Clonal consistency of wood technological properties in canker-resistant Cupressus sempervirens clones at two contrasting sites

Cupressus sempervirens L. (Mediterranean cy- press) has been traditionally used as a multipurpose tree. In the past, its wood was extensively used as a highly durable raw material in the Mediterranean, but nowadays, production of cypress wood is constrained by the lack of exploitable woods and plantations and by the spread of bark canker. In this study, the wood properties of canker-resistant clones spe- cifically meant for timber production were assessed in two different locations. The aim was to evaluate the effect of ge- notype and environment on physical and mechanical proper- ties of wood and its bonding quality. Four ramets of each of 10 clones were sampled in both sites, wood density, shrink- age, hardness, and the bonding strengths when glued together with two different adhesives were determined, and clonal re- peatabilities and genetic correlations were also estimated. Clonal consistency for wood traits was moderate to high with- in and across environments, far higher than for growth- and morphological traits. Indications are that selection based ex- clusively on tree height would result in a lower wood density and hardness. Bonding strength reflected the combination of the material properties and the selected adhesive: For adhe- sive M (polyvinyl acetate dispersion), it was negatively cor- related with density, whilst for adhesive E (emulsion polymerization isocyanate), it was not as influenced. Thus, even favouring higher-density wood (and therefore not only hardness but also higher shrinkages), adhesive E would give excellent bonding.