Bending and Compression strength of Portuguese Maritime pine small-diameter poles

Abstract

Portuguese pine forests frequently have high density due to the large number of young trees, which are maintained in the stands due to the high costs of thinning operations and the lack of financial return provided by the markets available for smalldiameter poles. With this problem in mind, a national project was launched to investigate the use of Maritime pine smalldiameter poles in structural applications. It is believed that this utilization could promote stand thinning operations by providing extra income to forest owners. Poles for the study were collected in an interior central region of Portugal and visually graded according to European standard EN1310. Poles were then tested (bending and compression) following European standard EN14251.The results obtained are presented and discussed along with the results obtained for round timber from other wood species and for Maritime pine strength graded structural timber with rectangular cross section. Considering future development of national strength grading standards (based on the results of this project), some correlations are presented between wood features and mechanical properties and between bending strength and stiffness. Good correlations were obtained between bending strength, density, and local modulus of elasticity (MOE). A significant difference in the bending strength between round and rectangular cross sections was observed but not for MOE.