Wood and fibre properties of fertilized Norway spruce

Very intensive forest management is relatively unexplored in Sweden, and while there is interest in pursuing e.g. the use of fertilizers on selected areas, there is concern about the quality of the wood when growth rate increases. This thesis summarises three studies on wood and fibre properties of Norway spruce grown in two nutrient optimisation experiments and one study from a Norway spruce provenance trial in Sweden. The nutrient optimisation trials were located at 57'08'N, 14'45'E and at 64'07'N, 19'27'E. Increment cores (12 mm diameter) were sampled at breast height from three different treatments and a control. The treatments were irrigation, irrigation combined with liquid fertilization and solid fertilization. Density, microfibril angle, cell wall thickness and radial and tangential cell widths were measured on the wood samples and averages per annual rings and fibre property distributions were analysed. Density, microfibril angle, and cell wall thickness were clearly affected by fertilization. Density and cell wall thickness decreased due to fertilization and microfibril angle increased. Cell widths were moderately affected. Variables describing the inherent development from the pith, such as distance or ring number from pith and ring width, an expression of temporal growth rate and an indicator of varying amounts of earlywood and latewood, were the most important factors explaining differences in fibre properties. The provenance study was situated at 57'56'N, 5'39'E. The differences in density found between provenances were lower than differences caused by fertilization. The possible impact of intense commercial fertilization of Norway spruce for utilization in the pulp and paper industry is discussed

Evaluating selected properties of underutilized hardwood species for fabrication of cross-laminated timber industrial mats

Softwood is more in demand than hardwood because it is used primarily in the US\u27s largest wood-consuming industry, construction, resulting in increased importation of softwood annually to meet this demand. Hardwood, used for non-structural purposes like furniture and interior designs, is more abundant in US forests. However, some hardwood species are underutilized and undervalued. Cross-laminated timber (CLT) has increased the demand for softwood. A study evaluated the mechanical and physical properties of three underutilized hardwood species (321 yellow poplar, 393 sweetgum, and 262 red oak specimens) for CLT industrial mat manufacturing. The results showed that red oak had a higher density than southern yellow pine, and all species had an average modulus of elasticity greater than the CLT lumber requirement. The study confirmed the viability of these underutilized hardwoods for CLT fabrication, suggesting they could be a suitable substitute for softwood in CLT manufacturing

Tailoring fiber properties to paper manufacture: recent developments

"June 1995.""Submitted to TAPPI Pulping Conference, October 1-5, 1995, Chicago, Illinois.

Properties of Veneer and Veneer-Based Products from Genetically Improved White Spruce Plantations

This study examined the suitability of genetically improved fast-growing and short-rotation plantations for veneer-based products. The materials came from a 36-year-old white spruce (Picea glauca) half-sib progeny/provenance trial located in two regions (sites) of Quebec. A total of 270 sample trees were collected for the study, 130 trees from St-Ignace in the Gaspé Region and 140 trees from Valcartier near Quebec City. Veneer from the Valcartier site had a mean wood density of 0.353 g/cm3 and a mean modulus of elasticity (MOE) of 9.48 GPa (1.375 million psi). Veneer from the St-Ignace site had a mean wood density of 0.345 g/cm3] and a mean MOE of 8.05 GPa (1.167 million psi). The differences in veneer wood density and MOE between the two sites were statistically significant. Compared to other Canadian species commonly used for veneer products, the genetically improved fast-growing and short-rotation white spruce yielded considerably lower veneer stiffness.The plantation-grown white spruce veneer from both sites was knotty. Ninety-eight percent of the veneer was classified as visual grade C. The visually graded veneer would be suitable for sheathing grade plywood. With proper stress grading, 14% of the white spruce veneer was suitable for 12.41 GPa (1.8 million psi) grade laminated veneer lumber (LVL), and another 24% of the veneer was suitable for a lower 10.34 GPa (1.5 million psi) grade of LVL, or as core plies for LVL manufacture. The remaining 62% of the stress-graded veneer was suitable for sheathing grade plywood

A Novel Process for the Production of Unidirectional Hybrid Flax/Paper Reinforcement for Eco-composite Materials

AbstractIn this paper a new process to manufacture unidirectional reinforcements for eco-composite materials, made of natural fibers, is presented. Starting with flax rovings of different sizes, an apparatus was developed to feed and align the rovings over the wet-end section of a paper machine. The short kraft paper fibers are therefore mixed with the long flax roving as the machine is running, and at the end of the process, a sheet of the hybrid dry reinforcement is obtained and cut to size for impregnation with various resins, using different processes. This novel manufacturing process allows for high volume production of reinforcement. It is very flexible, and many different combinations of long and short fibers can be exploited for the production of a vast variety of dry reinforcements. In this paper, composite samples are obtained out of these reinforcements, using the resin infusion (RI) molding process with a commercial epoxy resin. The results are compared with those of usual glass fiber reinforcement. An interesting aspect is that the large variability, typical for natural fibers, is largely reduced when the short kraft fibers are present in the composite. In terms of permeability to resin, reasonably comparable values can be obtained compared to that of glass fabrics, if a low surface density of reinforcement is chosen

Forecasting future consumption of coniferous wood in India: a quantitative approach

Over the last few years, Canada has been very successful in increasing its trade in wood products with China. India however, still remains an elusive market. There is a large amount of peer reviewed literature on the specifics of the Indian wood market, and the potential for trade in softwood products. Whereas the majority of studies describe in great detail the opportunities and constraints in dealing with India, very little quantitative information is available about the trends and patterns that determine the Indian wood market. This study uncovered and described one such trend by identifying the relationships between the level of imports of softwood products and such factors as India's Gross Domestic Product (GDP), domestic production, the price of lumber on international markets, tariffs, and the price of Teak logs as a substitute for softwood products. This study analyzed 13 years of quarterly data using the ordinary least square regression technique. Diagnostics were conducted using Akaike and Schwartz criterions, the Durbin-Watson test, and the Breusch-Pagan-Godfrey test for heteroscedasticity. Results suggest that the indicated variable collectively explain 74% of variability in import levels. Two variables in particular, real GDP and the price of Teak have a significant, positive impact on the level of imports of softwood products with 0.45 and 0.49 as respective elasticities. Continuing growth of India's GDP will ensure an ever increasing demand for imported wood products in the years to come. To maximize this opportunity, North American exporters should not compete with New Zealand's low quality pine, but should instead focus on competing with dark coloured tropical hardwoods that are becoming prohibitively expensive as world wide supplies of Teak and other tropical hardwoods continue to diminish. --P. i.The original print copy of this thesis may be available here: http://wizard.unbc.ca/record=b180562

Characterisation and categorisation of the diversity in viscoelastic vibrational properties between 98 wood types

International audienceContext Increased knowledge on diversity in wood properties would have implications both for fundamental research and for promoting a diversification of uses as material. *Aims The objective is to contribute to overcoming the critical lack of data on the diversity of wood dynamic mechanical/viscoelastic vibrational properties, by testing lesser-known species and categorizing sources of variability. *Methods Air-dry axial specific dynamic modulus of elasticity (E'/γ) and damping coefficient (tanδ) were measured on a wide sampling (1792 specimens) of 98 wood types from 79 species. An experimental device and protocol was designed for conducting systematic (i.e. rapid and reproducible) characterizations. *Results Diversity at the specimens' level corroborates the "standard" relationship between tanδ and E'/γ, which is discussed in terms of orientation of wood elements and of chemical composition. Diversity at the species level is expressed on the basis of results for normal heartwood, with specific gravity (γ) ranging from 0.2 to 1.3. Axial E'/γ ranges from 9 to 32 GPa and tanδ from 4×10-3 to 19×10-3. Properties distribution follows a continuum, but with group characteristics. The lowest values of tanδ are only found in certain tropical hardwoods. Results can also suggest alternative species for musical instruments making

Patterning Of Surfaces To Control The Storage, Mobility And Transport Of Liquids For Microfluidic Applications

Systems and methods to pattern surfaces to create regions of variable adhesive force on a superhydrophobic paper surface. By taking advantage of high surface energy sticky islands on a non-sticky superhydrophobic surface, microliter water drops can be registered or confined at specific locations; selected drops can then be transferred to another patterned substrate and the drops mixed and/or allowed to react without the need for pipettes or other fluid transfer tool.Georgia Tech Research Corporatio

Characterisation and categorisation of the diversity in viscoelastic vibrational properties between 98 wood types

Context : Increased knowledge on diversity in wood properties would have implications both for fundamental research and for promoting a diversification of uses as material. Aims : The objective is to contribute to overcoming the critical lack of data on the diversity of wood dynamic mechanical/viscoelastic vibrational properties by testing lesser known species and categorising sources of variability. Methods : Air-dry axial specific dynamic modulus of elasticity (E′/γ) and damping coefficient (tanδ) were measured on a wide sampling (1,792 specimens) of 98 wood types from 79 species. An experimental device and protocol was designed for conducting systematic (i.e. rapid and reproducible) characterisations. Results : Diversity at the specimens' level corroborates the "standard” relationship between tanδ and E′/γ, which is discussed in terms of orientation of wood elements and of chemical composition. Diversity at the species level is expressed on the basis of results for normal heartwood, with specific gravity (γ) ranging from 0.2 to 1.3. Axial E′/γ ranges from 9 to 32GPa and tanδ from 4 × 10−3 to 19 × 10−3. Properties distribution follows a continuum, but with group characteristics. The lowest values of tanδ are only found in certain tropical hardwoods. Results can also suggest alternative species for musical instruments making. Conclusion : The variations in specific gravity, in stiffness or in "viscosity” appear to be predominantly linked to different levels of diversity: between species or between wood types (reaction wood or taxonomy-related differences in heartwood extractives