Wood products have many environmental advantages over nonwood alternatives. Documenting and publicizing these merits helps the future competitiveness of wood when climate change impacts are being considered. The manufacture of wood products requires less fossil fuel than nonwood alternative building materials such as concrete, metals, or plastics. By nature, wood is composed of carbon that is captured from the atmosphere during tree growth. These two effects—substitution and sequestration—are why the carbon impact of wood products is favorable. This article shows greenhouse gas emission savings for a range of wood products by comparing (1) net wood product carbon emissions from forest cradle–to–mill output gate minus carbon storage over product use life with (2) cradle-to-gate carbon emissions for substitute nonwood products. The study assumes sustainable forest management practices will be used for the duration of the time for the forest to regrow completely from when the wood was removed for product production during harvesting. The article describes how the carbon impact factors were developed for wood products such as framing lumber, flooring, moulding, and utility poles. Estimates of carbon emissions saved per unit of wood product used are based on the following: (1) gross carbon dioxide (CO2) emissions from wood product production, (2) CO2 from biofuels combusted and used for energy during manufacturing, (3) carbon stored in the final product, and (4) fossil CO2 emissions from the production of nonwood alternatives. The results show notable carbon emissions savings when wood products are used in constructing buildings in place of nonwood alternatives.

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As part of the Consortium for Research on Renewable Industrial Materials' Phase I life-cycle assessments of biofuels, lifecycle inventory burdens from the production of bio-oil were developed and compared with measures for residual fuel oil. Bio-oil feedstock was produced using whole southern pine (Pinus taeda) trees, chipped, and converted into bio-oil by fast pyrolysis. Input parameters and mass and energy balances were derived with Aspen. Mass and energy balances were input to SimaPro to determine the environmental performance of bio-oil compared with residual fuel oil as a heating fuel. Equivalent functional units of 1 MJ were used for demonstrating environmental preference in impact categories, such as fossil fuel use and global warming potential. Results showed near carbon neutrality of the bio-oil. Substituting bio-oil for residual fuel oil, based on the relative carbon emissions of the two fuels, estimated a reduction in CO 2 emissions by 0.075 kg CO 2 per MJ of fuel combustion or a 70 percent reduction in emission over residual fuel oil. The bio-oil production life-cycle stage consumed 92 percent of the total cradle-to-grave energy requirements, while feedstock collection, preparation, and transportation consumed 4 percent each. This model provides a framework to better understand the major factors affecting greenhouse gas emissions related to bio-oil production and conversion to boiler fuel during fast pyrolysis. This report has been produced as part of the Consortium for Research on Renewable Industrial Materials (CORRIM) Phase I reports on the life-cycle inventory (LCI) and life-cycle impact assessment (LCIA) studies of biofuels. CORRIM's goal is to provide a database of information for quantifying the environmental impacts and economic costs of biofuels from woody biomass through the stages of collection, fuel conversion, and combustion in the United States. Life-cycle assessment (LCA) has evolved as an internationally accepted way to analyze complex impacts and outputs of a product and the corresponding effects on the environment. An LCA can provide the most comprehensive method to assess net carbon emissions and their associated impacts for fossil and biofuels evaluated under similar uses. The environmental outcomes of an LCA can accurately target the source of impacts, including where, when, and how they occur throughout a product's life. The LCA process can provide characteristics such as global warming potential (GWP) and fossil fuel use that can be useful on a regional, national, or global scale. Outcomes from LCAs can be used to suggest more ''environmentally friendly'' products or sustainable production methods and may also provide insights regarding raw material conservation and emissions and waste output reduction. LCIA aggregates the inventory data and classifies them into the type of environmental impact to which they contribute, for example, GWP. Comparisons of the emission outputs of bio-oil with a relevant fossil fuel

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The goal of this study was to estimate the greenhouse gas (GHG) emissions and fossil energy requirements from the production and use (cradle-to-grave) of bioethanol produced from the indirect gasification thermochemical conversion of loblolly pine (Pinus taeda) residues. Additional impact categories (acidification and eutrophication) were also analyzed. Of the life-cycle stages, the thermochemical fuel production and biomass growth stages resulted in the greatest environmental impact for the bioethanol product life cycle. The GHG emissions from fuel transportation and process chemicals used in the thermochemical conversion process were minor (less than 1 percent of conversion emissions). The net GHG emissions over the bioethanol life cycle, cradle-to-grave, was 74 percent less than gasoline of an equal energy content, meeting the 60 percent minimum reduction requirement of the Renewable Fuels Standard to qualify as an advanced (second generation) biofuel. Also, bioethanol had a 72 percent lower acidification impact and a 59 percent lower eutrophication impact relative to gasoline. The fossil fuel usage for bioethanol was 96 percent less than gasoline, mainly because crude oil is used as the primary feedstock for gasoline production. The total GHG emissions for the bioethanol life cycle analyzed in this study were determined to be similar to the comparable scenario from the Greenhouse Gases, Regulated Emissions, and Energy Use in Transportation model. A sensitivity analysis determined that mass allocation of forest establishment burdens to the residues was not significant for GHG emissions but had significant effects on the acidification and eutrophication impact categories.