Treesearch

Serpula lacrymans, the dry rot fungus, is considered the most economically important wood decay fungus in certain temperate regions of the world, namely northern Europe, Japan, and Australia. Previously, copper-based wood preservatives were commonly used for pressure treatment of wood for building construction, but some decay fungi are known to be copper tolerant. In this study, soil-block tests were undertaken to clarify the effect of copper, copper citrate, and alkaline copper quaternary-type D (ACQ-D) on the decay capabilities of S. lacrymans compared with an alternative wood preservativ...

Reaction of wood with anhydrides, isocyanates, and epoxides reduces the moisture content of the cell wall and increases the resistance of the modified wood to attack by fungi. As the level of bonded chemical increases. the cell wall equilibrium moisture content decreases and the resistance to attack by white-and brown-rot fungi increases. There is a direct relationship between the decrease in cell wall moisture content and resistance to fungal attack The mechanism of the effectiveness of chemical modification to provide decay resistance seems to be due to the reduction of moisture content...

As of July 2005, the main stream of the softwood lumber industry in the U.S. and Canada consisted of about 1,067sawmills. These sawmills had a combined capacity of 189 million m3 (80 billion BF), employed about 99,000, produced about 172 million m3 (nominal, 73 billion BF) of lumber, and in the process consumed about 280 million m3 of wood.

This paper presents some research results from recent trial studies on measuring acoustic velocities on standing trees of five softwood species. The relationships between tree velocities measured by time of flight method and log velocities measured by resonance method were evaluated. Theoretical and empirical models were developed for adjusting observed tree velocity values to equivalent log velocities.

Red maple (Acer rubrum) is a medium-sized tree 15 to 20 meters (50 to 65 feet) high and 30 to 60 centimeters (12 to 24 inches) in diameter with a generally fairly clear trunk. This species and silver maple (Acer saccharinum) are often called “soft maples” to distinguish them from the higher density sugar and black maples that are commonly referred to as “hard maples”. Other soft maples are boxelder (Acer negundo) and big leaf maple (Acer macrophyllum), but they are not commonly found as commercial items in the Northeast and Lake States. Red maple is characteristic of swampy sites, but it...

To develop service life prediction methods for the study of sealants, a fully instrumented weather station was installed at an outdoor test site near Madison, WI. Temperature, relative humidiy, rainfall, ultraviolet (UV) radiation at 18 wavelengths, and wind speed and direction are being continuously measured and stored. The weather data can be integrated over time to calculate the dose of the weathering factors. In the study reported here, sealant test specimens were installed in a specially designed apparatus that subjected them to weather-induced cyclic movement that forced a response....

The chapter provides information on treatment chemicals, pretreatment specifications, and pertinent standards that help specify wood for covered bridges that will resist biodeterioration.

The testing of sealant samples has been restricted to devices that either focus on fatiguing multiple samples or quantifying the mechanical properties of a single sample. This manuscript describes a device that combines these two instrumental designs: the ability to both fatigue and characterize multiple sealant samples at the same time. This device employs precise movement capability combined with a stiff loading frame and accurate force measurement for the characterization of five ASTM C719 sealant samples. The performance of this device is demonstrated by monitoring the changes in...

The hemicelluloses have not received adequate attention in studies of wood cell walls because the complexity of their structures does not admit easy interpretation within the paradigms of polymer science. Two-phase composite models of the cell wall have led many to view their primary function as one of coupling cellulose and lignin to enhance the mechanical properties of the walls. But that is a microscopic interpretation based on macroscopic theories of reinforced structures. In contrast, recent studies have shown that hemicelluloses can participate in regulation of the nanoscale architect...

Uneven-aged and diameter-limit management were compared with an unmanaged control on the Fernow Experimental Forest near Parsons, West Virginia, to determine how treatment affects the quality of red oak (Quercus rubra L.), sugar maple (Acer saccharum Marsh.), and yellow-poplar (Liriodendron tulipifera L.). Periodic harvests slightly increased stem lean, which often causes tension wood. The grade of red oak was lower under the diameter-limit treatment compared with that of the control, but this was due primarily to tree size; in contrast, uneven-aged management improved red oak grade...