The absence of commercial facilities to recycle or recover value from wood treated with metal-based wood preservatives at the end of its service life is one of the most significant negative points in the generally positive life cycle analysis of treated wood. Wood treated with carbon-based preservatives (metal-free) may be far easier to recycle or recover value from since the preservatives are relatively vulnerable to thermal, chemical and biological breakdown. As a result they might be destroyed by kraft pulping, combustion or composting of treated wood. The present research evaluates the use of carbon-based preservative-treated wood in these processes.
Kraft pulps produced from wood freshly treated with recommended loadings of carbon-based preservatives contained significant quantities of didecyldimethylammonium carbonate (DDAcarbonate), propiconazole and tebuconazole. However, lower preservative concentration in the wood and intensive pulping may be able to produce pulps without detectable preservatives. The azoles were also detected in significant quantities in the black liquor (DDAcarbonate was not analysed in black liquor).
No azoles were found in the ash produced from combustion, but significant quantities were detected in the filtered smoke. DDAcarbonate was not detected in the filtered smoke. Analysis of DDAcarbonate in ash was inconclusive.
A composting experiment has been set up and is in progress. Data on preservative breakdown during composting is expected next year.
To better understand the role extractives play in western red cedar’s decay resistance, commonly detected but unknown extractives need to be identified and evaluated for their potential contribution to natural durability. A new liquid chromatography/mass spectrometry (LC/MS) method for separating extractives from western red cedar has been developed. Mass spectral detection provides useful structural information that gives increased confidence in peak identifications and helps to identify unknown peaks. Using LC/MS data, combined with data from UV and NMR spectroscopy, unknown compound J commonly found in many samples of WRC we have analysed, was identified as alpha-thujaplicin. This was known to be a major extractive in eastern white cedar but was considered to be a negligible component of WRC. Its potential contribution to the durability of WRC has not been considered in previous work attempting to correlate durability to specific extractives.
The objectives of the project are to determine the major source of bluestain fungi and determine the mechanisms of their dispersion, and to determine the biology and weak points of pests that may be expoited to control them.
This is a discussion paper addressing the factors involved when considering the total environmental footprint of wood doors. The discussion is within the context of a new amendment to BC energy regulations affecting doors and the subsequent market shifts that will occur as a direct result. The energy regulation applies a U-value threshold to doors. U-value is a physical (thermal) property of an assembly indicating the rate of conductive heat flow through the assembly. A maximum U-value for doors is being specified in BC that cannot be met by the current commonly-manufactured configuration for solid wood doors. In this paper, a life cycle assessment (LCA) approach is used to discuss the broader environmental picture beyond the single criterion of U-value, specifically focusing on the trade-off between embodied energy in a product and the impact of that product on the operating energy of the building in which it is installed. Any change to the current manufacturing process for wood doors for the purpose of improving thermal characteristics should be done within an LCA perspective so that the changes don’t inadvertently lead to a net increase in total lifetime energy consumption. Similarly, any market shift to non-wood alternatives for doors should also be done within an LCA perspective for the same reason. A detailed and precise analysis of door footprints requires LCA data and energy simulation results, both of which are beyond the scope of this study. In place of full LCA data, we accessed existing literature and existing partial LCA data (from the Athena Institute) to roughly estimate the embodied energy differences between door types, and to discuss the other environmental impacts of a substitution from today’s common wood doors to non-wood alternates. Three generic door types were compared: wood, steel and fibreglass. In all the environmental metrics examined, including embodied energy, the wood doors have the lowest impact. Although insulated steel and fibreglass doors typically have a lower U-value than wood doors, they involve more energy consumption in their manufacturing. This means that the added energy investment in steel and fibreglass doors will require some time to be paid back through reductions in a home’s heating and cooling costs. Similarly, an improvement to wood doors to reduce U-value may increase the embodied energy, requiring a payback period that may or may not be reached within the lifetime of the door.
Softwood and hardwood logs and lumber are susceptible to sapstain from the time the tree is felled, during storage prior to processing, and after processing. As part of the project, Biology and Management of Bluestain, we aim to help the industry to extract the most value from wood by finding ways to prevent bluestain and other biodeterioration during wood storage and transport. Recently we investigated the feasibility of using controlled atmosphere storage to inhibit the growth of sapstain fungi. This involves wrapping and sealing green logs or lumber immediately after harvesting in UV-resistant and gas-impermeable sheets. This allows CO2 to build up to 20-40% due to microbial and live wood cell respiration, while oxygen gets depleted to near zero levels in a few days. This ecologically friendly storage method does not depend on climate, storage site, tree species or size of pile. It may be used in areas where other methods are not available and in nature-conservation, water protection and other ecologically sensitive areas. Logs have been shown to remain sound for up to four years. The process has been patented in Germany and has been used in Europe on a commercial scale but has limited exposure in North America. This paper reviews existing knowledge and experience with this process and assesses the feasibility of using it in Canada for Canadian wood species. It also aims to recognize key knowledge gaps that may need to be addressed before the method is presented to the industry as a viable and economical option for safe storage of wood on a large industrial scale.
The objectives of the project are to develop two-way technology transfer instruments that achieve a connection with specifiers, designers, builders, homeowners and maintenance supervisors and to explore opportunities for collaborative field studies of durability performance where information gaps exist.
Bluestain reduces the value of wood in appearance applications where the natural wood colour is desired. Treatments that remove bluestain without degrading the natural colour of the wood could make this lumber more suitable for appearance-grade applications.
FPInnovations and UBC have each previously developed methods of decolourising bluestain but both resulted in unacceptable colourations in the wood (Binnie et al., 2000; Evans et al., 2007). Follow up work at FPInnovations found that the combination of hypochlorite bleaching and exposure to UV and visible light was able to remove bluestain from lodgepole pine (Stirling and Morris, 2008). The present work identified the minimum treatment times required for effective bluestain removal to be a 10 minute bleaching dip and 10 minutes of exposure to intense light. Near- and mid-infrared spectra indicated changes in surface chemistry after treatment. However, adhesion tests showed no signs of reduced coating adhesion caused by UV damage or hypochlorite exposure.
