MÉTODOS DE CUBAGEM E ESTIMATIVA DA DENSIDADE VERDE DA MADEIRA DE Pinus taeda L. EM DIFERENTES IDADES E SORTIMENTOS

Abstract

Currently, wood measurement in most companies is performed in tons by weighing the trucks, however, wood pricing is based on its solid volume in cubic meters. To convert this unit of mass to solid volume, companies adopt an average conversion factor. This generic approach can result in inaccurate estimates, as it does not consider factors such as age and assortment, which can affect green density. Based on these considerations, this study aimed to compare different wood scaling methods and understand the variation in green density of wood at different ages and assortments in Pinus taeda L. plantations. The research was conducted at the Lageado Grande farm in Bituruna, Paraná, in P. taeda plantations aged 11, 15, and 19 years with spacings of 3 m x 2 m, 2.5 m x 2.5 m, and 2.5 m x 2.5 m, respectively. For the comparison of scaling methods, a randomized block design (RBD) was used in a factorial scheme, with three scaling methods (Smalian, Huber, and Newton) and different assortments (S1: 6-13 cm; S2: 13-18 cm; S3: 18-23 cm; S4: 23-33 cm; and S5: >33 cm), in six blocks with 10 logs per block, aiming to compare the volumes with and without bark at three distinct ages (11, 15, and 19 years) and three assortments (S1, S2, and S3) at the age of 11 years, four (S1, S2, S3, and S4) at the age of 15 years, and five (S1, S2, S3, S4, and S5) at the age of 19 years. For the evaluation of moisture content, basic density, and green density, the experiment was RBD in a factorial arrangement of three ages (11, 15, and 19 years) in different assortments, as previously described. The scaling methods differed in terms of age and type of assortment. For ages 11 and 19 years, regardless of the type of assortment, any of the evaluated methods (Huber, Smalian, Newton) can be used as they did not show significant statistical differences. For the age of 15 years, for assortments S1 and S2, any of the methods can be used, and for assortments S3 and S4, the Huber and Newton methods were the most recommended. In the evaluation of initial moisture content, basic density, and green density, all variables were influenced by age and type of assortment. Moisture content values decreased with increasing age, while basic density increased. Green density increased with age and decreased with increasing assortment classes. The results indicated that the Huber method tends to provide the most consistent volume estimates with less variation across different ages and assortments. To determine the conversion factor from weight to volume using green density, it is recommended to consider the variations identified between ages and assortments to obtain more accurate estimates.