Treesearch

Loblolly pine is increasingly grown on intensively managed plantation forests that yield excellent growth; however, lumber cut from these trees often contains a large percentage of juvenile wood which negatively impacts strength and stiffness. Because of changing forest management and mill practices the design values for visually graded southern pine were updated in 2013 to more accurately account for the material properties available in commerce. This study was undertaken to assess the bending strength and stiffness of loblolly pine lumber from intensively managed stands located on the...

Douglas fir is the dominant commercial tree grown in the United States. In this study Douglas fir residue was converted to single cell oils (SCO) using oleaginous yeasts. Monosaccharides were extracted from the woody biomass by pretreating with sulfite and dilute sulfuric acid (SPORL process) and hydrolyzing using commercial cellulases. A new SPORL process that uses pH profiling was compared to the traditional method. Both processes yielded 77 g l-1 concentration of sugars. The SPORL generated sugars were evaluated for conversion to SCO using yeasts Lipomyces tetrasporus and Yarrowia...

The solid substrate and spent liquo robtained after SPORL pretreatment of Douglas fir residues were evaluated as substrates for the production of intracellular microbial lipid by Mortierella isabellina NRRL 1757. The production of lipid was investigated in a batch fermentation using different strategies viz. separate hydrolysis and fermentation,quasi-simultaneous saccharification and fermentation(Q-SSF),and whole slurry (solid substrate and spent liquor)saccharification and fermentation. The maximum lipid yield (0.21 g/gsugar) was obtained with Q-SSF of the solid substrate Nutrients...

Owing to their chemical, physical, and functional characteristics, polysaccharides are considered to be the most versatile natural polymers. As a result, their properties have been exploited in various fields of research in the biomedical, pharmaceutical, cosmetic, food, and agricultural industries. A property of special interest is their ability to form systems or materials with unique physicochemical characteristics, such as hydrogels and micro- and nanoparticles for controlled release of active compounds. In the present study, polysaccharide beads formulated from alginate, cellulose...

Creation and management of early successional forest (ESF) is needed to halt and reverse declines of bird species dependent on pioneering plant species or young forests. ESF-dependent bird species require specific structural forest classes and are sensitive to forest age (a surrogate for forest structure), patch size, proximity to patch edges, and the juxtaposition of forest age classes. To date, ESF conservation plans have relied on spatially inexplicit data, lacking patch and landscape metrics, to set habitat goals and to track habitat trends. In a previous study, we used Landsat time...

Throughout forests of the northern hemisphere, some species of ericaceous shrubs can form persistent understories that interfere with forest regeneration processes. In the Appalachian Mountains of eastern North America, mountain laurel (Kalmia latifolia) may interfere in the regeneration of mixed-oak (Quercus spp.) forests. To verify this possibility, I conducted a dendroecology study from 2001 to 2005 in three mixed-oak stands with mountain laurel thickets to elucidate how and when the thickets originated, developed, and were impacting hardwood seedlings. At all three sites, the oldest...

Understanding the structure-property relationships for proteins as adhesives is complicated due to the complex and changeable colloidal nature of most proteins. An abundant source of protein in many parts of the world is the soybean, but the inexpensive soy flour is only 50% protein with the remainder being an approximately equal split of soluble and insoluble carbohydrates. These carbohydrates have been considered the causeof the poor strength under wet conditions for bonded wood products. However, removal of the soluble and/or insoluble carbohydrates did not lead to dramatic improvement...

With increasing interest in bio-based adhesives, research on proteins has expanded because historically they have been used by both nature and humans as adhesives. A wide variety of proteins have been used as wood adhesives. Ancient Egyptians most likely used collagens tobond veneer to wood furniture, then came casein (milk), blood, fish scales, and soy adhesives, with soybeans and caseins being important for the development of the plywood and glulam industries. Despite many years of research on developing adhesive products, it is not clear how the proteins provide good adhesive strength,...

Woodworkers know that wood is porous in that adhesive flows into lumens for a mechanical interlock (1) and that wood absorbs water, allowing the use of water-borne adhesives. However, the anatomical aspects of wood that lend to its porosity are much more complicated and have a greater influence on adhesive performance than is normallyrealized or discussed. This porosity can have both positive and negative effects on adhesive performance. A greater appreciation of how porosity relates to adhesive performance is important in designing new and improved adhesive formulations.

The effect of timber length on time-of-flight acoustic longitudinal measurements was investigated on the structural timber of four Spanish species: radiata pine (Pinus radiata D. Don), Scots pine (Pinus sylvestris L.), laricio pine (Pinus nigra Arn.), and maritime pine (Pinus pinaster Ait.). Time-of-flight longitudinal measurements were conducted on 120 specimens of dimensions 90 x 140 mm using three commercially available acoustic instruments (Sylvatest Duo, USLab, and Microsecond Timer). Time-of-flight data were initially obtained from the full-length (4 m) specimens, and then from the...