Treesearch

The irradiance plotted as function of time to ignition for wood materials tested in the Cone Calorimeter (ASTM E1354) differs signiticantly from that tested in the Lateral Ignition and Flame spread Test (LIFT) apparatus (ASTM E1321). This difference in piloted ignitabilty is primarily due to the difference in forced convective cooling of the specimen tested in both apparatus. By calibrating for the convective heat transfer coefficient and using appropriate heat conduction analysis of the test data for both apparatus, similar values were derived for the following thermophysical properties:...

The Colville Study was developed in 1994 to identify and evaluate a series of management options for achieving ecosystem objectives in dense stands of small-diameter trees while also producing wood products. The Colville National Forest selected the Rocky II Timber Sale as an example of this type of stand that needed management to achieve the following goals: (1) create late successional forest structure, (2) decrease forest health risk from fire, insects, and disease, (3) improve wildlife habitat by providing large green trees and snags, and (4) improve stand aesthetics by decreasing...

In the past decade, bridge railing design criteria have moved away from static-load design and have focused on full-scale crash testing as a more appropriate and reliable means of evaluating bridge railings. The five bridge railing plans presented reflect the results of a cooperative research project between the Midwest Roadside Safety Facility, University of Nebraska--Lincoln; the USDA Forest Service, Forest Products Laboratory; and the Federal Highway Administration. The project objective was to develop and crash test bridge railings and approach railing transitions for longitudinal wood...

A system was developed for grouping tropical wood species for kiln drying based on similar estimated drying times. Six tropical species were subjected to drying and water soaking tests; variables were test temperature and specimen thickness. Soaking time, specimen thickness, and test temperature were used in an empirical model to predict drying times. The capability of the model to predict drying times was considered acceptable based on an adjusted coefficient of determination equal to 0.929 and an average error of 14 percent. The overall capability of the method proposed for grouping...

In recent years biological control has received increasing attention as a means of protecting wooden structures against decay fungi. This has been due, in large part, to increased public awareness and concern over the environment impact of currently used chemical wood preservatives. Laboratory studies have indicated that Trichoderma isolates are able to antagonise wood decay fungi by a number of different mechanisms. These include passive antagonism through competition for available nutrients; active antagonism through the production of soluble metabolites and volatiles and mycoparasitism...

Wood preservation based on in situ polymerization of potentially bioactive monomers has been studied. Tributyltin oxide acrylate (TBTOA) and pentachlorophenol acrylate PCPA) were synthesized. Wood samples were treated at 2%, 5%, 10%, 15% and 20% by weight solutions with varying amounts of either crosslinker (trimethylolpropane trimethacrylate, TMPTM) or methyl methacrylate (MMA) and polymerized in situ in wood samples. Soil block testing was performed on acetone leached samples using Gloeophyllum trabeum in a standard ASTM test for 12 weeks. TBTOA was effective at all levels except when...

Following damage caused by Hurricane Hugo (September 1989) we monitored inorga­nic nitrogen availability in soil twice in 1990, leaf area index in 1991 and 1993, and litter production from 1990 through 1992 in subtropical wet forest of eastem Puerto Rico. Experimental removal of litter and woody debris generated by the hurricane (plus any standing stocks present before the hurricane) increased soil nitrogen availability and above-ground productivity by as much as 40% compared to unmanipulated contro! plots. These increases were similar to those created by quarterly fertilization with...

Laccase is one of the ligninolytic enzymes found in liquid cultures of the fungus Ceriporiopsis subvermispora in defined medium. As an approach to a clarification of the role of laccases during the attack on lignin by the fungus, the enzyme has been characterized further. The levels of this phenol oxidase increase 2-fold in the presence of p-anisidine and are severely affected when addition of either Mn(II) or Cu(II) ions to the medium is omitted. Isoelectrofocusing allowed the resolution of two laccase isoenzymes, with pIS of 3.65 and 3.59. In rich medium, laccase activity is 10-fold...

Moisture accumulation and extreme fluctuations in moisture levels can adversely affect the service life of components, such as wood siding and windows. Adverse moisture conditions can induce checking, warping, paint failure, and in severe cases, rotting of the wood.