| Literature DB >> 20355695 |
Linda S Heath1, Van Maltby, Reid Miner, Kenneth E Skog, James E Smith, Jay Unwin, Brad Upton.
Abstract
A greenhouse gas and carbon accounting profile was developed for the U.S. forest products industry value chain for 1990 and 2004-2005 by examining net atmospheric fluxes of CO(2) and other greenhouse gases (GHGs) using a variety of methods and data sources. Major GHG emission sources include direct and indirect (from purchased electricity generation) emissions from manufacturing and methane emissions from landfilled products. Forest carbon stocks in forests supplying wood to the industry were found to be stable or increasing. Increases in the annual amounts of carbon removed from the atmosphere and stored in forest products offset about half of the total value chain emissions. Overall net transfers to the atmosphere totaled 91.8 and 103.5 TgCO(2)-eq. in 1990 and 2005, respectively, although the difference between these net transfers may not be statistically significant. Net transfers were higher in 2005 primarily because additions to carbon stored in forest products were less in 2005. Over this same period, energy-related manufacturing emissions decreased by almost 9% even though forest products output increased by approximately 15%. Several types of avoided emissions were considered separately and were collectively found to be notable relative to net emissions.Entities:
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Year: 2010 PMID: 20355695 PMCID: PMC2869221 DOI: 10.1021/es902723x
Source DB: PubMed Journal: Environ Sci Technol ISSN: 0013-936X Impact factor: 9.028
Figure 1The elements of the U.S. forest products industry for its greenhouse gas profile. All wood grown in the U.S. is included in all elements; imported logs processed in mills are also included in elements 3−10.
Forest Ecosystem Area (2005, million ha), Carbon Stocks (2000), and Stock Changes: 2000—2005a
| productivity - owner category | area (million ha) | stocks (PgC) | stock changes (TgC/y) | stock changes (TgCO2-eq./y) |
|---|---|---|---|---|
| all U.S. forests | 248.9 | 25.5 | −125.3 | −459 |
| all timberland | 203.2 | 21.6 | −96.8 | −355 |
| all private timberland | 147.4 | 14.0 | −35.7 | −131 |
| all industry-owned timberland | 27.1 | 2.5 | 3.0 | 11 |
All pools except soil, average annual carbon stock changes; negative number indicates sequestration.
Figure 2Annual changes in carbon in wood and paper products in use and in landfills (TgCO2-eq.) Negative values indicate continued storage out of the atmosphere.
Direct Emissions Associated with U.S. Forest Products Manufacturing Facilities
| direct emissions source | 1990 emissions | 2004 emissions |
|---|---|---|
| fuel consumption at pulp and paper mills | 66.9 | 57.7 |
| fuel consumption at wood products facilities | 4.4 | 1.8 |
| management of mill wastes | 2.0 | 2.6 |
| secondary pulp and paper sector manufacturing operations | 2.8 | 2.5 |
| total | 76.1 | 64.6 |
Emissions of CH4 and N2O from all combustion processes are included. Biomass-derived CO2 is dealt with in the assessment of forest carbon because biogenic carbon is analyzed separately from fossil fuel carbon; an emission factor of zero is used here to avoid double counting.
Estimates based on 1991 fuel consumption data.
Includes CH4 from mill landfills and from anaerobic zones of wastewater treatment plants, not considering the offset from carbon storage in mill landfills (which would lower these numbers).
That is, converting primary products into final products.
Estimates based on 2002 fuel consumption data.
Methane Emitted from Wood and Paper Products in Landfills and Products Made from Wood Harvested in the United States
| CH4 generated (TgCO2-eq.) | net CH4 emitted (TgCO2-eq.) | ||||||
|---|---|---|---|---|---|---|---|
| year | wood | paper | total | fraction recovered/oxidized | wood | paper | total |
| 1990 | 17.1 | 59.1 | 76.2 | 0.20 | 13.7 | 47.2 | 60.8 |
| 1992 | 18.8 | 64.8 | 83.6 | 0.23 | 14.4 | 49.7 | 64.1 |
| 1994 | 20.2 | 70.1 | 90.4 | 0.27 | 14.9 | 51.5 | 66.4 |
| 1996 | 21.8 | 73.5 | 95.3 | 0.31 | 15.0 | 50.6 | 65.6 |
| 1998 | 23.1 | 77.3 | 100.4 | 0.37 | 14.5 | 48.5 | 63.0 |
| 2000 | 24.4 | 80.8 | 105.3 | 0.43 | 13.8 | 45.8 | 59.7 |
| 2002 | 25.7 | 83.0 | 108.7 | 0.46 | 13.8 | 44.6 | 58.3 |
| 2004 | 26.9 | 84.2 | 111.1 | 0.49 | 13.8 | 43.1 | 56.8 |
| 2006 | 28.1 | 85.4 | 113.5 | 0.50 | 14.1 | 42.7 | 56.8 |
Greenhouse Gas and Carbon Profile of the U.S. Forest Products Industry
| greenhouse gas emissions (TgCO2-eq.; negative numbers indicate sequestration) | ||||
|---|---|---|---|---|
| profile element | 1990 | 2004 − 2005 | uncertainty range (%) 2005 | uncertainty range (TgCO2-eq.) 2005 |
| 1. changes in stocks of carbon in forests | 0 | 0 | — | −20 to +20 |
| 2. changes in stocks of carbon in forest products | −132.6 | −108.5 | ±24 | −134.5 to −82.5 |
| 3. direct emissions from forest products manufacturing | 76.1 | 64.6 | ±15 | 54.9 to 74.3 |
| 4. emissions associated with producing fiber | 4.0 | 4.2 | −50 to +100 | 2.1 to 8.4 |
| 5. emissions associated with nonfiber inputs | 24 | 24 | −50 to +200 | 12 to 72 |
| 6. indirect emissions associated with purchased electricity | 42.4 | 43.6 | ±25 | 32.7 to 54.5 |
| 7. emissions related to transport of raw materials and products | 16.9 | 19.6 | −50 to +100 | 9.8 to 39.2 |
| 8. emissions associated with product use | 0 | 0 | 0 | 0 |
| 9. emissions associated with product end-of-life (landfill CH4) | 61 | 56 | −41 to +34 | 33 to 75 |
| 10a. avoided emissions associated with recycling recovered paper | − | −13 to −115 | − | − |
| 10b. avoided emissions associated with using wood-based building materials | − | −7.2 | − | − |
Stable long-term forest stocks are consistent with the data and the principles of sustainable forest management practices on U.S. industrial timberlands. Other privately owned forestlands continue to accrue large amounts of carbon.
Percentage uncertainty is undefined when based on a value of zero.
Bounds based on the best professional judgment of the authors.
Not estimated.