Treesearch

In many forests across the United States, the high forest fuel loadings are contributing to our recent forest fire problems. Many fire-prone timber stands are generally far from traditional timber markets or the timber is not economically valuable enough to cover the costs of removal. To help address this problem, the USDA Forest Products Laboratory has developed a process to produce three-dimensional structural fiberboard products that can utilize the wide range of lignocellulosic fibers contained in the forest undergrowth, underutilized timber, and agro-biomass. In this way, removing...

The effect of temperature on properties can be separated into reversible and permanent effects. The National Design Specification (NDS) provides factors (Ct) for reducing properties for reversible effects but provides little guidance on permanent effects. The primary objective of this paper is to evaluate the effect of prolonged heating (permanent effect) on the flexural properties of solid-sawn and composite lumber products exposed at 66°C and 75% relative humidity (RH) and at 82°C and 30% RH. A second objective is to determine how to estimate total effects. Solid-sawn lumber, laminated...

Early detection of wood decay is critical because decay fungi can cause rapid structural failure. The objective of this study was to compare the sensitivity of different methods purported to detect brown-rot decay in the early stages of development. The immunodiagnostic wood decay (IWD)test, soil block test/cake pan test, mechanical property tests, and chemical analysis were evaluated in southern yellow pine blocks and stakes exposed to Postia placenta for 5 weeks. The IWD test was 100 percent positive in blocks after 5 days of incubation; similarly, IWD was 100 percent positive in stakes...

Medium density fiberboard (MDF) production worldwide is increasing due to the development of new manufacturing technologies. As a result, MDF products are increasingly utilized in traditional wood applications that require fungal and insect resistance. This study evaluated the ability of white and brown rot fungi and termites to decompose MDF consisting of different wood species by measuring weight loss. Furnish in the boards was prepared from heart and sapwood portions of pine (Pinus nigra Arnold var. pallasiana), beech (Fugus orientalis Lipsky), and European oak (Quercus robur L.)...

The proposed method of modelling orthotropic solids that have a nonlinear constitutive material relationship affords several advantages. The first advantage is the application of a simple bilinear stress-strain curve to represent the material response on two orthogonal axes as well as in shear, even for markedly nonlinear materials. The second advantage is that this method correlates yield strengths in the orthogonal directions, which is necessitated by some finite-element programs. Herein, we provide an algorithm for fitting bilinear stress versus strain curves to data, such that the...

Phellinus coronadensis is characterized and described morphologically as a new species from southern Arizona, USA. This fungus was previously reported as P. torulosus based on morphological similarities of the basidiomes and type of wood decay. However, P. coronadensis is restricted to two mountain ranges in southern Arizona and found almost exclusively on living southwestern white pine (Pinus strobiformis). Phellinus torulosus is found primarily in Europe and parts of Asia and is primarily associated with hardwood hosts. Based on sequence analysis of small subunit mitochondria1 ribosomal...

Lignin degradation by the white rot basidiomycete Phanerochaete chrysosporium involves various extracellular oxidative enzymes, including lignin peroxidase, manganese peroxidase, and a peroxide-generating enzyme, glyoxal oxidase. Recent studies have suggested that laccases also may be produced by this fungus, but these conclusions have been controversial. We identified four sequences related to laccases and ferroxidases (Fet3) in a search of the publicly available P. chrysosporium database. One gene, designated mco1, has a typical eukaryotic secretion signal and is transcribed in defined...

In this research we experimented with a new and rapid way of analyzing wood. Near Infrared (NIR)spectroscopy together with multivariate analysis is becoming a widely used technique in the field of forest products especially for property determination and is already firmly established in the pulp and paper industry. This method is ideal for the chemical analysis of wood, and therefore preservative-treated wood. Several commercially treated deckboards were obtained for this study: CCA/Hem-Fir; CCA/Eastern Hemlock; ACZA/Douglas Fir and ACQA-Hem-Fir. They were milled and scanned with a NIR...

In this paper we introduce a new technology based on a mild chemical pretreatment process prior to mechanical pulping. Chips are treated with a dilute solution of oxalic acid (OA) for only 10 minute at 130°C, in a typical example. The properties of the pulp produced by this OA process are quite different from those obtained via conventional chemical pretreatments, providing a much more valuable pulp, and at higher yields. Refining results obtained at the Andritz Pilot Plant in Springfield, Ohio show an outstanding combination of strength improvements, energy savings, and shive and triglycer...

The biopulping process for treating wood chips prior to mechanical pulping has been scaled up through an extensive development program and has been demonstrated at 50 ton semicommercial scale. Detailed engineering analyses and design studies have been performed for full production-scale mill implementation, and the technology is ready for commercial use. This paper will summarize the 50 ton pilot scale equipment constructed to allow in- mill evaluation tests, and design studies for commercial scale implementation of biomechanical pulping. Economic evaluation of the process will be presented...