Treesearch

In the Pacific Northwest, clearcutting is the preferred method for harvesting wood products from Douglas-fir plantations because it’s economical and mimics a large-scale disturbance. Following a clearcut, Douglas-fir seedlings are planted throughout the recovering native plant community. Yet the newly planted seedlings and native plants aren’t the only vegetation claiming the open ground. Invasive plant species, such as Scotch broom and sweet vernalgrass, can also colonize the site and compete with the seedlings for water, nutrients, and light.Eradicating Scotch broom requires repeated...

Microstickies present a formidable challenge for papermakers. Many strategies have been explored to control them. Enzyme treatment is a promising technology, but the mechanism of its action has not been determined, thus inhibiting further application of this new technology. This study investigated characteristics and size distributions of microstickies treated by esterase-cellulase mixtures. Determination of particle size and number was accomplished using a modified flow cytometer, which combined streaming capillary flow, laser-based particle size analysis and fluorescent dye tracing. The...

In this study, 145 poplar (Populus × euramericana cv.’74/76’) seedlings, a common plantation tree species in China, were selected and their ultrasonic velocities were measured at four timepoints during the frst growth year. After that, 60 poplar seedlings were randomly selected and cut down to determine their acoustic velocity, using the acoustic resonance method. The effects of infuencing factors such as wood green density, microfbril angle, growth days, and root-collar diameter on acoustic speed in seedlings and the relationship between ultrasonic speed and acoustic resonance speed were...

Soy protein isolate (SPI) and insoluble soy four polymeric carbohydrates have been reacted with sodium periodate for the specifc oxidation of vicinal –OH groups to investigate the reactions involved in this approach to soy four adhesives. The reactions have been shown to generate carbohydrate oligomer fractions presenting one, two or multiple aldehyde groups. With the exception of the small molecular weight heptanedial, the smaller molecular weight aldehydes generated from mono- and disaccharides by the same reaction do not appear to form from the insoluble soy four carbohydrates, or have...

The net transport of nutrients by migratory fish from oceans to inland spawning areas has decreased due to population declines and migration barriers. Restoration of nutrients to increasingly oligotrophic upland streams (that were historically salmon spawning areas) have shown short‐term benefits for juvenile salmon, but the longer term consequences are little known. Here we simulated the deposition of a small number of adult Atlantic salmon Salmo salarcarcasses at the end of the spawning period in five Scottish upland streams (‘high parental nutrient’ treatment), while leaving five...

Laurel wilt is a destructive disease of redbay (Persea borbonia) and other species in the laurel family (Lauraceae). It is caused by Raffaelea lauricola, a fungal symbiont of the redbay ambrosia beetle, Xyleborus glabratus (Coleoptera: Curculionidae), cointroduced into the United States around 2002. During assessments of fungi associated with bark beetles from loblolly pine, an unknown fungus was isolated that appeared to have broad-spectrum antifungal activities. In this study, we identified the unknown fungus and determined the inhibitory effect of its secondary metabolites on R....

Environmental drivers of population vital rates, such as temperature and precipitation, often vary at short time scales, and these fluctuations can have important impacts on population dynamics. However, relationships between survival and environmental conditions are typically modeled at coarse temporal scales, ignoring the role of daily environmental variation in survival. Our goal was to determine the importance of fine-scale temporal variation in survival to population dynamics of stream salmonids. We extended the Cormack–Jolly–Seber model to estimate daily survival rates from seasonal...

Functionalized cellulose particles were studied as a potential reinforcement for an unsaturated polyester resin (UPR) system, a common material for automotive applications of fiber reinforced plastics. A preliminary process for incorporating freeze-dried cellulose nanocrystal (CNC) powder into UPR was developed. Three surface chemistries were explored including sulfonated, methyl(triphenyl) phosphonium (PhCNC), and maleic acid (MCNC). By optical microscopy the filler was seen to be agglomerated within the matrix. Fractography showed that these agglomerates acted as stress concentration...

This paper summarizes the 2012-2017 bark beetle epidemic in the Sierra Nevada and its implications for long-term changes in tree species composition and forest structure. Preliminary plot and landscape-scale data are reviewed, showing higher levels of mortality for pine species and greater impacts in the southern Sierra Nevada compared to the northern portions of the range. The federal government owns approximately three quarters of the forested area impacted by high levels of tree morality, with the remainder of the land controlled by nonindustrial (18%) and industrial (6%) ownerships....

About 50 years ago, scientists and managers collaborated in an effort that would evolve into the Silviculture of Allegheny Hardwoods (SILVAH) system. Stout and Brose (2014) summarize this unusual story. SILVAH includes components that range from inventory methods to training sessions to management prescriptions, all of which were designed from the ground up and driven by the needs of managers working in Allegheny hardwood forests. Today, SILVAH has been expanded to support oak forest types. Decision support systems often summarize expert knowledge and synthesize guidelines; scientists...