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To extend service life in exterior cladding applications, wood must be treated and/or coated. White spruce (Picea glauca (Moench) Voss) is a common wood species used in Canada for exterior cladding applications. White spruce is a refractory species and can be hard to treat with conventional approaches. Organosilanes could be an interesting wood treatment as condensation between organosilanes and wood hydroxyls can occur leading to a decrease in hydroxyl content, which are responsible for the dimensional instability of the wood. White spruce was pressure-treated with different formulations of organosilanes using acid and basic catalysts as well as hydrolysed and non-hydrolysed organosilanes. Weight percent gains were quite low (up to 11%) due to white spruce anatomy, and also because the organosilanes were located only in the cell wall. White spruce treated with organosilanes showed the best anti-swelling efficacy (up to 30%) for a non-hydrolysed formulation using an acid catalyst and the smallest organosilane molecule. The basic catalyst did not improve the anti-swelling efficacy compared to the acid catalyst because of its low mass gain. Three types of commercial coatings were applied on the treated wood and untreated control. The coated samples were submitted to accelerated UV exposure for 1,500 h to evaluate colour change and adhesion. The opaque stain exhibited the smallest total colour change (ΔEab*) with or without the modification of organosilanes. [ABSTRACT FROM AUTHOR]

Diameter at Breast Height (DBH) plays an important role in forest management. New technologies such as airborne and terrestrial Light Detection and Ranging (LiDAR) are expensive and time-consuming. We explored the iPad LiDAR sensor to measure DBH considering affordability and availability. The study was carried out at a research forest plantation near Thunder Bay, Ontario, Canada. Five plots were selected for differences in stem spacing, average DBH and species, and made 360° scans separately. A manual circle fitting method was used to produce circular features for the estimation of DBH. The coefficient of determination (R2) between estimated DBH and field measurements was 0.52, indicating a moderate accuracy. The Root Mean Square Error (RMSE) of DBH estimation ranged from 2.82 cm to 8.24 cm. The accuracy of smaller red pine trees was found to be relatively higher than that of larger red pine and white spruce trees. These accuracies did not change with the distance from the scanning location to trees. Therefore, results showed the potential use of an iPad LiDAR Scanner for DBH estimation. We recommend developing an application combining the iPad's location and LiDAR sensors and incorporating a precise positioning method for fieldwork, and further broad field testing. [ABSTRACT FROM AUTHOR]

In Canada, the coniferous forest was generally found to be nitrogen (N) deficient, but base cation deficiencies may be becoming more prevalent. Newly-developed nutritional standards based on leaf nutrient concentrations and compositional nutrient diagnosis (CND) were applied on published data of white spruce nutrition from sites across Canada. Results suggest that nutritional disorders in white spruce are not restricted to N deficiencies. Based on nutrient concentrations, deficiencies are common, particularly in phosphorus (P), potassium (K), and calcium (Ca), but toxicities are rare. The CND analysis revealed some cases of excess N, P, and magnesium (Mg). [ABSTRACT FROM AUTHOR]

The objectives of this study were (1) to compare six methods for predicting parameters of the Weibull probability density function (PDF) for diameter at breast height (dbh) distribution in the unthinned white spruce plantations in eastern Canada with respect to their applicability, and (2) to evaluate their predictive abilities in terms of error index (EI) and Kolmogorov-Smirnov (K-S) statistic. The reasons for undertaking this study were (1) there are no available models for the dbh distributions of the studied species and (2) to determine the best method for projecting dbh distributions of white spruce plantations. A total of 113 sample plots which consisted of the commonly measured stand-level variables [stand age (A), site index at 25-year base age (SI), average height of dominant and co-dominant trees (Hd), and stand density (SD)] and associated diameter frequency distributions were used in this study. Of all the six prediction methods, the moment-based and percentile-based parameter recovery approach (PRM and PCT), maximum likelihood estimation regression (MLER), cumulative distribution function regression (CDFR) and parameter prediction method (PPM) were able to be applied for adequately modeling the diameter frequency distributions for the data sets used in this study. The moment-percentile estimation hybrid method (HYBM) performed the poorest. PCT was most highly recommended as it had the consistently lowest EI and K-S statistic values for both fit and validation data sets. Therefore, the dbh distributions for white spruce plantations could be predicted at a point over time using the established methods here, especially the PCT method, from the stand variables (A, SI, Hd, SD). [ABSTRACT FROM AUTHOR]

The incidence of type 2 diabetes mellitus has reached epidemic proportions worldwide. Canadian aboriginal communities, particularly the Cree Nation of Eeyou Istchee, have been identified as a high-risk population. Culturally acceptable treatment options are limited notably for diabetic complications resulting in peripheral neuropathy. Here, we describe results of an ongoing collaborative research project with Cree of Eeyou Istchee to identify botanicals capable of protecting peripheral neuronal precursors from glucose toxicity and glucose deprivation in vitro. Polar fractions of three plant organs (needles, cone, and bark) collected from Picea glauca (Moench) Voss (Pinaceae), were tested for toxicity under normoglucose, glucotoxicity, and glucose deprivation conditions. The profile of phenolic metabolites in each extract was first characterized by high-performance liquid chromatography-diode array detection-atmospheric pressure chemical ionisation mass spectrometry (HPLC-DAD-APCI/MS). We report here that these fractions are well-tolerated by PC12 neuronal precursors under normoglucose conditions. LD50 concentrations of needle extracts exceeded 100 μ g/mL, whereas the LD50 of bark and cone extracts was 40 and 36.4 μ g/mL, respectively. We further show that the cytoprotective properties of minhikw after glucose challenge are concentration-dependent and organ-specific. Needle extracts protected PC12 cells from both glucotoxicity and glucose deprivation. Bark extracts had negligible activity. Cone extracts further impaired PC12 cell glucose tolerance. This study provides the first validation of antidiabetic activity of minhikw organs at the cellular level relevant to the management of diabetic peripheral neuropathy. [ABSTRACT FROM AUTHOR]