Treesearch

The production of industrial wood from natural forests is predicted to decline in the future. Factors that will contribute to this decline include changes in land use patterns, depletion of resources in some parts of the world, and the withdrawal of forest areas from industrial production in order to provide for environmental, recreational, and other social needs. There is a shortage of information on the suitability of fiber from many plantation-grown species for alternative composite products. This research was conducted to determine the suitability of plantation-grown Eucalyptus saligna...

Mildew resistance, water repellency, and overall finish appearance were evaluated for 32 deck finishes on western redcedar (Thuja plicata D. Donn.) and Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) after 12, 21, and 39 months of outdoor exposure in western Oregon. The finishes were either solvent-borne or waterborne; were ei- ther clear, tinted, or lightly pigmented; and were, in general, formulated to penetrate the wood surface. Mildew resistance was generally good for most of the finishes through the 21-month evaluation. Water repellency was fair at the 12-month evaluation, but in...

Dowel bearing strength (embedment strength) is a critical component of wood connection design. Previous tests have concentrated on defining the relationship between dowel-bearing strength, specific gravity, and fastener characteristics such as diameter. However, because adoption of yield theory in defining connection strength is relatively new in the United States, few studies have been conducted that completely define the factors influencing dowel-bearing strength. One such factor is moisture content. In this study, the dowel-bearing strength of two groups of specimens was determined. One...

A practical method for tracking the effect of curtailment announcements on lumber supply is described and tested. Combining announcements of closures and curtailments with mill capacities enables the creation of accurate forward-looking assessments of lumber supply 1 to 2 months into the future. For three American and Canadian lumber- producing regions, the method produced projections of supply that were within 0.5 percent accuracy for a 7-month period encompassing June to December 2000. Announcements of production intentions are an important piece of market intelligence that can help...

Published information on estimated air-drying times of lumber is of limited usefulness because it is restricted to a specific location or to the time of year the lumber is stacked for drying. At best, these estimates give a wide range of possible times over a broad range of possible locations and stacking dates. In this paper, we describe a method for estimating air-drying times for specific locations by optimizing a drying simulation using existing experimental air-drying times for northern red oak, sugar maple, American beech, yellow-poplar, ponderosa pine, and Douglas-fir. The results...

The relationship between longitudinal stress wave transit time and wood moisture content (MC) was examined as a potential means of estimating MC control points in dry kiln schedules for lumber. A linear relationship was found between the relative transit time and the average MC of sugar maple and ponderosa pine boards dried according to typical kiln schedules.

The primary objective of this study was to investigate the usefulness of a stress wave technique for evaluating wood strength and stiffness of young-growth western hemlock and Sitka spruce in standing trees. A secondary objective was to determine if the effects of silvicultural practices on wood quality can be identified using this technique. Stress wave measurements were conducted on 168 young growth western hemlock and Sitka spruce trees. After in situ measurements, a 0.61-m-long bole section in the test span was taken from 56 felled trees to obtain small, clear wood specimens. Stress...

Ten tropical hardwoods from Bolivia were evaluated for weathering performance (erosion rate, dimensional stability, warping, surface checking, and splitting). The wood species were Amburana cearensis (roble), Anadenanthera macrocarpa (curupau), Aspidosperma cylindrocarpon (jichituriqui), Astronium urundeuva (cuchi), Caesalpinia cf. pluviosa (momoqui), Diplotropis purpurea (sucupira), Guibourtia chodatiana (sirari), Phyllostylon rhamnoides (cuta), Schinopsis cf. quebracho-colorado (soto), and Tabebuia spp. (lapacho group) (tajibo or ipe). Eucalyptus marginata (jarrah) from Australia and...

In this study, we develop models for predicting loss in bending strength of clear, straight-grained pine from changes in chemical composition. Although significant work needs to be done before truly universal predictive models are developed, a quantitative fundamental relationship between changes in chemical composition and strength loss for pine was demonstrated. In particular, this study explored a linear independent-component modeling approach. The models were evaluated across a range of environmental exposure conditions known to cause strength loss and with several chemical treatments...

This is the first in a series of reports on the erosion rates of wood exposed outdoors near Madison, Wisconsin. The specimens were oriented vertically, facing south; erosion was measured annually for the first several years and biannually for the remainder of the exposure. In the work reported here, the erosion rates of earlywood and latewood were determined for smooth-planed vertical-grained lumber and abrasive-planed and saw-textured flat-grained plywood for an exposure period of 16 years. Lumber species were southern pine, western redcedar, Douglas-fir, and redwood; plywood species were...