Elaine Oneil

Modeling Biomass Collection and Woods Processing Life-Cycle Analysis*

Abstract A deterministic spreadsheet model developed in an earlier Consortium for Research on Renewable Industrial Materials (CORRIM) project that calculates cost, fuel, and chemical outputs of forest management and harvesting activities was modified to include logic for systems used to recover forest residue. Two illustrative biomass recovery systems with variations were modeled. A system to recover residues after whole-tree harvesting operations was applied to a representative forest stand in the Inland West. Whole-tree chipping in an early thinning was applied to a representative forest stand in the Southeast United States. Emission factors and life-cycle outputs were developed for the systems through the SimaPro v7.3 model using one if its environmental impact methodologies called TRACI2. Most environmental outputs, including global warming potential, had a direct relationship to fuel consumption of the recovery systems. These outputs were subsequently used as inputs to life-cycle analysis in biofuel ...

Comparing Life-Cycle Carbon and Energy Impacts for Biofuel, Wood Product, and Forest Management Alternatives*

The different uses of wood result in a hierarchy of carbon and energy impacts that can be characterized by their efficiency in displacing carbon emissions and/or in displacing fossil energy imports, both being current national objectives. When waste wood is used for biofuels (forest or mill residuals and thinnings) fossil fuels and their emissions are reduced without significant land use changes. Short rotation woody crops can increase yields and management efficiencies by using currently underused land. Wood products and biofuels are coproducts of sustainable forest management, along with the other values forests provide, such as clean air, water, and habitat. Producing multiple coproducts with different uses that result in different values complicates carbon mitigation accounting. It is important to understand how the life-cycle implications of managing our forests and using the wood coming from our forests impacts national energy and carbon emission objectives and other forest values. A series of articles published in this issue of the Forest Products Journal reports on the life-cycle implications of producing ethanol by gasification or fermentation and producing bio-oil by pyrolysis and feedstock collection from forest residuals, thinnings, and short rotation woody crops. These are evaluated and compared with other forest product uses. Background information is provided on existing life-cycle data and methods to evaluate prospective new processes and wood uses. Alternative management, processing, and collection methods are evaluated for their different efficiencies in contributing to national objectives.

Carbon Emission Reduction Impacts from Alternative Biofuels

Abstract The heightened interest in biofuels addresses the national objectives of reducing carbon emissions as well as reducing dependence on foreign fossil fuels. Using life-cycle analysis to evaluate alternative uses of wood including both products and fuels reveals a hierarchy of carbon and energy impacts characterized by their efficiency in reducing carbon emissions and/or in displacing fossil energy imports. Life-cycle comparisons are developed for biofuel feedstocks (mill and forest residuals, thinnings, and short rotation woody crops) with bioprocessing (pyrolysis, gasification, and fermentation) to produce liquid fuels and for using the feedstock for pellets and heat for drying solid wood products, all of which displace fossil fuels and fossil fuel–intensive products. Fossil carbon emissions from lignocellulosic biofuels are substantially lower than emissions from conventional gasoline. While using wood to displace fossil fuel–intensive materials (such as for steel floor joists) is much more effec...

CORRIM: Forest Products Life-Cycle Analysis Update Overview

Since its inception in 1996, the nonprofit Consortium for Research on Renewable Industrial Materials (CORRIM; www.corrim.org) has developed comprehensive environmental performance information on wood building materials consistent with International Organization for Standardization (ISO) standards for life-cycle inventory (LCI) and lifecycle assessment (LCA) research. The majority of prior CORRIM work on structural wood products has been published in two special issues of Wood and Fiber Science (CORRIM 2005, CORRIM 2010) based on data collected and analyzed starting in 1999. Many changes that were likely to affect the life-cycle results have occurred since the mill survey data were collected and compiled for the reports published in 2005 and 2010. These include changes in environmental regulations, both at the manufacturing facilities and in the forests; changes in operational efficiency due to forest sector restructuring after the 2008 economic downturn; and improvements in data quality across the supply chain. Market demand for consistent, transparent information on the environmental footprint of products has expanded greatly over the past decade. In particular, the emergence of environmental product declarations (EPDs) for North American wood products, which are based on specific guidelines as included in product category rules (PCRs), meant that data had to be reported in specific formats to be usable outside the academic community. Taken together, these changes warranted this effort to revisit the 2005 and 2010 research, collect new primary mill survey data, update life-cycle inventory data to reflect current forest management and manufacturing operations, and revise life-cycle impact assessments (LCIA) for development of new EPDs. To that end, this special issue of the Forest Products Journal updates and expands on the prior CORRIM research of six structural wood products, with two regions analyzed for each product. In addition, we develop for the first time an LCA based on primary survey data on boilers used in forest product manufacturing facilities (Puettmann and Milota 2017). We also update regional forest resource life-cycle data for the Pacific Northwest (PNW) region and report on a strategy to develop longitudinal survey methodologies for continuous data collection.

A Life-Cycle Assessment of Forest Resources of the Pacific Northwest, USA*

Abstract Life-cycle inventory (LCI) and life-cycle assessment (LCA) were used to provide quantitative assessments of the environmental impacts of forest management activities that are required to p...

Erratum to: Incorporating Uncertainty into a Life Cycle Assessment (LCA) Model of Short-Rotation Willow Biomass (Salix spp.) Crops

To estimate fossil fuel demand and greenhouse gas emissions associated with short-rotation willow (Salix spp.) crops in New York State, we constructed a life cycle assessment model capable of estimating point values and measures of variability for a number of key processes across eight management scenarios. The system used 445.0 to 1,052.4 MJ of fossil energy per oven-dry tonne (odt) of delivered willow biomass, resulting in a net energy balance of 18.3:1 to 43.4:1. The largest fraction of the energy demand across all scenarios was driven by the use of diesel fuels. The largest proportion of diesel fuel was associated with harvesting and delivery of willow chips seven times on 3year rotations over the life of the crop. Similar patterns were found for greenhouse gas emissions across all scenarios, as fossil fuel use served as the biggest source of emissions in the system. Carbon sequestration in the belowground portion of the willow system provided a large carbon sink that more than compensated for carbon emissions across all scenarios, resulting in final greenhouse gas balances of −138.4 to −52.9 kg CO2 eq. per odt biomass. The subsequent uncertainty analyses revealed that variability associated with data on willow yield, litterfall, and belowground biomass eliminated some of the differences between the tested scenarios. Even with the inclusion of uncertainty analysis, the willow system was still a carbon sequestration system after a single crop cycle (seven 3-year rotations) in all eight scenarios. A better understanding and quantification of factors that drive the variability in the biological portions of the system is necessary to produce more precise estimates of the emissions and energy performance of short-rotation woody crops.

Economics of Multiple Forest Values and Life Cycle Analysis

As climate mitigation efforts transform the value of carbon with institutions creating incentives as well as regulating markets, avoiding unintended consequences becomes challenging. Life Cycle Inventory and Analysis (LCI/LCA) research tracks carbon and other services from the forest to products including displacement of fossil emissions when wood substitutes for fossil fuels or fossil intensive products. Incentives that do not target uses that displace the most emissions will likely steal the feedstock from less effective uses, increasing rather than decreasing emissions. We apply life cycle research to identify leverage points in reducing carbon emissions and their impact on old forest habitat as the ecosystem value most likely threatened by carbon mitigation incentives. Ethanol subsidies, forest carbon credits, and renewable energy standards steal the feedstock from higher leverage uses, while a carbon tax effectively penalizes the largest emitters. Either carbon taxes or incentives will affect the cost of sustaining critical habitat. Institutions need to consider life cycle implications to sustain forests and their multiple values. While a carbon tax provides the proper price signal with the highest reward for the greatest carbon emission reduction, increasing habitat values may be justified to support the production, maintenance and restoration of important habitat.