Treesearch

Michigan Technological University's (Michigan Tech) School of Forest Resources and Environmental Science maintains a log cabin on the north branch of the Otter River in southern Houghton County (Portage Township), Michigan. The cabin was built in 1934-1935 and measures 150 m2. The cabin's location is less than 10 m from the river, and when combined with the region's high snowfall (5+ m per year) and subsequent spring melting, is highly susceptible to occasional flooding and subsequent water damage and decay.

Polyhydroxybutyrate (PHB) was grafted onto cellulose fiber by dicumyl peroxide (DCP) radical initiation via in situ reactive extrusion. The yield of the grafted (cellulose-g-PHB) copolymer was recorded and grafting efficiency was found to be dependent on the reaction time and DCP concentration. The grafting mechanism was investigated by electron spin resonance (ESR) analysis and showed the presence of radicals produced by DCP radical initiation. The grafted copolymer structure was determined by nuclear magnetic resonance (NMR) spectroscopy. Scanning electronic microscopy (SEM) showed that...

Diffusion of chemicals and ions through the wood cell wall plays an important role in wood damage mechanisms. In the present work, free diffusion of ions through wood secondary walls and middle lamellae has been investigated as a function of moisture content (MC) and anatomical direction. Various ions (K, Cl, Zn, Cu) were injected into selected regions of 2 ìm thick wood sections with a microinjector and then the ion distribution was mapped by means of X-ray fluorescence microscopy with submicron spatial resolution. The MC of the wood was controlled in situ by means of climatic chamber...

Freeze-dried cellulose nanocrystals (CNCs) were dispersed in the thermoplastic polyurethane [Pellethane 2363-55D (P55D)] by a solvent casting method to fabricate CNC-reinforced nanocomposites. This study demonstrated that the addition of small amounts (1–5 wt %) of CNCs to P55D increased the thermal degradation temperature while maintaining a similar stiffness, strength, and elongation of the neat P55D. CNC additions to P55D did not alter the glass-transition temperature, but the onset decomposition temperature was shifted from 286 to 327C when 1 wt % CNCs was dispersed in the matrix. The...

This paper summarizes a cooperative project to assess the current condition and life expectancy of 132 timber highway bridge superstructures at locations throughout the United States. Several superstructure types were included in this comprehensive effort, of which two-thirds were sawn timber stringer systems. In-depth inspections were conducted by the project team using visual, probing, and nondestructive evaluation (NDE) techniques to characterize the condition of the primary bridge superstructure components. The condition of the bridges was satisfactory and better for large percentages...

The first life cycle impact assessment for redwood (Sequoia sempervirens) forest management activities (i.e. a cradle-to-sawmill gate input) including the growing, harvesting, and hauling of redwood sawlogs to a sawmill was completed. In the stump-to-truck timber harvesting analysis, primary transport activities such as skidding and yarding consumed the largest amount of fuel and consequently generated the greatest environmental impacts (50% of the total) compared with the other harvesting stages (felling, processing, and loading). Hauling sawlogs to the sawmill was also a major contributor...

Mixed office paper (MOP) pulp without deinking with an ash content of 18.1 ± 1.5% was used as raw material to produce nanofiller-paper. The MOP pulp with filler was mechanically fibrillated using a laboratory stone grinder. Scanning electron microscope imaging revealed that the ground filler particles were wrapped by cellulose nanofibrils (CNFs), which substantially improved the incorporation of filler into the CNF matrix. Sheets made of this CNF matrix were densified due to improved bonding. Specific tensile strength and modulus of the nanofiller-paper with 60-min grinding reached 48.4...

Documenting the environmental performance of building products is becoming increasingly common. Developing environmental product declarations (EPDs) based on life-cycle assessment (LCA) data is one way to provide scientific documentation. Many U.S. structural wood products have LCA-based “eco-labels” using the ISO standard. However, the standard requires underlying life-cycle inventory (LCI) data to be of recent age. This study updates the gate-to-gate manufacturing LCI data for laminated veneer lumber (LVL) for Pacific Northwestern (PNW) and for southeastern (SE) United States. Modeling...

Forest residue is one of the most cost-effective feedstock for biofuel production. It has relatively high bulk density and can be harvested year round, advantageous for reducing transportation cost and eliminating onsite storage. However, forest residues, especially those from softwood species, are highly recalcitrant to biochemical conversion. A severe pretreatment for removing this recalcitrance can result in increased sugar degradation to inhibitors and hence cause difficulties in fermentation at high solid loadings. Here, we presented high titer ethanol production from Douglas-fir...

Developing renewable energy sources with low environmental impacts is becoming increasingly important as concerns about consuming fossil fuel sources grow. Cultivating, harvesting, drying, and densifying raw biomass feedstocks into pellets for easy handling and transport is one step forward in this endeavor. However, the corresponding environmental performances must be quantified. This study presents cradle-to-gate life cycle inventory and impact assessment data for switchgrass fuel pellets potentially manufactured in the US Southeast. Because there are no current manufacturers of switchgra...