For several years, Decision Aids has been addressing knowledge and technology transfer gaps in the design and construction sector that have had negative consequences for the image of wood. Since June 2000 we have been operating a public web site, together with the Canadian Wood Council, as a primary mechanism for conveying information to the building industry on wood durability. The web site’s popularity is growing, with October 2002 a record month for visits (3,748). In 2002/2003, we added substantial new material to the site, we brought the French side fully up-to-date, and we reconfigured the site’s appearance and structure. In 2002/2003, we also continued to develop our participation in building science academic development at UBC and BCIT. This kind of involvement with the universities that are teaching tomorrow’s building designers and consultants has become the preferred route for Decision Aids to meet its mandate for filling current knowledge gaps in durability. In particular, we have stayed closely aligned with BCIT in its pursuit of funding for the development of an outdoor test facility for building envelope assemblies. Such a facility will be an important tool for filling information gaps regarding best practice design with wood in rainy climates.
Forintek is Canada's primary source of test data on preservatives and treated wood, consequently it is imperative that Forintek maintain test sites representative of Canadian climates, particularly the worst case, southwestern B.C. Forintek's western field test site at Westham Island closed down in 1997 and work has been underway to establish a new site at the Malcolm Knapp Research Forest. This report documents the site evaluation, environmental status, site plan and location, soil preparation and trail relocation, soil characterization, a sediment runoff problem, sign shelter construction, fence treatment and installation and relocation of shingle and shake test racks. The test site was ready to receive above ground test material in the summer of 2002. Installation of ground-contact tests can proceed in summer of 2003.
In some western hemlock lumber pieces “brownstain” develops as the wood dries. Brownstain is deleterious to high-value appearance-grade stock because it reduces shop and better grades of hemlock to paint grade. The stain varies in color and can be superficial or subsurface. The incidence of subsurface brownstain, usually as a striped discoloration termed “zebra” stain has been seen more frequently with the increased kiln drying of western hemlock. When brownstain is subsurface, planing allowances have to be larger than desired, resulting in wasted fibre. A 1995 Forintek research project indicated that water storage of logs resulted in more surface brownstain during air drying than dryland storage but the numbers of logs were insufficient to determine if there was a significant difference. The project reported here was set up to investigate further whether storage influenced the development of brownstain and whether it occurred during kiln drying.
Three hundred cubic metres of hemlock logs were freshly cut, 60 m3 sent to a sawmill for conversion and the rest split between dryland and water storage. After two, four six and eight the stored logs were sawn in batches of 60 m3 into 100mm squares. These were examined individually before and after kiln drying and potential and observed brownstain marked of the faces. The squares were then planed and the extent of subsurface brownstain assessed.
Wet areas were apparent in both sapwood and heartwood of freshly sawn hemlock squares but were not useful in predicting the site of potential brownstain. Kiln drying gave the wood a toasted appearance in some of the drying runs which was removed by even the lightest planing. The most predominant form of brownstain was subsurface zebra (striped) stain which developed only during drying. Before planing, the presence of zebra stain was usually detectable as a shadow at the surface of dried lumber. This stain was up to 3 mm beneath the surface and therefore up to 3 mm had to be removed by planing to reach non-discolored wood. Zebra stain occurred only in the sapwood, usually the inner sapwood alongside the heartwood. The stain follows this zone along the boards. The zebra stain was more likely to be visible on edge-grain than on flat-grain, possibly reflecting moisture movement out of the boards. Some logs showed more zebra stain than others and appear to be predisposed to the stain. Both water and land stored logs, for short and longer terms, developed brown stain. Grey stain was also present but less common, and appears to be part of the natural character of hemlock wood. In general the longer the log storage time, up to 8 months, the less brownstain resulted, but based on the current information, changes in log storage type specifically to reduce development of brownstain are not justifiable.
In this work the lumber with the drier surfaces, which developed the least brownstain, was from the material that had been stored longest and included both water and dryland stored logs. There is an indication of interaction between log drying, storage time, air and kiln drying of lumber and the development of surface or sub-surface brownstain. Further investigation of these interactions may help to devise methods of reducing the incidence of hemlock brownstain.
Mechanical tree harvesters damage the exterior of freshly felled logs, loosening and removing bark, and producing punctures and indentations up to several centimeters deep. Damaged logs are susceptible to invasion by a plethora of wood inhabiting fungi. In this study, we investigated the role of tree harvesters in disseminating fungi, particularly wood-discoloring fungi, or inoculating Canadian lodgepole pine and New Zealand radiata pine logs.
In the study reported here wood decaying fungi, staining fungi and moulds were isolated from a harvester head and the bark of standing lodgepole pine trees. This microflora may be translocated into the sub-surface regions of a log during the harvesting process. In Canada, Aureobasidium pullulans was the most frequently isolated staining fungus followed by Ophiostoma minus and Leptographium sp. All were isolated from stained areas associated with damage sites. Sphaeropsis sapinea was the most prominent species in New Zealand. Tree harvesters clearly play a role in the dissemination of wood degrading fungi into freshly felled conifer logs.
Manitoba’s solid wood value-added sector is still in transition to a mature industry. There is a wide range of technical, product development, human resource, marketing, and industry development challenges yet to overcome for the industry to move to a position of world class.
It is within this context that the federal government, through the Canadian Forest Service (CFS), engaged Forintek Canada Corp to identify the technological needs of the secondary manufacturing industry in Manitoba.
The new reality for solid wood value adding, as well as for every other industry, is the crucial role of innovation for business development and growth. A relentless commitment to innovation is necessary to achieve and sustain global competitiveness. For this reason, research and technology must underpin everything that companies do, including product and market development, production, customer management, and environment and regulatory compliance and leadership.
Despite the diversity of product lines offered by different segments of the value-added sector, Forintek has identified many common technical issues that need to be addressed for the benefit of the industry as a whole. These issues relate to manipulating wood as a raw material through such processes as machining, drying, gluing, and finishing.
As well, based on Forintek's findings, a number of strategic priorities are recommended for moving the industry forward:
adopt a customer focus to meet changing needs and pursue new opportunities;
strive for continuous improvement and productivity gains for international competitiveness;
maintain a strategic focus on selected value propositions;
foster innovation throughout the Manitoba value-added industry, addressing research and technological issues on a common front wherever possible;
strive to strengthen & upgrade the overall competitiveness of the industry; and
continue to pursue global strategies to maintain a competitive edge.
By working together to address this wide range of business and technological issues, industry, government, and research and educational institutions have the opportunity to effect change and growth in the industry.