Treesearch

A critical factor in the fire endurance of a wood member is its rate of charring. Most available charring rate data have been obtained using the time-temperature curves of the standard fire resistance tests (ASTM E 119 and ISO 834) to define the fire exposure. The increased use of heat release calorimeters using exposures of constant heat flux levels has broadened the available database on wood charring. This paper presents such char rate data obtained with an Ohio State University (OSU) calorimeter. Results include char depth versus time models, char rates as function of other parameters,...

This report presents information on the contribution of the extractive industries to the domestic economy at different geopolitical scales. Areas where resource production is important to gross state or regional product, employment, or income are highlighted. Output, employment, value added, and personal and total income multipliers are reported for the energy and mineral sectors.

Wood degradation and defects, such as voids and knots, affect the quality and processing time of lumber. The ability to detect internal defects in the log can save mills time and processing costs. In this study, we investigated three nondestructive evaluation techniques for detecting internal wood defects. Sound wave transmission, x-ray computed tomography, and impulse radar were used to examine white spruce and balsam fir logs. Computed tomography resulted in the highest resolution for voids, knots, and high moisture content areas, but at a very high price. Both sound wave transmission...

In the United States, timber and agriculture are two important components of the Gross Domestic Product (GDP). The purpose of this study was to quantify the volume and value of timber in the U.S. economy in 1991 and compare the value of timber with that of agriculture. Combined, timber and agriculture accounted for 6.2 percent of total GDP in 1991, and 13.2 percent of the goods and structures portion of GDP. Primary timber products production totaled 17,889 million ft.3 in 1991 and was valued at $19,370 million. Primary agricultural products were valued at $156,094 million in 1991....

This report describes the current status of wood and paper recycling in the United States and predicts the production and market consequences of increased recycling. The results suggest that the rate of paper recycling will rapidly rise in the 1990s, mainly as a result of the competitive evolution of fiber markets and papermaking technologies. The consumption and export of paper and paperboard are also projected to grow, but imports are projected to generally decline. In the context of increased paper recycling, the production of lumber and structural wood panels is projected to increase....

Structural and nonstructural panel products have constituted the fastest growing segment of the wood products industries over the past two decades. Based on announced plans, growth will accelerate in the next 2 years. The cost of wood fiber used in these processes has been rising. To keep wood costs as low as possible, a growing share of the new production is being channeled into regions where panel manufacturing has been low or nonexistent and where underutilized timber supplies are still available. There is also increasing interest in using agricultural fibers for panels, either to...

A large part of the forests located in the Rocky Mountain region of the U.S. West (inland West) is characterized by densely packed, small-diameter stands. The purpose of this study was to examine the economic feasibility of using small-diameter material from this resource to manufacture various wood products: oriented strandboard (OSB), stud lumber, random-length dimension lumber, machine-stress rated random-length lumber, laminated veneer lumber (LVL), and market pulp. The analysis indicated that LVL promises the best ratio of revenue to wood input, followed by market pulp and OSB. Among...

The Federal Highway Administration and the USDA Forest Service, Forest Products Laboratory, jointly sponsored the National Conference on Wood Transportation Structures, October 23-25, 1996, in Madison, Wisconsin. This was a direct result of 5 years of cooperation in conducting research related to timber transportation structures. The objective of the conference was to present state-of-the-art information on wood utilization in transportation applications. The conference included a plenary session, reviewing timber bridges throughout the world, followed by concurrent paper sessions on...

Brown-rot fungal antigens were detected by particle capture immunoassay(PCI) in southern pine 2 X 4’s beyond visible or culturable hyphal growth. Further analysis of test samples revealed changes along the 2 X 4’s that could be grouped into zones. Zone 1, the point of inoculation through 6 cm, showed low pH, measurable oxalic acid, high moisture, and high protein. Zone 2, through 16 cm, marked the end of visible hyphal growth, increased permeability, viable fungi isolated by culturing, and detection by microscopic examination. Zone 3, through 71 cm, revealed increased alkali solubility....

Agro-based resources, also referrered to as lignocellulosics, are resources that contain cellulose, hemicelluloses, and lignin. Lignocellulosics include wood, agricultural residues, water plants, grasses, and other plant substances. When considering lignocellulosics as possible engineering materials, there are several very basic concepts that must be considered. First, lignocellulosics are hygroscopic resources that were designed to perform, in nature, in a wet enviornment. Secondly, nature is programmed to recycle lignocellulosics in a timely way through biological, thermal, aqueous,...