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The physical and mechanical properties of poplar clones largely determine their suitability for various end-uses, especially for high valueadded applications. The main objective of this study was to determine the clonal variation of selected physical and mechanical properties of seven hybrid poplar clones grown at three sites in southern Quebec, Canada. Five trees per clone were randomly sampled from each site for wood properties measurement. Site had a significant effect on all measured properties except radial shrinkage. All properties of hybrid poplar wood showed significant interclonal variation, indicating the possibility of identifying clones with superior wood properties, especially for density, flexural modulus of rupture, and ultimate crushing strength. High heritability values for the studied properties indicated that these properties are under moderate to high genetic control. The genetic gain for these wood properties ranged from 2.0% to 13.5%.

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Twelve years old Japanese larch (Larix kaempferi [Lamb.]) trees of 20 different progenies and/or provenances were sampled at one site in the Mauricie region of Quebec. Two standard samples were obtained at breast height and closer to the bark from each tree. Partial and total radial, tangential, and volumetric shrinkages, and tangential/radial (T/R) shrinkage ratios were assessed. All of these variables were significantly affected by the progeny/provenance. Drying defects are one of the main reasons for downgrading larch lumber, thus T/R shrinkage ratio was considered for the selection of progenies/provenances for lumber production purposes. Lowest partial and total T/R shrinkage ratios were obtained with progenies/provenances 8964, 8904, 8962, 8957, 8907, 8927, 7283 and 7795. Among them, lowest partial and total tangential, radial, and volumetric shrinkages were found in progenies/provenances 8964, 8962, and 8907 as well. Other physicochemical (mechanical properties, density, extractive content) and silvicultural (growth rate) attributes should also be taken into consideration for an adequate selection of progenies/provenances according to the specific final utilization.

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