Treesearch

This paper describes the current state of the U.S. economy and provides general and statistical information on forest products markets in terms of production, trade, consumption, and prices. Market developments are described for sawn softwood, sawn hardwood, softwood log trade, wood-based panels, paper and paperboard, fuelwood, forest product prices, and housing starts. Policy initiatives that can affect domestic markets and international trade in wood products are also discussed in some detail. Data are provided through the end of the year 2009 with estimates for 2010 and forecasts for 2011.

The lack of data about employment in a number of categories indicates that we do not have full understanding of employment associated with forestry. But for some categories, employment has been declining--especially for wood furniture manufacturing, and to a lesser degree for the pulp and paper industries. This is due in part to lower competitiveness with respect to production and import of products from other countries. There has been a decline in jobs in the U.S. Department of Agriculture, Forest Service, but jobs in state forestry agencies are steady to increasing. Increasing participati...

For a variety of reasons, wood-plastic composite (WPC) products are widely available for some building applications. In applications such as outdoor decking, WPCs have gained a significant share of the market. As an option to improve the efficient use of wood fiber, the USDA Forest Service, Forest Products Laboratory (FPL), has an extensive research program on WPCs. Although often ignored in discussions of WPCs, the flammability of WPCs can be a significant factor in certain building applications. This paper reviews past, present, and planned cooperative FPL research projects on fire-retard...

The main goal of the present paper is to demonstrate the value of design optimization beyond its use for structural shape determination in the realm of the constitutive characterization of anisotropic material systems such as polymer matrix composites with or without damage. The approaches discussed are based on the availability of massive experimental data representing the excitation and response behavior of specimens tested by automated mechatronic material testing systems capable of applying multiaxial loading. Material constitutive characterization is achieved by minimizing the...

This paper outlines a 5-year research plan for the development of a structural health monitoring system for timber bridges. A series of studies identify and evaluate various sensing technologies for measurement of structural adequacy and/or deterioration parameters. The overall goal is to develop a turn-key system to analyze, monitor, and report on the performance and condition of timber bridges. The introduction of structural health monitoring technologies for timber bridges should result in improved safety, longer service life, and improved load ratings.

During maintenance of ancient timber architectures, it is important to determine mechanical properties of the wood component materials non-destructively and effectively, so that degraded members may be replaced or repaired to avoid structural failure. Experimental materials are four larch (Larix principis-rupprechtii Mayr.) components, which were taken down from the drum-tower of Zhengjue Temple of Yuanmingyuan (Old Summer Palace), Beijing, China. The larch components were cut into standard specimens first, and then stress wave transmission times, resistograph and densities were tested....

This paper describes both the field evaluation and laboratory testing of two timber-column-bent bridge substructures. These substructures served as intermediate pier supports for the East Deer Park Drive Bridge located in Gaithersburg, Maryland. A field evaluation of the bridge substructure was conducted in September 2008. Nondestructive testing was performed with a moisture meter, a stress-wave timer, and a resistance micro-drilling tool. In addition, several core samples were removed for further laboratory evaluation. Live load testing of the bridge superstructure, which consists of...

The objective of this study was to investigate how a stress wave travels in a standing tree as it is introduced into the tree trunk through a mechanical impact. A series of stress wave time-of-flight (TOF) data were obtained from three freshly-cut red pine (Pinus resinosa Ait.) logs by means of a two-probe stress wave timer. Two-dimensional (2D) and three-dimensional (3D) stress wave contour maps were constructed based on the experimental data using a commercial software. These stress wave contour maps represent the wave fronts in a time sequence, illustrating the flow of stress wave...

Radial increases in wood specific gravity have been shown to characterize early successional trees from tropical forests. Here, we develop and apply a novel method to test whether radial increases are determined by tree age or tree size. The method compares the slopes of specific gravity changes across a short radius and a long radius of trees with eccentric trunks. If radial changes are determined by size, then the slope of the change should be the same on both radii. If radial changes are determined by age, then the slope should be greater on the short radius. For 30 trees from 12...

The objective of this paper is to determine the kiln conditions necessary to avoid interior enzymatic oxidative discoloration in soft maple. Three drying chambers were designed and constructed to control temperature and relative humidity of maple test samples. The tests showed that drying as soon as possible after harvest at temperatures below 42°C will greatly reduce drying discoloration in soft maple.