenarios

Within each forest type, five different forest management scenarios and associated silvicultural prescriptions are modeled, providing information on how potential shifts in management can impact carbon flux. Silviculture prescriptions refer to planned treatment of a forest site designed to change stand structure or condition to meet management goals. Modeling results from the management scenarios suggest how forest management activities might be adjusted to increase the carbon storage potential of forests. Note that all management scenarios occur on varying acreages in Minnesota based on ownership and management directive. The following table provides an overview of each of the management scenarios.

Forest Management Scenario	Description
No management	No management treatments were applied in this scenario. While this scenario projected an increase in the amount of carbon stored within Minnesota’s forests, it showed a decline in carbon storage rates over time. No management can compromise the forest’s ability to adapt and be resilient to climate changes.
Business as usual (BAU)	Silvicultural prescriptions were identified according to typical management strategies used in Minnesota. Harvests occurred at a rate identified by historical timber harvests. This scenario incorporates the other three management scenarios (i.e., no management, climate-adapted, and economic intensive) to the extent they are currently being applied on Minnesota’s forests.
Increased harvest	Additional harvest and growth runs were modeled in FVS at approximately the maximum sustainable harvest rate identified in the 1994 Generic Environmental Impact Statement on Harvesting and Forest Management in Minnesota. Increased harvest projections were developed for business as usual, climate-adapted, and economic intensive silvicultural scenarios.
Climate-adapted	Silvicultural prescriptions were identified for each forest type that sought to promote forest resilience under an adaptive silviculture strategy. Characteristics included tree planting, shorter entry periods (i.e., the interval between harvesting operations), and managing for diverse species and stand ages.
Economic intensive	Silvicultural prescriptions were identified that sought to maximize economic return from forest management activities. Characteristics included shorter rotation (i.e., the planned number of years between formation of a stand and its final harvest a specified stage of maturity*) ages and increased harvest intensities.

*Jones, John R.; Shepperd, Wayne D. 1985. Rotations. In: DeByle, Norbert V.; Winokur, Robert P., editors. Aspen: Ecology and management in the western United States. USDA Forest Service General Technical Report RM-119. Rocky Mountain Forest and Range Experiment Station, Fort Collins, Colo. p. 217-218

View silvicultural prescriptions specifics modeled for each forest type.

Dashboard Abbreviations and Glossary

Following are abbreviations and terms used in the Minnesota Forest Carbon Baseline and Life Cycle Assessment Dashboard to characterize different forestry and greenhouse gas modeling concepts.

Abbreviations

ac	acre
BAU	Business as usual
CA	Climate-adapted
CO2	Carbon dioxide
CO2-eq	Carbon dioxide equivalent
Econ	Economic intensive
EOL	End-of-Life
FIA	Forest Inventory and Analysis
HW	Hardwood
HWD	Hazardous waste disposed
HWP	Harvested wood product
kg	Kilogram
LCA	Life Cycle Assessment
MMT	million metric tons
MMtn	million metric tons
Mt	metric tons
OSB	Oriented Strandboard
SW	Softwood
SWDS	Solid waste disposal sites
Tonne	metric ton

Glossary

Aboveground biomass. All living biomass above the soil including stems, stumps, branches, bark, seeds, and foliage (Domke et al. 2023).

Belowground biomass. All living biomass of coarse living roots with diameters greater than 2 millimeters (Domke et al. 2023).

Basal area. The cross-sectional area of woody stems growing within an area of interest. Basal Area is typically expressed in square feet of cross-section area per acre.

Biomass. Organic material, living or dead, such as trees, crops, grasses, tree litter, and roots (Russell et al. 2022).

Carbon flux. The measurement of change in forest carbon stock between two time periods. Also called “net carbon flux” (Minnesota DNR 2023).

Carbon pool. A part of a system that can store, accumulate, or release carbon. Five carbon pools are commonly used to describe forest carbon pools: aboveground biomass, belowground biomass, soil, litter, and dead wood (Domke et al. 2023).

Carbon sequestration. The process by which trees and other plants use carbon dioxide and photosynthesis to store carbon as plant biomass.

Carbon storage/stock. The amount of carbon in a tree or forest. Reflects a physical amount of carbon that is the result of sequestration.

CO2-eq/Carbon dioxide equivalent/CO2 equivalent. Unit for comparing the radiative forcing of a greenhouse gas to that of carbon dioxide (ISO 14067).

Cradle to Gate. Covers the mandatory production stage that includes the following information modules: extraction and upstream production (raw material supply), transport to factory and manufacturing (ISO 21930:2017).

Embodied carbon. The global warming impact of all the greenhouse gas emissions through production of the product. Usually displayed in mass of CO2 equivalents (e.g., kg CO2-eq.)

Emission. Release of carbon into the atmosphere.

End of Life. Used to refer to harvested wood products that have reached the end of their intended use such as discarded, recycled or repurposed wood.

HWP In-Service. Harvested wood products that are currently in use and are storing carbon.

Life cycle assessment (LCA). Compilation and evaluation of the inputs, outputs, and the potential environmental impacts of a product system throughout its life cycle (14040:2006/Amd1:2020).

Life cycle inventory (LCI). Phase of life cycle assessment involving the compilation and quantification of inputs and outputs for a product throughout its life cycle (14040:2006/Amd1:2020).

Life cycle impact assessment (LCIA). Phase of life cycle assessment aimed at understanding and evaluating the magnitude and significance of the potential environmental impacts for a product system throughout the life cycle of the product (14040:2006/Amd1:2020).

Leakage. Accounts for likely carbon outcomes of making the choice to reduce or eliminate management from Minnesota’s forests and the likelihood that harvest will then be shifted to another region to meet timber demand.

Soil carbon. All organic material in soil to a depth of 1 meter but excluding the coarse roots of the belowground pools.

Substitution. The difference between functionally equivalent materials (e.g., steel stud vs wood stud) measured in carbon equivalents.

For a complete list of abbreviations and glossary for the Minnesota forest carbon research project, see the project report: “Estimating current and future carbon stocks and emissions in Minnesota forest and forest products under multiple management scenarios” Section 8: Appendices.

Understanding Project Scope: Constraints and Considerations

Careful consideration should be given when interpreting results from the dashboard. The forest projections could not directly model all the influences on carbon storage and flux within the forest. Therefore, several assumptions had to be made regarding these unmodeled natural processes, activities, and other factors that affect forest carbon. In addition, the study focused on a specific range of management goals and resulting actions. To be sustainable, forest management must balance all forest resources (e.g., wildlife habitat, healthy watersheds, forest products industry and jobs, cultural values, and outdoor recreation). Managing forests for a single outcome can lead to loss of other ecological, economic, cultural, and social benefits they provide.

The following table summarizes implications of the research’s assumptions on interpreting results presented in the dashboard.

Major Assumptions	Implications for Interpreting & Applying Results
Management Goals	This project focuses on different outcomes related to one possible management goal: carbon storage and sequestration. However, in practice, forest practitioners and landowners consider many other objectives. Typical forest management seeks to balance diverse goals. Interpretation and application of project results must acknowledge other factors influencing forest management decisions.
Management Scenarios	The management scenarios modeled in the study were selected to provide a range of silvicultural approaches and management goals. Interpretation of results should include the understanding that scenarios reflect "what if" situations, rather than expected future management.
Catastrophic Disturbances	The effects of frequent prescribed fire and spread of emerald ash borer were modeled directly. In addition, the Forest Inventory and Analysis (FIA) data used to calibrate the model includes information from all stand histories, and thus models will reflect the effects of low to moderate disturbances. However, simulating stand-replacing disturbances such as insect outbreaks, drought, windthrow, and wildfire can be assumed absent aside from 20-year average disturbance related mortality rates informed by FIA monitoring. When assessing results, interpretations should consider the risk and potential effects of large disturbances on the carbon stored in-forest and in harvested wood products.
Changing Climate Conditions	Simulating the effects of changing climate conditions on carbon pools, species composition, disturbance related mortality, or wildfire risk was beyond the scope of this project. Interpretations of results should understand that climate conditions were assumed constant and consider the implications of changing conditions when drawing conclusions.
Area, Volume, & Product Control	Forest management scenarios that included harvest were controlled to project relative departures from current levels of harvest by acres and volume over time. Annual harvest entries were held roughly constant across the projection period for BAU to allow direct comparisons between the scenarios. The mix of harvested wood products currently produced in Minnesota were also held constant through time. Additionally, it was assumed that the 2021 above ground and harvested carbon should have the same total for all scenarios. Other considerations beyond the scope of this project included raising the harvest levels to maximize sustainable fiber supply, expanding acres managed in a given year, introducing new mills or other wood processing infrastructure, adding alternative forest products, and changing market conditions. Implications of changing harvest levels and economic factors should be considered when interpreting study results.
Prescribed Fire	The prescribed fire results from this study should be evaluated considering the many other factors surrounding using fire as a management tool, as well as assumptions used by FVS to project combustion of duff, organic soils, and coarse fuels under prescribed or cultural fire conditions. Another important consideration is that the large number of acres subjected to prescribed burning in the model is probably not achievable in real life, so overall emissions would be lower. Also, the number of personnel and acres treated is modeled after documentation from a prescribed burn on the Otter Creek unit of the Cloquet Forestry Center. This was a training burn and may not be representative of staffing or equipment levels used in other prescribed fires.
Black Ash Decline	The business as usual (BAU) and climate adaptive scenarios for black ash assumed no increased mortality from emerald ash borer. In the future, if weather remains prohibitively cold for the borer to spread north, these baseline simulations will appropriately reflect those conditions. However, under the assumption that temperature will not substantively restrict the spread of the borer, the BAU/Climate-adapted scenarios with increased mortality will better reflect those conditions. However, under the increased mortality scenario, the expected swamping effect was not modeled. If black ash are removed from a hydric ecosystem, they will no longer transpire significant amounts of water during photosynthesis, leading to several studies suggesting the water table will rise. This increase in water levels may drown the roots of other tree species, effectively turning black ash stands into open wetlands. Readers should consider the potential swamping effect when interpreting results for black ash.
Landscape (Not Stand) Scale	The Forest Vegetation Simulator (FVS) projections of each silvicultural scenario represent effects across all acres of a particular forest type. The treatments were applied to every whole condition plot in the FIA database, and the resulting trendlines show the average per acre response across all sites. Application of the silvicultural prescriptions to individual stands might provide results that look very different. Thus, interpretation of the FVS projections should emphasize the collective response of a forest type across Minnesota and not assume individual stands will necessarily respond the same way.
Substitution & Leakage Effects	In the LCAs, substitution effects refers to the carbon benefit of using wood (carbon sink) versus another carbon intensive product (carbon source). For example, using wood studs instead of steel studs to construct a building. Accounting for substitution becomes more critical under the No management scenario, as alternative products will be needed to replace those previously supplied by wood fiber. Alternatively, the wood supply could come from outside sources (e.g., Wisconsin) (termed “leakage”). Comparisons between silvicultural scenarios with and without management should recognize the broader implications of substitution and leakage effects when interpreting results.

For the complete list and discussion of caveats and limitations of the Minnesota forest carbon research project, see the project report: “Estimating current and future carbon stocks and emissions in Minnesota forest and forest products under multiple management scenarios” Section 2.4: Caveats/Limitations.