Basic density of wood from Pinus caribaea var. hondurensis grown in the cerrado area

Wood basic density is the most important physical characteristic of wood, because it is correlated with other physical, anatomical, mechanical and chemical properties. The utilization of wood with greater uniformity of density through the trunk is always desired. In this context, the evaluation of the density variation between axial positions is a good method of checking the density homogeneity. This study aimed at analyzing the radial (pith-bark) and axial (bottom-top) density variation of wood from Pinus caribaea var. hondurensis. Five trees were felled and 16 discs of 2.5 cm thick were crosscut consecutively from the bottom to the top of the tree. From each disc two, opposite wedges were cut (east and west) and divided into five subsamples from pith to bark (1-pith, 2, 3, 4 and 5-bark). The basic density of each subsample was determined by using maximum moisture content method. The results showed that the mean basic density was about 0.605 g/cm(3), and was decreasing to 0.505 g/cm(3) around the 5th disc and remaining this value up to the 16th disc. The wood density increased from the pith (0,488 g/cm(3)) to the bark (0,518 g/cm(3)), but a reduction was observed between subsamples 4 and 5. According to the results of the analysis of regression, the wood basic density of Pinus caribaea var. hondurensis could be best fitted by using the value observed in the 3rd disc (R-2 = 0.62); or in the sample evaluated 1.80m from the bottom. The basic density presented more homogeneous values between 5th and 16th disc.