The Forest Engineering Research institute of Canada (FERIC) conducted a study to assess the reliability, effectiveness, and cost of airborne infrared remote sensing, mapping and analysis systems used in Alberta. Field trials were conducted to develop assessment methods and to facilitate preliminary tests of the hotspot detection capabilities of two airborne infrared remote sensing systems: an AWIS (Airborne Wildfire Intelligence System) mounted on a twin-engine aircraft, and a FLIR 2000 mounted on a "birddog" aircraft. Logistic regression was used to develop probability of detection models for each of the sensor and aircraft platforms evaluated. This report also describes the development of a simple model that allows fire managers to assess the cost effectiveness of alternative technologies.
Fourier Transform Infrared spectroscopy (FTIR) has been identified as a potential analytical method that might improve monitoring of sapstain control chemicals application in sawmills. The main benefit from use of this technique would be the ability to respond immediately to application problems identified. Based on preliminary laboratory data Bomem Inc., Forintek Canada Corp. (FCC) and the Pacific Forestry Centre (PFC) agreed to undertake research aimed at the development of FTIR for commercial application in sawmills. The first stage in this project was to validate the FTIR method in the laboratory. A protocol was agreed upon for a test which would determine the precision of the FTIR retention predictions on a variety of wood surfaces. Wood strips of rough, planed and intermediate surface texture were prepared. At FCC a technique was devised by which the wood strips were treated with known amounts of DDAC. Intermediate textured replicate samples were treated to known retentions of DDAC and sent to PFC to use in calibrating the FTIR instrument. Additionally, 20 replicates of each surface texture were treated with random amounts of DDAC over the range 0 - 200ug/cm squared. These "unknowns" were also sent to PFC for analyses by FTIR and prediction of DDAC retentions. Although correlation between actual and predicted DDAC retentions was linear within a particular surface texture, results show a mean difference or error between the actual (weight uptake) and FTIR determinations of DDAC retentions of 46% (standard deviation 28%). Therefore, overall, the FTIR analytical method gave unsatisfactory results. Our conclusion is that, based on the current calibration, the FTIR analytical method is not sufficiently accurate for general sawmill application. The surface texture of the wood being scanned significantly affected the retention of DDAC as determined by FTIR and corrections for surface texture would need to be incorporated into the software if further development was to be considered. Additionally, other variables than surface texture (e.g. formulation additives) may influence analytical results and were not considered in this study.
Wood is very susceptible to weathering when used outdoors because of its inherent nature of UV degradability and dimensional instability. Without effective protection, wood rapidly loses its attractive natural appearance and becomes unserviceable within a few years. Protection has traditionally taken the form of system design to avoid trapping water, and surface finishing to shed water and prevent UV degradation. Unfortunately, surface finishes such as paint and stain last only a few years and the need to repeatedly refinish wood has led to the perception of wood products as high maintenance building materials. The objective of this project is to develop fundamental information leading to processes which can be used by our industry to produce high- performance wood products with extended service lives and low maintenance requirements. The project has been focusing on UV resistance to the present stage. Wood samples were treated with chemicals that have UV stabilizing properties and their weathering performance evaluated by both accelerated and natural weathering tests. UV-visible spectroscopy was used to monitor the color change, and FTIR (Fourier Transform Infrared spectroscopy) was used to monitor lignin degradation on the wood surface. Rate of erosion, water absorption, and dimensional change during accelerated weathering was also studied. Preliminary weathering results are discussed in this report and recommendations made for further research.
Wood preservation standards typically specify quality assurance procedures to determine whether wood is adequately treated. As a result there is a need to identify sapwood and heartwood, and measure preservative retention and penetration. For spruce and hem-fir there are no reliable methods to differentiate sapwood and heartwood. For carbon-based preservatives, preservative retention measurement typically requires GC or HPLC analyses; the only methods available to determine penetration involve detecting a surrogate in the formulation rather than the active ingredients. Multivariate models based on near infrared (NIR) spectra have been used to predict a wide range of wood properties over the past 20 years. The present research evaluates the potential use of NIR-based models as quality assurance tools for the wood preservation industry. Models were developed to differentiate hemlock and amabilis fir sapwood and heartwood. Attempts to differentiate spruce sapwood and heartwood were unsuccessful. NIR-based models were also able to differentiate untreated wood from wood treated with DDACarbonate and wood treated with tebuconazole. Models developed to predict DDACarbonate and tebuconazole retention were moderately accurate, but likely not precise enough to replace current quantitative assays. However, the sensitivity to the presence of the actives may be sufficient for estimating preservative penetration. Further work is needed using small probes suitable for scanning increment cores to adapt this technology for industrial use.
In addition to conventional NIR, hyperspectral images were obtained to differentiate untreated wood from DDACarbonate- and tebuconazole-treated wood, but accurate calibrations could not be developed.
Recent work suggested that near infrared (NIR) spectroscopy may be able to estimate extractive concentration in western redcedar (WRC) heartwood. This would facilitate the screening of breeding stock that will produce durable heartwood. Increment cores from 50 trees were scanned and analysed for extractives content to evaluate existing models. Extractives data were not accurately predicted by the developed models. This was likely due in part to the much smaller range of extractives in the increment core data set. Subsequent partial least squares (PLS) models based on the increment core data set confirmed that NIR is not sensitive enough to small variations in extractives to differentiate wood with small or medium differences in extractives content.
The present work also examined the ability of PLS models to predict decay resistance from NIR spectra. The developed models were not able to accurately predict weight loss caused by Coniophora puteana in a soil block test. Correlations between extractives data and decay resistance data were very weak. This weakness may have been exacerbated by the leaching and biodegradation steps that would have reduced the concentration of thujaplicins in the samples.
