This study involves the use of supercritical methanol (SCM) processing as a means of converting ponderosa pine biomass into usable fuels and chemicals. SCM treatments were performed in a batch type reactor at temperatures close to and above the critical point (238 C and 8.3 MPa) to induce degradation of the biomass. Analytical tools such as GC-MS and GPC were employed to characterize, respectively, the volatile components and non-volatile depolymerized materials after treatment. Data shows that the degradation of biomass in supercritical methanol is capable of achieving above 90% conversion of solid biomass into a methanol soluble fraction, with varying molecular weight distributions. Experimental conditions and further results will be discussed.
Abstract A sizable body of literature concerned with technological substitution modeling exists within the domain of forest products. These models have generally been used to develop market share forecasts for various forest products and their substitutes based on relative product prices. Substitution models usually assume that the potential market size is known and that products can freely substitute for one another. A small but growing literature concerned with the diffusion of innovations also exists within the domain of forest products. This diffusion literature typically focuses on factors affecting consumer acceptance for product innovations and forecasting the level of demand growth without constraining the potential market size. In this paper, we examine the dynamic sales behavior of three and four successive generations of structural wood panel products using varying forms of a multigeneration diffusion model. The multigeneration diffusion model introduced here, which encompasses the elements of diffusion and substitution modeling, assumes that a new structural wood panel product will diffuse through a population of potential consumers over time and that market share competition will be introduced with successive generations of structural wood panels. It is important to note that our results are contingent upon the use of domestic production data, which is used as a proxy for domestic consumption. In other words, our results do not factor in net imports. Estimation results indicate that market share competition between various structural wood panel products are differentially impacted by substitution and diffusion effects. We explore the managerial implications of the model results and suggest alternative multigeneration diffusion models that could be developed for structural wood panel products. For. Sci. 45(2):232-248.
This study uses the Engle–Granger cointegration method to examine the correlation relationship among prices of North American softwood lumber species, wood-based panel prices, and US single-family housing starts. The methodology employed is identical to that used by US petitioners in the latest round of the Canada – United States softwood lumber trade dispute, whereby petitioners argued that all North American species of softwood lumber were considered to be nearly perfect substitutes for one another. Tests for nonstationarity using the augmented Dickey–Fuller unit root test, as well as our cointegration results, confirm petitioners’ results. We find evidence of a long-term cointegrating relationship among the prices of North American softwood lumber species. However, we found no clear evidence of nearly perfect substitutability among different North American softwood lumber species. Additional analysis reveals that a long-run equilibrium relationship also exists between North American softwood lumber species and four types of wood-based panel products, as well as US single-family housing starts. Given that the price movements of different wood-based panel products and single-family housing starts are highly correlated with the price movement of North American softwood lumber species, we fail to conclude that North American softwood lumber species can be claimed as nearly perfect substitutes. Furthermore, we find that the petitioners’ analysis is deficient in that it does not account for the fact that cointegration in prices among North American species of softwood lumber can be caused by common demand-side factors, such as residential construction activity.
Eighteen-hundred g rand fi r ( Abies grandis) studs, curve sawn from small-diameter [approximately 4-7 inches (102-178 mm)] sawlogs, were kiln dried to determine effects of drying schedule and restraint on energy consumption, drying time, and warp (bow, crook, and twist). The experimental design included 18 kiln charges with three replications of t hree k iln s chedules. Nine of the kiln c harges were restrained a nd nine were unrestrained. Kiln schedules were high-temperature [240° F (116° C) dry bulb with no venting or steam spray], elevated [190-220° F (88-104° C) dry bulb and 190-165° F (8874° C) wet bulb], and conventional [180° F (82° C) dry bulb and 170-145° F (77-63° C) wet bulb]. Restraint loading was 200 pounds per square foot (psf) (976 kg/m ). 2 Results showed that the high-temperature schedule consumed approximately one-third and one-half of the energy of the elevated and conventional schedules, respectively. In addition, drying time averaged 21.1 hours with the high-temperature schedule, 42.0 hours with the elevated schedule, and 50.3 hours with the conventional schedule. Although there were several significant differences in bow, crook, and twist in lumber dried by the three schedules, no schedule showed significantly lower warp. Results also showed that restraint reduced warp in lumber in the high-temperature and elevated schedules, and much of th e warp reduction was in lumber w ithin the top six courses of t he stack. In addition, restraint reduced the variance of warp in lumber dried by all three schedules.
Material substitution in the residential construction industry is driven by a variety of factors including product availability, product performance, price, price stability, and in-place costs. As competition between softwood lumber and substitute products increases, managers need to understand end-users' changing perceptions of softwood lumber and the competitive position of softwood lumber vis a vis substitute products. This exploratory study was developed to assess the competitive relationship between softwood lumber and substitute products in structural end-use applications in the U.S. residential construction industry. In particular, the study was designed to identify those product attributes that are perceived by residential contractors to be important in influencing the substitution process. Over 90 percent of the respondents indicated that they had used at least one substitute product for softwood lumber in structural end-use application. Despite this, respondents indicated that their use of structural softwood lumber is changing only moderately. The analysis of the data indicates that product strength and straightness were rated the most important factors, while price and price stability were also rated highly. A principal components factor analysis ofthe 12 product attributes identified 3 underlying factors that influence the material substitution process : the physical characteristics of the product, the technical characteristics of the product, and economic/supply characteristics of the product. Interested persons may contact the authors for a copy ofthe survey questionnaire.
The U.S. residential construction industry, traditionally the largest end-use market for softwood lumber, has undergone a period of rapid change over the past decade. The effects that timber harvest restrictions in federal and state forests have had on softwood lumber price, price volatility, and lumber quality, combined with technological advances employed by the manufacturers of substitute materials, have contributed to the increased use of substitute materials in residential construction. The objective ofthis research was to assess the extent of material substitution in residential construction between 1994 and 1998, as well as to provide insight into the factors driving the changes in material substitution. Results of this study are based on a random sample of 2,400 U.S. residential construction firms and a census of the 100 largest U.S. residential construction firms. Results are directly compared with data collected from an identical survey that was conducted in 1995. This study offers convincing evidence that softwood lumber continues to lose market share in the U.S. residential construction industry and that builders remain concerned about softwood lumber quality, price, and price stability. Additionally, this study reveals that builder impressions regarding the environmental impact of substitute materials, including steel and concrete, have become increasingly favorable relative to softwood lumber over the analyzed time frame.
This paper utilizes a world spatial equilibrium model to examine the effects of U.S.–Canadian softwood lumber disputes on U.S., Canadian, and other exporters' and importers' lumber markets. Results show that the U.S. import tariff on Canadian softwood lumber impacts prices, supply, demand and trade flows not only in the United States and Canada but also in the other countries. Though the goal of U.S. trade restriction is to limit imports from Canada and protect its producers, the United States cannot fully accomplish this goal as non‐Canadian exporters fill the void left by the reduced imports from Canada. Canadian producers lose from the U.S. policy, but their loss is mitigated as Canada redirects its exports to other importers. Importing countries such as Japan and the European Union benefit from the U.S. trade restrictions as Canada seeks to sell its softwood lumber to these countries.
