Wood properties of exotic larch grown in eastern Canada and north-eastern United States

Abstract

The rapid growth performance of exotic larch such as Japanese larch (Larix leptolepis (Sieb. et Zucc) Gord.) and European larch (Larix decidua Mill.) has attracted the attention of the forestry sector in eastern Canada and north-eastern United States for lumber and pulp production. While growth performance of these species in North America has been well documented, little is known with regards to their wood properties. The objective of this study was to evaluate the primary lumber grade yields, mechanical properties, fiber length, specific gravity and cold-water soluble extractives of larch from plantations in Maine, Nova Scotia, New Brunswick and Prince Edward Island. Samples were obtained from a Japanese (age 31), three European (age 17, 34 and 63) and one Japanese × European hybrid (age 22-27) larch stands. It was found that the structural grade yields of these species were relatively low because of the influence of knots. The mechanical properties (modulus of rupture and modulus of elasticity) of the mature European larch appeared to be comparable with published data for some native softwood species. Fiber length, specific gravity and cold-water soluble extractive content of all samples were similar to those found for other softwood species which are used for pulp production. Fiber length of the juvenile wood of European larch was significantly shorter than that of mature wood. Extractive content was highest in newly formed heartwood. Contrary to common belief, extractive content in young trees may not be low. Key words: Japanese larch (Larix leptolepis Gord.), European larch (Larix decidua Mill.), European × Japanese hybrid (Larix eurolepis), Wood properties, Lumber yields