Selected properties of hybrid poplar clear wood and composite panels

Eleven hybrid poplar clones grown in the inland and coastal regions of the Pacific Northwest were studied. Small, clear specimens were tested to determine specific gravity, shrinkage, and bending properties. Oriented strandboard (OSB) panels were fabricated and tested to determine flexural properties, internal bond, density, water absorption, and thickness swell. Clear wood properties of the hybrid poplar clones were lower than those of native aspen and cottonwood species. Differences were observed among the clear wood mechanical and shrinkage properties for the clones, indicating potential for selective breeding to genetically engineer trees with targeted structural end uses. OSB produced from individual clones performed beyond industry specifications for mechanical properties and moisture resistance. Future research is needed to evaluate the use of hybrid poplar in composite lumber products.