Wood in Our Future: The Role of Life-Cycle Analysis Proceedings of a Symposium (1997) / Chapter Skim
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ASSESSING ENVIRONMENTAL IMPACTS OF WOOD USED AS A RAW MATERIAL IN NORTH AMERICA
ASSESSING ENVIRONMENTAL IMPACTS OF WOOD USED AS A RAW MATERIAL IN NORTH AMERICA
Pages 27-35
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From page 27... ...
In this sense, therefore, wood is not a raw material, but an intermediate material obtained from trees extracted from the forest. The soil, minerals, air, and water of the forest provide the basic raw materials and the environment for growing trees, and it follows that the boundary for LCA studies involving wood must include the forest operations.
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From page 28... ...
The Canadian Standards Association has initiated some work in this arena including studies aimed at selecting inexpensive and effective methods for obtaining impact data. FIREWOOD AND ENERGY Firewood, the simplest wood product, raises important issues.
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From page 29... ...
(Here, it is relevant to note that compared with burning fuel oil the burning of wood is cleaner; it produces fewer oxides of sulfur and less ash, for example.) Thus: ~ Trees convert primary compounds to wood a valuable raw or intermediate matenal.
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From page 30... ...
These include the use of renewable wood as a raw material to generate heat and electrical energy in power stations, to manufacture chemicals, or to produce alternative nonfossil fuels for automobiles, for example. These developments will affect not only the carbon cycle but, among other things, will also affect SOx emissions, land use, and social systems.
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From page 31... ...
As a hypothetical partial example, consider processes A through D shown in Table 3-2. TABLE 3-1 Impact categories and chains Stressor Primary Secondary Tertiary Quaternary SOx Acid rain Building deterioration Resources Water quality Aquatic biota Reduced diversity Vegetation effects Agricultural production and fishing Soil effects Vegetation effects
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From page 32... ...
Referencing processes B through D, extracted from Table 3-2, for example, we obtain the results shown in Table 3-3. The application of equivalence factors allows each impact category in matrices like that shown in Table 3-2 for operations A through D to be described in TABLE 3-3 Hazard potential Operation Item B C D Gas Weight Equivalence factor co2 w co2 CHA z 1 1 lla Total stressor in CO2 units = [w + y + 1 l*
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From page 33... ...
For example, in handling acid rain it has been shown that, by studying maps showing areas that have sensitive soils and by identifying regions with large acid gas emissions, it is possible to develop weighting factors (similar to the equivalence factors discussed above) to express regional differences across the continental United States (see Figure 3-2~.
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From page 34... ...
are already available for study. Valuation Once final total characterized stressor values are calculated, it is necessary to determine their relative significance.
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From page 35... ...
· Wood offers opportunities to produce energy, chemicals, and alternative fuels while reducing increases in atmospheric CO2 concentrations. · Computational methods for assessing impact currently permit a fair degree of comparison to be made between the impacts of systems.
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