Treesearch

The exposure of wood to elevated temperatures during hot water extraction (HWE) has been shown to significantly influence a variety of physical and chemical properties of the wood. Aspen (Populus tremuloides) and hemlock (Tsuga canadensis)strands underwent HWE at 160° C for four different periods of time. The weight loss (WL) associated with the processes ranged from 2.9 to 17.3% for the aspen, and from 2.9 to 12.8% for the hemlock. The higher WL associated with the hardwood was attributed to higher hemicellulose content in the hardwood than in the softwood as well as differences in...

The aim of this work was to investigate the kinetics of multiple chemicals in acid bisulfite pretreatment and the relationship between total sugar yields and pretreatment factors (temperature and time). The results showed Saeman model accurately fitted the pretreatment process. According to this kinetic model, a maximum hemicellulose hydrolysis yield was achieved at a treatment time of 75 min with a temperature of 145° C. Meantime, the concentrations of acetic acid, hydroxymethylfurfural (HMF), and furfural were 1.54, 0.60, and 1.15 g L-1, respectively. Also, a Lorentzian function...

Paenibacillus sp. JDR-2 (Pjdr2) has been studied as a model for development of bacterial biocatalysts for efficient processing of xylans, methylglucuronoxylan, and methylglucuronoarabinoxylan, the predominant hemicellulosic polysaccharides found in dicots and monocots, respectively. Pjdr2 produces a cell-associated GH10 endoxylanase (Xyn10A1) that catalyzes depolymerization of xylans to xylobiose, xylotriose, and methylglucuronoxylotriose with methylglucuronate-linked α-1,2 to the nonreducing terminal xylose. A GH10/GH67 xylan utilization regulon includes genes encoding an extracellular...

Wood processing often involves an array of products and coproducts and a cascade of primary and secondary uses. Prior life-cycle assessment (LCA) reporting allocated environmental burdens to products and coproducts based on mass for multiproduct systems to develop environmental product declarations, which are developed from LCAs following the procedures detailed in product category rules (PCRs). A recent PCR for North American structural and architectural wood products requires allocation by economic value when the main products exceed the value of coproducts by greater than 10 percent....

Wildfire mitigation in Pinyon-Juniper woodlands in the Colorado Plateau region is a management priority. Two wildfire mitigation treatments, mastication and thin-pile-burn, are often chosen based on costs and availability of equipment, yet there are ecological concerns with either treatment. Ecological outcomes from additions of low quality organic residues following mastication can potentially alter microbially mediated soil nitrogen availability, therefore we wished to evaluate the effects of the additions of low quality woody residues to the soil surface compared to thin-pile-burn...

The walnut twig beetle, Pityophthorus juglandis Blackman, and its fungal associate Geosmithia morbida Kolařík et al., produce thousand cankers disease, which has devastated black walnut (Juglans nigra L.) in several states of the western U.S.A. To better understand beetle flight dynamics and life history, flight times were documented in the urban corridor along the Colorado Front Range during 2 years - in 2008 with yellow sticky card traps and in 2012 with baited multiple funnel traps. Walnut twig beetles were determined to be active throughout the trapping season from March through...

Combustion performance for three types of wood–aluminum composites was investigated using cone calorimetry tests. The results revealed that time to ignition of the specimens was increased and more than 100 times after the lamination of 1.6-mm-thick aluminum alloy sheet on the surface (from 17 to 1990 s). And residual mass of the wood–aluminum composites was improved and almost quadrupled (from 21.795% to 81.664%). The peak heat release rate, average heat release rate, total heat release, and mean mass loss rate of wood–aluminum composites with 1.6-mm-thick aluminum alloy sheet on the...

The Forest Products Annual Market Review 2016-2017 provides a comprehensive analysis of markets in the UNECE region and reports on the main market influences outside the UNECE region. It covers the range of products from the forest to the end-user: from roundwood and primary processed products to value-added and housing. Statistics-based chapters analyse the markets for wood raw materials, sawn softwood, sawn hardwood, wood-based panels, paper, paperboard and woodpulp. Other chapters analyse policies, forest products trade barriers affecting the UNECE region, and markets for wood energy....

Trees in cities can contribute significantly to human health and environmental quality. In 2002, there were an estimated 26.9 million trees (36.9 trees / acre) within non-forested urban areas in Wisconsin. In 2012, the non-forest urban areas were reassessed based on 185 field plots. Urban forest attributes changed between 2002 and 2012 due, in part, to the expansion of urban areas, but also tree planting and natural regeneration, tree growth and tree mortality. Based on the 2012 data, urban forest structure, functions, health, and values in non-forest urban areas in Wisconsin (i.e.,...

This article discusses four features of islands that make them places of special importance to environmental conservation. First, investment in island conservation is both urgent and cost-effective. Islands are threatened hotspots of diversity that concentrate unique cultural, biological and geophysical values, and they form the basis of the livelihoods of millions of islanders. Second, islands are paradigmatic places of human–environment relationships. Island livelihoods have a long tradition of existing within spatial, ecological and ultimately social boundaries and are still often...