CARACTERÍSTICAS QUÍMICAS E FÍSICAS DA MADEIRA DE MOGNO AFRICANO (Khaya ivorensis A. Chev.)

A demanda pela madeira de mogno africano (Khaya ivorensis) e crescente, visando suprir o setor de produtos serrados. Para atender ao mercado madeireiro, a aptidao tecnologica das especies, geralmente e verificada atraves da avaliacao das suas caracteristicas inerentes. O objetivo deste trabalho foi quantificar ao longo do tronco, os extrativos, lignina e a massa especifica basica dessa especie. O material analisado foram quatro arvores provenientes de um plantio homogeneo de 10 anos, localizado em Mato Grosso. As subamostras foram retirados nas porcentagens de 0, 25, 50, 75 e 100% da altura comercial das arvores. As analises quimicas tiveram como referencia as normas da ABTCP (1974) e os ensaios fisicos, as normas da ABNT/NBR 11941-02 (2003).  Na quantificacao de extrativos, a agua fria apresentou a menor media (3,91%) e o hidroxido de sodio a maior (20,57%). O teor medio de lignina foi de 30,29% e a massa especifica media foi de 0,530 g cm-³. Os dados foram analisados com base na analise de variância, teste de medias e componentes principais (ACP). Concluiu-se que a madeira estudada apresentou caracteristicas tecnologicas compativeis para ser utilizada na area moveleira, e tambem em construcoes externas, mostrando potencial competitivo para atuar no setor.Palavras chave: extrativos; lignina; massa especifica basica; qualidade de madeira. CHEMICAL AND PHYSICAL CHARACTERISTICS OF AFRICAN MAHOGANY WOOD (Khaya ivorensis A. Chev.)  ABSTRACT: Demand for African mahogany (Khaya ivorensis) wood is increasing to supply the sawn timber sector. To cater to the timber market, the technological suitability of the species is generally verified by assessing their inherent characteristics. The objective of this work was to quantify along the trunk the extractives, lignin and the basic specific mass of this species. The analyzed material were five trees from a homogeneous planting of 10 years, located in Mato Grosso. The subsamples were taken in percentages of 0, 25, 50, 75 and 100% of the commercial height of the trees. The chemical analysis had as reference the ABTCP (1974) norms and the physical tests, the ABNT/NBR 11941-02 (2003) norms. In the quantification of extractives, cold water presented the lowest average (3.91%) and sodium hydroxide the largest (20.57%). The average lignin content was 30.29% and the average specific mass was 0.530 g cm-³. Data were analyzed based on analysis of variance, means test and principal components (PCA). It was concluded that the woodstudied presented technological characteristics compatible to be used in the furniture area, as well as in external constructions, showing competitive potential to operate in the sector.Keywords: extractives; lignin; basic specific mass; quality wood.