Axial variation of basic density of Araucaria angustifolia wood in different diameter classes

Variação axial da massa específica básica da madeira de Araucaria angustifolia em diferentes classes diamétricas

ABSTRACT:

The study of the wood characteristics is of fundamental importance for the correct use of this raw material and, among its properties, the basic density is a major, being reference in the quality of this material. This study aimed to evaluate the axial variation of basic density of the wood ofAraucaria angustifolia (Bertoloni) O. Kuntze in different diameter classes. For this, three trees were selected in six diameter classes, called class 1 (20-30cm), class 2 (30.1-40cm), class 3 (40.1-50cm), class 4 (50.1-60cm), class 5 (60.1-70cm) and class 6 (70.1-80cm). From each individual sampled was withdrawn a disc at 0.1m (base), 25, 50, 75 and 100% of the height of the first live branch and in the diameter at 1.30m from the ground (DBH), which were used for determining basic density. The weighted average basic density was equal to 0.422g cm^-3 and, regardless of the diameter class analyzed, this property decreased in the axial direction. Diameter induced variation of basic density, but has not been verified a positive or negative systematic tendency in relation to the sampled interval.

Key words:
Brazilian Pine; wood technological characteristic; wood quality