Dimensional stability and decay resistance of clay treated, furfurylated, and clay-reinforced furfurylated poplar wood

Plantation-grown poplar (Populus cathayana) is regarded as a source of low-quality wood, with poor dimensional stability and low decay resistance. In this study, poplar wood was impregnated with sodium montmorillonite (Na-MMT) or organo-montmorillonite (O-MMT), furfuryl alcohol (FA, at concentrations of 15%, 30% and 50%), separately or in their combinations to prepare clay treated, furfurylated, and clay-reinforced furfurylated wood, respectively. The two-step method by introducing Na-MMT first and then FA and organic modifier was feasible to achieve a reasonable penetration. These components could entirely enter the wood cell lumen or partly enter the wood cell wall, and thus initiate a series of reactions. Compared with Na-MMT reinforced furfurylated wood (M-F), the O-MMT reinforced furfurylated wood (O-F) exhibited better dimensional stability (ASE up to 71%) and decay resistance (3.2% mass loss). Moreover, O-MMT played a predominant role in decay resistance of O-MMT reinforced furfurylated wood. Even at low O-MMT loadings, the modified wood had a significant inhibitory effect on the white-rot decay fungus Trametes versicolor. Based on an overall evaluation, O-MMT reinforced furfurylated wood seemed to provide an optimal choice for both moist or wet conditions.

Armillaria limonea.

Armillaria limonea is a white rot wood decay fungus and root disease pathogen that has confirmed presence in New Zealand only, where it is presumed to be indigenous. It is closely related to A. luteobubalina in Australia and South America, and to South American A. montagnei. A. limonea occurs naturally on woody debris and as a cause of butt rot in living trees in podocarp-hardwood and southern beech (Nothofagus) forests where it contributes beneficially to carbon and nutrient recycling. It fruits prolifically in native forests, forming large clusters of "toadstool" fruitbodies during winter. Like many other Armillaria species it is recognized by characteristic white mycelial fans or ribbons produced beneath host bark, and by its bootlace-like rhizomorphs by which it spreads vegetatively from colonized buried woody material or stump root systems to infect living host plants.

Properties of Aging Pentachlorophenol-Treated Douglas-Fir Crossarms

Wooden crossarms play a major role in supporting electric distribution lines in North America, but relatively few data exist on their condition as they age. The residual capacity of Douglas-fir crossarms in service in western Oregon for 45 to 60 years was investigated. Arms were sampled for residual preservative retention, the presence of visible decay fungi, and residual flexural properties; these results were then compared with three nondestructive tools. A majority of the arms tested had preservative levels well below those required for new arms, but only one decay fungus was isolated, and only five arms removed and dissected had any evidence of visible internal decay. Moduli of rupture for the arms were generally below the minimum levels required by national standards, but most still retained at least 67 percent of this value. Nondestructive evaluation tools were generally poorly correlated with flexural properties, possibly because of the heavily weathered and checked exterior condition.