Treesearch

Wood is the major source of fiber supply. Non-wood fibers are mainly used in papermaking where there is a lack of forest resource such as in China and India. Cornstalk, among the agricultural residues and other non-wood fiber, is the most promising source of fiber. However, The usage of cornstalks is very limited in pulp and paper industry, although nearly 284 million tons/year are available worldwide, including 150 million tons/year in the United States. Cornstalk contains about 27% hemicelluloses, which is higher than most of the hardwoods and non-wood fiber materials. Preservation of...

Use of wood-based-composites technology to create value-added commodities and traditional construction materials is generally accepted worldwide. Engineered wood- and lignocellulosic-composite technologies allow users to add considerable value to a diverse number of wood- and lignocellulosic feedstocks including small-diameter timber, fast plantation-grown timber, agricultural fibre and lignocellulosic residues, exotic-invasive species, recycled lumber, and timber removals of hazardous forest-fuels. Another potential advantage of this type of economic- and materials-development scenario is...

Wood is a naturally formed organic material consisting essentially of elongated tubular elements called cells arranged in a parallel manner for the most part. These cells vary in dimensions and wall thickness with position in the tree, age, conditions of growth, and kind of tree. The walls of the cells are formed principally of chain molecules of cellulose, polymerized from glucose residues and oriented as a partly crystalline material. These chains are aggregated in the cell wall at a variable angle, roughly parallel to the axis of the cell. The cells are cemented by an amorphous material...

Small, rural forested communities have the economic need to develop a wood products industry to replace the loss of large sawmills and maintain forest health. The main objective of this study was to explore the potential of using producer (wood) gas to fire a hot water boiler for a small dry kiln capable of drying both softwood and hardwood lumber. A BioMax wood gasifier, a hot water boiler, and dry kiln were integrated as parts of a whole lumber drying system for a field test in southwestern United States. Results so far found the amount of gas heat produced from the wood chip-fed BioMax...

Since the interior of a charred wood member normally retains its structural integrity, large structural wood members often do not need to be replaced after a fire. Engineering judgement is required to determine which members can remain and which members need to be replaced or repaired. Due to the lack of established methods to directly determine the residual capacity of damaged wood members, a systematic approach starting with the assessment of the likely fire exposure is recommended. Assessment includes visual inspection of damaged members, visual inspection of connections, and visual...

Traditional hardwood lumber drying processes were developed for appearance-type products such as furniture, cabinetry, and millwork. This means that air-drying practices were managed to minimize the chemical and fungal stains that occur in white woods such as maple, as well as surface checking that is common in some species. It also means that the kiln schedules which were developed are conservative, slow, and designed to virtually eliminate even minor drying defects such as small surface checks or discolorations. In structural products, surface checks and discoloration do not detract from...

A significant volume of softwood lumber is used in engineered truss assemblies. Metal plate connected (MPC) trusses are commonly used in residential construction for both roof and floor applications. Currently, there are no truss manufacturers producing MPC trusses with hardwood lumber, primarily as a consequence of a lack of technical data on the performance of hardwood material in MPC trusses. This chapter presents information that is critical to using hardwood lumber in MPC trusses. It summarizes results from several testing and demonstration studies and includes information on estimated...

The purpose of the work reported in this chapter was to examine the flexural properties of LVL manufactured from ultrasonically rated red maple veneer sheets. The specific objectives were: 1. to determine the flatwise and edgewise bending properties of ½ inch-(1.3-cm-) thick red maple LVL billets, and 2. to examine the relationship between nondestructive parameters of red maple veneer and flexural properties of LVL billets.

This chapter describes the joint efforts of the Forest Service and the FHWA to administer national programs including research, demonstration bridges, and technology transfer components. Summary information on a number of Forest Service-WIT demonstration bridges constructed with hardwoods is also provided.

Nondestructive evaluation (NDE) of wood materials has a long history of application in the wood products industry. Visual grading of lumber is perhaps one of the earliest NDE forms. Visual assessment of a piece of lumber requires the grader to estimate a strength ratio on the basis of observed external defects (USDA 1999). The ratio is used to estimate the strength of lumber relative to a similar piece without defects. The estimation is based on standard lumber grading rules; however, it is entirely subjective and governed by the judgment of the grader. Furthermore, the value assigned to...