Caracterização física da madeira de Parapiptadenia rigida (Benth.) Brenan de um remanescente florestal

Abstract

In view of the lack of nutrients, such as the properties of timber species, in view of the great potential of machining, regarding the stability of the wood, for example in the, the objective of this work was to investigate the physical characteristics of Parapiptadenia rigida (Benth.) Brenan (angico-red) a forest remnant in southwestern Paraná. Five individuals were collected from an area of native forest remnant, of secondary stage, located on the campus of the Federal Technological University of Paraná, in the municipality of Dois Vizinhos, Paraná. Discs were taken to read the growth rings and determination of the mean age. Three discs of each individual were also removed at the (base, DAP and top) positions for determination of the base density. The logs were classified according to the mean diameter, giving rise to two diametric grades, being: Class I > 19.0 cm and Class II < 19.0 cm for conicity determination. The physical properties of maximum moisture content and dimensional variation in the tangential, radial and longitudinal directions were evaluated in two regions of the wood: near the marrow and close to the shell. The age found for the individual of P. rigida was 26 years with an approximate mean annual increment of 0.93 cm for that age. Regarding the conicity Class II presented a mean of 1.33 cm / m, taper smaller than Class I, average of 1.83 cm / m, without significant difference by the paired t Test, classified according to the IBDF superior and / or class I. The result obtained of average basic density for the wood of P. rigida was of 0.719 g /cm³ so being considered a mediumheavy wood. The results showed that there was no significant difference between the means of density in the three positions of the shaft. As for the maximum moisture content possible to be found in the wood, for the two regions of the trunk there was no significant difference between the means according to paired t-test. For the wood closest to the bone marrow the maximum was 64.45% and for the wood closest to the bark 61.44%. The average for the tangential, radial and longitudinal retraction coefficients were, respectively, 8.10%, 6.20% and 0.22%. The values of retraction and swelling in the tangential direction differed statistically between the two regions, with the proximal portion of the medulla with Ɛr = 7.26% and Ɛi = 7.86%, smaller variation in relation to the close portion of the shell with Ɛr = 8.94% and γi = 9.82%. The wood of P. rigida had a mean volumetric coefficient of variation of 16.28%, thus considering the wood referring to this factor, as regular. The mean value for the anisotropic factor found for P. rigida was 1.31 and considered to be dimensionally stable.