Physical and mechanical property variation of black ash (Fraxinus Nigra M.) grown in the Thunder Bay seed zone

Abstract

The identification of traditionally underutilized species with the potential for development and increased marketing potential has been recognized as a source of potential innovation in the Northwestern Ontario forest sector. However, the industry requires improved knowledge of the physical and mechanical properties of these species and how this information can be applied to end use attributes in value added forest products. Black ash (Fraxinus nigra Marsh.) is abundant throughout the region, yet has been identified as an underutilized species with limited available literature on properties or potential variations. Nine mature black ash trees from the Thunder Bay Seed Zone were destructively sampled and wood properties in differing radial and longitudinal positions were measured and recorded. Longitudinal positions reflect 0, 25, 50 and 75 percent of total merchantable height. Radial positions reflect the juvenile wood core, transition zone and mature wood of each stem. Measured wood properties include MOE, MOR, compression parallel to the grain, Janka ball side hardness, relative density, ring width, latewood percentage and average ring density. Results indicate stable and predictable wood properties in the radial direction with only percentage of latewood varying significantly radially. Longitudinal position reflected increased variance with MOE, compression parallel to the grain, side hardness and ring width displaying significant results. The greatest level of variability was observed between sites in each of the selected properties. Results consistently displayed two subsets of sites; reflecting the second and third sites, or three distinct sites. Increased mechanical property values were identified in the upland and well-drained sites as compared to the lowland site. In the future, benefits exist for increased processing potential, as inherent properties are consistent throughout the tree including the desirable heartwood section. It was determined that site conditions play a significant role in the inherent wood properties and opportunities exist for forest managers to predict mechanical properties based on site characteristics.