Influence of spacing on some physical properties of Schizolobium parahyba var. amazonicum (Huber ex Ducke)

Abstract

Schizolobium parahyba var. amazonicum, which is known in Brazil as paricá, has been highlighted in commercial plantations in Northern Brazil, mainly due to its fast growth. However, the choice of the ideal spacing, in which a higher proportion of good quality wood is obtained, constitutes an issue to be considered in research on paricá forest management. The objective of this study was to verify the influence of spacing on basic density, tangential and radial shrinkage, volumetric shrinkage and anisotropic factor of 9-year-old paricá wood, as well as variation of such properties from pith to bark. An entirely randomized design was used, arranged in a 2 x 4 factorial scheme (2 spacings and 4 radial positions) and 5 replications in 4 x 4m and 8 x 4m spacings, with a total of 10 sample trees obtained in the municipality of Garrafão do Norte/PA. In each tree were obtained 8-cm thick disks were obtained at 1.3m from ground level. The radial position from pith to bark was divided into four parts: at 0% (near the pith), at 33 and 66% along the radius, and at 100% (near the bark). The results indicated that spacing among trees had no significant effects on physical properties. Basic density and tangential shrinkage showed an increasing trend from pith to bark, while the reverse trend was observed for radial shrinkage. Significant differences were not observed for volumetric shrinkage and anisotropic factor as a function of radial positions.