ForewordThe United States Department of Agriculture (USDA) and the United States Department of Energy (DOE) both place high importance on developing resources and conversion technologies for producing fuels, chemicals and power from biomass. The two departments are working together on several aspects of bioenergy. This report is the third to be produced from joint collaboration. This and other reports can be found at: http://www.eere.energy.gov/biomass/publications.html.The website for biomass feedstock research sponsored by the DOE's Office of Energy Efficiency and Renewable Energy Office of the Biomass Program (OBP) can be found at: http:// bioenergy.ornl.gov/. More general information about OBP's feedstock research program can be found at: http://www.eere.energy.gov/biomass/ biomass_feedstocks.html.The website for research and development sponsored by the USDA Forest Service can be found at: http://www.fs.fed.us/ research/.

Landscape ecology deals with the patterning of ecosystems in space. Methods are needed to quantify aspects of spatial pattern that can be correlated with ecological processes. The present paper develops three indices of pattern derived from information theory and fractal geometry. Using digitized maps, the indices are calculated for 94 quadrangles covering most of the eastern United States. The indices are shown to be reasonably independent of each other and to capture major features of landscape pattern. One of the indices, the fractal dimension, is shown to be correlated with the degree of human manipulation of the landscape.

Agricultural residues such as corn (Zea mays L.) stover are a potential feedstock for bioenergy and bio‐based products that could reduce U.S. dependence on foreign oil. Collection of such residues must take into account concerns that residue removal could increase erosion, reduce crop productivity, and deplete soil carbon and nutrients. This article estimates where and how much corn stover can be collected sustainably in the USA using existing commercial equipment and estimates costs of that collection. Erosion constraints to collection were considered explicitly, and crop productivity and soil nutrient constraints were considered implicitly, by recognizing the value of residues for maintaining soil moisture and including the cost of fertilizer to replace nutrients removed. Possible soil carbon loss was not considered in the analysis. With an annual production of 196 million Mg of corn grain (∼9.2 billion bushels), the USA produces 196 million Mg of stover. Under current rotation and tillage practices, ∼30% of this stover could be collected for less than $33 Mg−1, taking into consideration erosion and soil moisture concerns and nutrient replacement costs. Wind erosion is a major constraint to stover collection. Analysis suggests three regions of the country (central Illinois, northern Iowa/southern Minnesota, and along the Platte River in Nebraska) produce sufficient stover to support large biorefineries with one million Mg per year feedstock demands and that if farmers converted to universal no‐till production of corn, then over 100 million Mg of stover could be collected annually without causing erosion to exceed the tolerable soil loss.

Cellulose and maple sawdust have been pyrolyzed by different workers in two different reactors (a fluid bed and a transport reactor) in separate laboratories. The Avicel cellulose sample used by both groups was from the same batch, while the maple was different samples of the same species. Fast pyrolysis product yields were compared at a constant vapor residence time of 500 ms over a temperature range of 450-900 °C and were found to be in very good agreement. It is proposed that if particle heat-up time to 500 °C, for any reactor, is significantly less than particle residence time, or if particle weight loss is less than 10% before the particle temperature reaches 450 °C, then the temperature of the reactor will be the only variable determining the yields of char, oil, and gases for a given feed material and a given gas residence time. The implications of the results in terms of product yields and possible pyrolysis mechanisms are discussed. The oil yield as temperature increases can be described adequately by a simple kinetic model.

Analysis of dead boles of Piceasitchensis (Bong.) Carr. and Tsugaheterophylla (Raf.) Sarg. in open- and closed-canopy forests of the Olympic Peninsula Washington, U.S.A., revealed that hemlock mortality in both forest types was due mainly to windthrow, whereas spruce typically died upright. The open forest contained 120 t/ha of dead bole wood; the closed forest contained 161 t/ha. Hemlock boles decayed more rapidly than the larger spruce boles, although both showed considerable variability. On a per-hectare basis, 146–223 kg of N, 147–197 kg of Ca. 39–61 kg of K, 18–29 kg of Mg, 6–14 kg of Na, and 17–29 kg of P were contained in dead boles of the open- and closed-canopy forests, respectively. Except for N and Mg, the nutrient concentrations of the wood were not significantly different after 33–68 years of bole decay. The N:P ratios increased with increasing decay for both species.

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/ Society needs a quantitative and systematic way to estimate and compare the impacts of environmental problems that affect large geographic areas. This paper presents an approach for regional risk assessment that combines regional assessment methods and landscape ecology theory with an existing framework for ecological risk assessment. Risk assessment evaluates the effects of an environmental change on a valued natural resource and interprets the significance of those effects in light of the uncertainties identified in each component of the assessment process. Unique and important issues for regional risk assessment are emphasized; these include the definition of the disturbance scenario, the assessment boundary definition, and the spatial heterogeneity of the landscape.

ForewordThe United States Department of Agriculture (USDA) and the United States Department of Energy (DOE) both place high importance on developing resources and conversion technologies for producing fuels, chemicals and power from biomass. The two departments are working together on several aspects of bioenergy. This report is the third to be produced from joint collaboration. This and other reports can be found at: http://www.eere.energy.gov/biomass/publications.html.The website for biomass feedstock research sponsored by the DOE's Office of Energy Efficiency and Renewable Energy Office of the Biomass Program (OBP) can be found at: http:// bioenergy.ornl.gov/. More general information about OBP's feedstock research program can be found at: http://www.eere.energy.gov/biomass/ biomass_feedstocks.html.The website for research and development sponsored by the USDA Forest Service can be found at: http://www.fs.fed.us/ research/.