Treesearch

This report presents estimates of the amounts of lumber, glued-laminated lumber, trusses, plywood, particleboard, hardboard, and wood shingles used in new nonresidential building construction in the United States. Use of wood products is shown for several building types, project sizes, and building components. The estimates are based on a survey of 489 projects under construction in 1982-84. Lumber and plywood used per $1,000 of construction were 26 board feet and 21 square feet, respectively. These figures represent an increase over levels reported in 1969.

For international trade, heat sterilization of wood products is often required to prevent the spread of insects and pathogens. Application of heat sterilization requires estimates of the time necessary to heat the center of the wood configuration to the temperature required to kill the insect or other pest. The nature of the heating medium was found to have a significant effect on heating time of slash pine lumber. The heating time increased exponentially with wet bulb depression. When the wet bulb temperature in the heating chamber was below the desired center temperature, heating times...

Prompted by continuing concern that timber-based commodities are becoming increasingly scarce, this paper presents information on changes in real prices (prices deflated by the general producer price index) of timber commodities as potential indicators of economic scarcity. Data updating previous studies are shown for sawlog stumpage, delivered sawlogs, and lumber; pulpwood stumpage, delivered pulpwood, and woodpulp; and delivered veneer logs and plywood. Most real prices were constant or increased somewhat during the two decades after World War Il. Prices have increased more rapidly since...

The Spearfish Creek bridge was constructed in 1992 in Spearfish, South Dakota. It is a single-span, stress-laminated, box-beam superstructure. Performance of the bridge is being monitored for 5 years, beginning at installation. This report summarizes results for the first 3-1/2 years of monitoring and includes information on the design, construction, and field evaluations of the wood moisture content, force level in the stressing bars, behavior under static loading, and overall structure condition. Based on field evaluations, the bridge is performing satisfactorily with no structural or...

The Graves Crossing bridge was constructed October 1991 in Antrim County, Michigan, as part of the demonstration timber bridge program sponsored by the USDA Forest Service. The bridge is a two-span continuous, stress-laminated deck superstructure and it is 36-ft long and 26-ft wide. The bridge is one of the first stress-laminated deck bridges to be built of sawn lumber treated with chromated copper arsenate (CCA) preservative. The performance of the bridge was continuously monitored for 2 years, beginning at the time of installation. This performance monitoring involved gathering and...

The degradation of wood treated with fire retardant (FR) chemicals in roof systems is a problem of major national significance. Understanding of this phenomenon is limited by lack of information on how the performance of FR-treated wood in the laboratory correlates to that of FR-treated wood in the field. In this study, five outdoor field exposure chambers were constructed near Madison, Wisconsin, in the summer of 1991. These structures were intended to simulate the batticsc of multifamily structures for which model building codes sometimes allow the use of FR-treated roof sheathing....

Bolted connections often fail by a shear plug or a splitting beneath the bolt caused by tension perpendicular-to-grain stresses as the bolt wedges its way through the wood. Preventing this type of failure would enhance the capacity and reliability of the bolted connection, thus increasing the overall integrity of a timber structure and enabling wood to compete favorably with other engineering materials. This research investigated the use of fiberglass reinforcement to enhance the load-carrying capacity of bolted wood connections. A series of specimens were prepared from standard 38- by...

The commercial value of several softwood species of the northeastern United States could be increased if these woods could be treated to meet existing American Wood Preserversa Association (AWPA) Standards and used in durable structures. We evaluated the long-term durability of incised and unincised white pine, red pine, eastern spruce, balsam fir, and eastern hemlock treated with ammoniacal copper arsenate (ACA) and chromated copper arsenate (CCA1Type C). The treated wood was exposed above ground and in ground contact in the southern and northeastern United States. Simulated decks were...

To satisfy the increased demand for forest products, much of the future timber supply is expected to be derived from improved trees grown on managed plantations. This fast-grown resource will tend to be harvested in short-age rotations and will contain higher proportions of juvenile wood compared with wood in current harvests. As a result, current allowable properties may need to be reduced in the future. This report explores four options for monitoring the properties of fastgrown wood and briefly discusses the advantages and disadvantages of these approaches. The recommended multiple-stage...

More than 1,200 sawmills produce the bulk of U.S. and Canadian softwood lumber. The maps and tables in this report show the location and size of these mills by State and Province. Analysis of timber inventories in relation to use shows a close correspondence between pricing and use intensity. In some Southern States, the intensity of use is approaching recent growth levels, but the adoption of more intensive management coupled with maturing of large areas of newly established forests should increase supply over the next two decades.