Abstract

In the United States, modern designs of wood floor systems rarely directly account for annoying floor vibration criteria, because it is not a required design criterion in the International Building Code or the International Residential Code. However, adhesives are sometimes used to supplement traditional subfloor fasteners in an effort to improve the floor vibration performance, but they are mainly used to reduce or eliminate homebuilder “callbacks” due to floor squeaks. This article addresses using high performance deformed shank fasteners rather than adhesives to minimize common annoying floor vibration problems.

Abstract

Western red cedar (WRC; Thuja plicata) is highly valued for its natural durability. Rapid methods to assess heartwood durability are needed to identify breeding stock that will ultimately yield trees with durable wood when harvested. Chromatographic methods to detect heartwood extractives have been developed, but these still require significant time and laboratory resources and rely upon an understanding of the relationship between extractives and durability that is still incomplete. Visible/near-infrared (VIS/NIR) spectroscopy combined with multivariate statistical analysis has been used to rapidly predict a wide range of wood properties, including extractive content and decay resistance. The present work investigates the ability of VIS/NIR spectroscopy to predict extractive content, decay resistance, and termite resistance of WRC heartwood and explores the association between extractive content and durability. Partial least squares (PLS) models based on VIS/NIR spectra had moderate predictive ability for lignans, plicatic acid, beta-thujaplicinol, and total extractives. Other extractives were poorly predicted. Developed PLS models were not predictive for decay resistance but were moderately predictive of termite resistance. Decay and termite resistance were not strongly associated with any measured extractive. A moderately strong correlation was observed between termite resistance and red coloration (a*). Some of the models developed may be suitable for screening, but none are accurate enough for phenotyping.

Abstract

The potential for using pretreatment with cinnamon leaf oil or juniper foliage oil to improve the durability of viscoelastic thermal compression (VTC)–treated hybrid poplar was explored in a field termite test and a laboratory mold test. The addition of oils prior to VTC processing had variable effects on resistance to both mold and termite attack. Subsequent gas chromatography–mass spectroscopy assessment of residual oil components in VTC processed material suggested that the heating associated with the process was associated with substantial degradation of oil components that might help explain the lack of protective effect. The results suggest that further attempts to use essential oils to improve the durability of VTC processed materials must first explore less aggressive heating conditions to reduce the potential for thermal degradation of oil components while still achieving the attractive gains in physical properties associated with the process.

Abstract

Effects of tip height and material type, radial clearance angle, and blade lateral runout of circular saws on the machined surface quality of medium-density fiberboards (MDF) cut by circular saws in terms of roughness height were investigated. Experimental results indicated that the tip material type and magnitude of tip radial clearance angle affected the surface roughness height of MDF the most. Using circular saws brazed with polycrystalline diamond (PCD) tips can significantly reduce the surface roughness height compared with using tungsten carbide tips. Circular saws brazed with PCD tips of a radial clearance angle of 0.5° reduced the surface roughness height by as much as half compared with the one with a radial clearance angle of 1.0°. Analytical analysis results indicated that a circular saw with longer tips of a smaller radial clearance angle should be preferred.

Abstract

Physical and mechanical properties of a range of commercially produced kraft paper honeycomb stock panels were assessed to provide technical information of interest to primary and secondary manufacturers and product end users. Five groups of four replicate panels each 44.45 mm in thickness were fabricated by Panolite Industries, Lac Megantic, Quebec, from unlaminated 6.3- and 9.5-mm-thick medium-density fiberboard (MDF) and particleboard (PB), and 3.2-mm-thick veneered hardboard (HB). At 65 percent relative humidity (RH) sandwiches made from MDF were superior in mechanical properties to those made from PB. Marked differences in flexural properties were found for 3.2-mm veneered HB; this type of facing and the sandwich structure made from it is significantly greater in flexure when the wood veneer runs parallel to the long axis of the panel. For PB and MDF facings, sandwiches were stronger and stiffer if made from thicker facing material (9.5 mm), and there was a small but significant effect of honeycomb ribbon orientation: an orientation parallel to the long axis of the panel/test specimen gives the sandwich greater resistance to deformation under load. Conditioning facing materials and sandwich specimens under 95 percent RH over 45 days caused loss of strength properties of up to 50 percent, especially for 6.3-mm MDF.

Abstract

Dyeing pale-colored plantation-grown hardwood is an effective way to meet the demand for richly colored tropical hardwoods used in decorative applications. The objective of this study was to investigate the influence of wood dyeing parameters such as vacuum pressure, vacuum time, dyeing time, and dye concentration regarding the dyeing of Populus cathayana Rehd using the vacuum dyeing system. As the height increased, the color change decreased gradually. Color change and dye uptake gradually increased with increasing vacuum pressure and dye concentration. As the vacuum time and dyeing time increased, color change and dye uptake first gradually increased until water began to be discharged, leading to a decrease of the pressure gradient in the log, and then decreased.

Abstract

The potential of near-infrared spectroscopy (NIRS) to determine the transition from juvenile to mature wood in black spruce (Picea mariana (Mill.) B.S.P.) was assessed. In total, 127 wood samples were harvested from 50 sites located across the black spruce–moss domain in the province of Québec, Canada. Mechanical wood properties were determined by SilviScan. NIR spectra were collected on the transverse face of the samples. Good to excellent calibration statistics (R ², ratio of performance to deviation) were obtained for basic density (0.85, 1.8), microfibril angle (0.79, 2.2), and modulus of elasticity (0.88, 2.9). Two-segment linear regressions were applied to microfibril angle profiles to determine the transition age and then calculate the juvenile and mature wood properties. The values obtained using SilviScan data were compared with those obtained using NIRS predicted data. Using SilviScan data, the average transition age was 23 years, with a standard deviation of 7 years. The correlation was moderate for the transition age (r = 0.592, P < 0.0001), which was slightly underestimated by NIRS with a mean prediction error (and 95% limits of agreement) of −2.2 ± 6.3 years (−14.6/10.1). These results suggest that the transition age from juvenile to mature wood could be predicted by NIRS. This article makes some recommendations to improve method accuracy for operational use.

Abstract

Technical research projects often target innovative high-value products. These products may serve dynamic and fast-growing markets. However, while the general demand for such products may be very high and a lot of technical research is carried out in developing the respective processes, only very few new technologies and products are commercially realized and placed on the market. In order to widen the market focus toward a more comprehensive understanding of technical development, this study presents a mix of methods, including production cost analysis, business-to-business survey, and market impact assessment. When it comes to exploring a new technology that produces bioactive substances from wood, this article shows how the previously mentioned methods can be adapted, applied, and integrated for its successful commercialization.

Abstract

Forest industries worldwide are facing a range of challenges, such as declining demand for newsprint, fluctuating sawn-wood prices, and society's concern of forestry's negative environmental impacts. On the other hand, the growing interest in bioenergy and renewable products may represent opportunities for the forest sector. Few assessments of the industry's expectations regarding future development of the major external forces driving the forest sector seem to have been carried out. We undertook two participatory surveys of sawn-wood industry managers in Norway in 2010 and 2013, assessing their expectations of how key factors develop until 2020. The respondents expressed beliefs that the demand for sawn-wood and bioenergy will grow and that sawmilling productivity will increase together with international trade. Society's concern for the environment was expected to rise, leading to higher demand for wood products but also more expensive forestry operations. A bioenergy demand increase of 50 percent, very high energy prices, competitive second-generation biofuel, and the first second-generation biofuel plant being established in Norway were perceived to be notably less likely in 2013 than in 2010. The questions were associated with scenarios of the Norwegian forest sector used in quantitative scenario analyses. In the 2013 survey, less support was given to the scenario with high priority on environmental issues and rapid bioenergy deployment. Recent policy and market shifts that imply a lower emphasis on the environment and cheaper fossil fuels may help explain this change. The survey indicates that short-term shifts in policy and economic factors may considerably impact key agents' assumptions about the future.

Abstract

This article investigates the contribution of the Croatian wood industry to the overall Croatian economy. The contribution is analyzed in terms of production, employment, and value added, using the input–output method for analysis. The objective of this article is to calculate multipliers for the wood industry in Croatia and benchmark them to the economies of similar European new member states. The model uses the so-called open model calculation, from which households are excluded. It comprises direct and indirect effects only, without induced effects, which is one of the distinguishing features of the so-called closed model. Results are benchmarked to other national economy sectors and similar transition economies. The wood industry output multiplier is the highest in Croatia and Poland. Domestic producers use various domestic and imported inputs in the production process. Input–output multipliers are calculated for both domestic and foreign demand (exports). Exports are profoundly important for Croatia as a small, open economy. Results of this research are useful to a wide range of policymakers and academics.

Abstract

The propagation velocity of ultrasonic waves from measurements in trees is numerically different from the velocity obtained from measurements in logs, even in freshly felled logs, and the latter velocity is better correlated with the quality of the wood. The differences can be explained by the basic and fundamental aspects of wave propagation; however, these aspects are difficult to consider in practical applications. Thus, the present study examined parameters that are more easily obtained in the field and considered to provide an equivalent log velocity based on living tree velocities. The results indicate that base logs are better correlated with the velocities measured in trees, because the measurement in trees is performed at the stem base. However, the inclusion of the diameter at breast height (DBH) can produce a model with the same prediction accuracy as that of logs obtained from the whole tree. The inclusion of the green density does not improve estimations of the velocity of logs using the velocity obtained for the tree. Considering that DBH is a parameter often used in forest management, this result can be useful for improving the accuracy of wood-quality predictions from acoustic trials in standing forests.

Abstract

Colorado's forests have been decimated by a mountain pine beetle outbreak. The mountain pine beetle introduces a blue-stain fungus into the trees, lowering the economic value of the wood. As a result, forest product manufacturing opportunities using beetle-killed trees are limited. One possibility is to use beetle-killed trees to make cut stock, which is lumber that has been cut into specified length, width, and thickness requirements from a cant, lumber, or glued-up panels. The White River Conservation District commissioned this study to determine if a relationship existed between the amount of time beetle-killed trees remain standing dead and the recovery rate for cut stock material from those trees. Conducted in north-central Colorado and south-central Wyoming, this study found that enough material does exist in beetle-killed lodgepole pine trees to produce cut stock but that a tree's diameter at breast height is a better predictor for the cut stock recovery rate from the logs rather than the time spent standing dead on the stump. Given the increasing likelihood that beetle-killed trees will blow down as time passes, incentives for increased beetle-killed wood utilization should be developed quickly.

Abstract

Although harvester use in recent years has increased in Maine, in the past 25 years no productivity or cycle time information was made available for harvesters operating in Maine's softwood stands. In order to update regional production and cost models it was necessary to develop cycle time equations for harvesters. Time and motion studies of harvesters in thinning operations were conducted during the summer of 2012 at four harvest sites under a variety of stand and site conditions common to central Maine. Results show cycle time differences for harvesters based on stem size as well as hardwood and softwood species groupings. A linear mixed-effects model was developed to explain the influence of stem size and species on processing time. The combination of operator, machine, and site conditions was used as a random effect in this model, which explained 5 percent of data variance. The adjusted R ² for this model was 0.20, and the model was validated using two independent harvester time studies conducted in 2013. Validation results show that the developed model predicts total harvest time within 5 to 25 percent of the observed time. This model will allow for updated logging cost predictions by land managers and logging contractors, but it also clearly shows the effect of stem size on time consumption and subsequently on productivity.

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