Composição química e estabilidade dimensional da madeira de três eucaliptos

In this study correlations between chemical composition and dimensional stability of Eucalyptus botryoides, Eucalyptus paniculata e Eucalyptus tereticornis were evaluated. Specimens were prepared from five different positions in radial direction, corresponding to 0, 25, 50, 75 e 100%, from pith to bark. For physical analysis, samples mass and dimensions were measured above saturation point, at conditioned temperature (20°C and 65% of relative humidity) and oven dried (103 ± 2°C). In each step density at 12% (ρb), as well tangential (βT), radial (βR) and volumetric (βV) shrinkage were calculated. Samples from same positions were chemical evaluated concerning to soluble extractives in ethanol-toluene, insoluble lignin, hemicellulose and α-cellulose. It has been observed similar behavior among eucalypt wood. Lignin and density showed positive correlation, both increasing from pith to bark, while hemicellulose presented negative correlation with density and extractives negative correlation with shrinkage.