Treesearch

Microwave-assisted liquefaction has shown potential for rapid thermal processing of lignocellulosic biomass. The efficiency of microwave heating depends largely on the dielectric properties of the materials being heated. The objective of this study was to investigate the dynamic interactions between microwave energy and the reaction system during the liquefaction of a woody biomass sample. The dielectric properties of poplar wood particles, model compounds representing the three main chemical components of wood, and individual liquefaction solvent components, along with their mixtures,...

Large numbers of migratory bats are killed every year at wind energy facilities. However, population-level impacts are unknown as we lack basic demographic information about these species. We investigated whether fatalities at wind turbines could impact population viability of migratory bats, focusing on the hoary bat (Lasiurus cinereus), the species most frequently killed by turbines in North America. Using expert elicitation and population projection models, we show that mortality from wind turbines may drastically reduce population size and increase the risk of extinction. For example,...

Commercial thinning in hardwood stands is generally applied to reduce overcrowding and to favor the development of desired residual species until the stand is mature. In mixed hardwood stands, commercial thinning also provides an opportunity to promote vigorous overstory oaks (Quercus spp.) that will serve as sources of acorns and advanced seedlings needed to regenerate oaks in the next stand. Forest managers need information on sustaining and increasing the number of overstory oaks at mid-rotation when the stand is still several decades from maturity. In this study, crown class dynamics...

Throughout the deciduous forests of the eastern United States, oak (Quercus) regeneration has declined in stands historically dominated by oak species. In the Wisconsin Driftless Area, the level of decline in oak regeneration is variable and influenced by stand structural development, historical disturbance regime, abiotic site characteristics, and historical land-use legacies. This research aims to elucidate the relative importance and site-specific nature of the factors influencing oak regeneration and identify interactions between drivers. To document stand succession, development, and...

Stocking diagrams come in two forms, the Gingrich diagram and the density management diagram. While they both present the same information about a forest stand, they each provide a different perspective on the data being displayed. Density management diagrams have been around since the 1930s and the Gingrich diagram has been around since the 1960s, but applications of the diagrams to investigate long-term forest dynamics have been rare. We apply both types of stocking diagrams to stands at the Missouri Ozark Forest Ecosystem Project to examine change over a 20-year period and to graphically...

Two plantings of second (BC3F2) and third (BC3F3) backcross generations of hybrid American chestnuts established in east-central West Virginia were assessed after 4 years to determine family effects on growth and survival. Pure American and pure Chinese chestnut seedlings were also planted as controls for height growth, form, blight occurrence, and blight resistance. Overall mortality after four growing seasons totaled 12 percent and 41 percent on the two sites. In 2014, the mean height of live stems differed by site and by seedling type. Pure American and BC3F3 hybrids were the tallest on...

A new syndrome was named rapid white oak mortality in 2011 to describe the rapid death of white oak trees (Quercus alba L.) within one growing season. A survey with 24 questions about stand and site characteristics, site history, and symptoms was distributed to forestry professionals to gather information about the new syndrome. Sixty-three reports were received. Most of the mortality was reported in the southeastern quadrant of Missouri. Site characteristics and the affected trees species were atypical of those usually associated with oak mortality in Missouri. The survey confirmed that...

Oakville is an urban municipality with 846 ha of woodland. Management priorities are to maintain forest health, environmental health, and safety; wood production is a minor objective. The town developed a comprehensive strategy to plan for emerald ash borer (EAB; Agrilus planipennis) induced ash mortality and forest restoration. Oakville has begun implementing its forest management program focusing on removing and salvaging dead and dying ash from its woodlands and supporting forest regeneration. This management plan is described in this paper along with some of the challenges of its...

We quantified species composition, stand structure, canopy disturbance history, and Quercus establishment and canopy accession patterns in an upland hardwood forest in Tennessee. The forest established in the mid-1800s and exhibited structural characteristics that were within the range of what has been reported from other late-successional forests in the region. The forest overstory was dominated by Quercus prinus, but Acer saccharum was the most abundant species. Quercus recruitment was continuous from stand initiation through the 1950s. Prior to 1880, the majority of Quercus trees...

Promoting stand structural complexity is an increasingly popular silvicultural objective, as complex structures are hypothesized to be more resistant and resilient to perturbations. On April 20, 2011 in Lawrence County, Alabama, an EF1 tornado tracked 5 km, leaving a patchwork mosaic of disturbed areas. In summer 2014, we established a 100 m × 200 m (2 ha) rectangular plot perpendicular to the swath of the storm within an affected Quercus alba stand to document the effects of wind disturbance on stand structure. Stem mortality was clustered near the swath of the tornado. Within the 2 ha...