Treesearch

Determing the reproductive phenology of snakes is important since it marks a time period where snakes are particularly vulnerable to predation. In addition, knowledge of reproductive phenology may help captive breeding programs specify appropriate times to pair snakes for reproduction.

A plot-based census was conducted of trees >8.9 cm in breast height diameter in a 4000 ha forest in northeastern California in 1933 and 1934, prior to any harvest activity. The trees were tallied by size class and species on contiguous plots specified to be 1.01 ha in size, although some plots had a forested area less than this specification due to natural openings in the forest. In general, variability in all metrics declined as scale increased across a range from 1 ha to 244 ha, although much of this variability was in the tails; the inner quartile range appeared to be more stable,...

A diverse workforce in science can bring about competitive advantages, innovation, and new knowledge, skills, and experiences for understanding complex problems involving the science and management of natural resources. In particular, fisheries sciences confronts exceptional challenges because of complicated societal-level problems from the overexploitation and degradation of aquatic ecosystems worldwide. Here, we examine the status of gender and race or ethnicity among the US fisheries science workforce on the basis of a survey of 498 faculty members from 56 institutions of higher...

Chemical modification of wood increases decay resistance but the exact mechanisms remain poorly understood. Recently, Ringman and coauthors examined established theories addressing why modified wood has increased decay resistance and concluded that the most probable cause of inhibition and/or delay of initiation of brown-rot decay is lowering the equilibrium moisture content. In another recent study, Jakes and coauthors examined moisture-induced wood damage mechanisms, including decay and fastener corrosion, and observed that these mechanisms require chemical transport through wood cell...

To predict the value of trade between countries, a differential gravity model of bilateral trade flowswas formulated and estimated with panel data from 2005 to 2014 for each of the commodity groups HS44 (wood and articles of wood), HS47 (pulp of wood, fibrous cellulosic material) and HS48 (paper and paperboard). The parameters were estimated with a large database by ordinary least squares, fixed-effects and random-effects methods. For the three commodity groups, the results were stable across methods. For HS44, exports were inelastic (0.33+0.19) with respect to the gross domestic product...

Wood species that exhibit innate tolerance to wood destroying organisms such as termites are considered to be naturally durable. This durability can, in part, be due to the complex chemical compounds in the heartwood of naturally durable wood species. We examined the effects of varying concentrations of heartwood extractives on the subterranean termite, Reticulitermes flavipes from four wood species from Pakistan (Dalbergia sissoo, Cedrus deodara, Morus alba and Pinus roxburghii) as well as Teak (Tectona grandis). Termites showed increasing levels of mortality with increasing concentration...

Natural durable wood species are those which exhibit innate tolerance to wood decay organisms such as fungi and termites. The goal of this study was to evaluate 4 wood species (Dalbergia sissoo, Cedrus deodara, Morus alba and Pinus roxburghii) from Pakistan in order to determine their resistance to both a model brown (Postia placenta) and white (Trametes versicolor) rot fungus compared to a durable reference species (Tectonis grandis). In a 12 week soil bottle test, C. deodara and M. alba were found to be resistant to decay, D. sissoo was moderately resistant and P. roxbughii was non-resist...

Seasonal cambial activity was investigated in one- to three-year-old branch modules (branch constructional units) of ten woody species from cerrado sensu stricto, a savanna-like ecosystem, of southernBrazil. Relationships between cambial activity and environmental factors (precipitation, temperature,day length) and leaf production were tested using generalized linear mixed model. Regardless the planthabit and leaf shedding patterns, cambial activity (about 5 months) corresponded to the core of the rainyseason (when at least 66% of the annual precipitation had been reached), even though...

After exposure in the field and laboratory soil block culture testing, the void content of wood–plastic composite (WPC) decking boards was compared to unexposed samples. A void volume analysis was conducted based on calculations of sample density and from micro-computed tomography (microCT) data. It was found that reference WPC contains voids of different sizes from the micrometer range up to several cubic millimeters. Large voids were unevenly distributed within the composite sample. Void size and volume increased after conditioning the WPC in water at 70°C. Depending on the effect of...

Several nondestructive evaluation (NDE) technologies were studied to determine their efficacy as scanning devices to detect internal moisture and artificial decay pockets. Large bridge-sized test specimens, including sawn timber and glued-laminated timber members, were fabricated with various internal defects. NDE Technologies evaluated in this research were ground penetrating radar (GPR), microwave scanning, ultrasonic pulse velocity, ultrasonic shear wave tomography, and impact echo methods. Each NDE technology was used to evaluate a set of seven test specimens over a 2-day period and...