Qualidade da tora de espécies tropicais e rendimento em madeira serrada para exportação

Abstract

The low yield of sawn wood caused, among other factors, by the quality of the logs is one of the main problems of the timber sector. Therefore, the objective of this study was to evaluate the quality of logs and the yield of sawn timber for export of the Amazonian species Hymenolobium heterocarpum Ducke (angelim-pedra), Dinizia excelsa Ducke (faveiraferro), Dipteryx odorata (Aubl.) Willd. (cumaru), Qualea paraensis Ducke (cambará) and Astronium lecointei Ducke (muiracatiara). The experimental design was completely randomized, with 19 replicates (logs) for each of the five treatments (species). The data were collected in the AMATA S.A. timber industry, in the municipality of Itapoã do Oeste, in Rondônia, Brazil. Initially, were evaluated the parameters of the logs quality: conicity, flattening, bending, buttresses, diametral crack, surface crack, annular crack, heartwood percentage and net volume, and then the logs were grouped into quality classes. Then, the logs were deployed to obtain raw sawn timber and to determine the yield of sawn wood. For conicity and flattening, there was no significant difference between species, with mean values equal to 0.92 cm/m and 96%, respectively. Qualea paraensis presented the lowest percentage of logs with bending (5.26%) and the best classification for annular crack. Astronium lecointei was noted for not showing any log with presence of buttresses. Dipteryx odorata was the species that obtained the lowest frequency of logs with presence of surface crack (5.26%) and the best classification for diametral crack. For heartwood percentage, the species Dipteryx odorata (86.75%) and Hymenolobium heterocarpum (82.44%) presented the best results and did not differ from each other. For net volume, Dipteryx odorata (83.62%) and Hymenolobium heterocarpum (82.64%) had the highest mean values. The yield of sawnwood showed a significant difference between the species and ranged from 23.91% to 40.18%, respectively, for Dinizia excelsa and Qualea paraensis. It was concluded that there was great variation in the quality of the logs and the yield in sawn wood, due to the different characteristics of the evaluated species.