Resumo As alterações na qualidade da madeira das árvores de Eucalyptus causadas pela fertilização e disponibilidade hídrica podem influenciar as características da biomassa e do carvão vegetal. O objetivo deste trabalho foi avaliar as características da madeira e do carvão vegetal de Eucalyptus grandis sob o efeito da fertilização com potássio e sódio (controle; 4,5 kmol ha-1 de KCl e 4,5 kmol ha-1 de NaCl) e disponibilidade hídrica (100% e 63% das chuvas, com exclusão artificial por lonas em polietileno). Árvores de Eucalyptus de cada tratamento de fertilização x disponibilidade hídrica, com cinco anos de idade, foram cortadas e obtidas amostras, na altura do DAP para a caracterização energética e física da biomassa e do carvão vegetal. A aplicação da fertilização com K e Na não influenciou as características energéticas e físicas da biomassa e do carvão vegetal. A exclusão parcial da água da chuva na plantação florestal de Eucalyptus grandis promoveu alterações nas características da biomassa e do carvão vegetal, com redução do teor de cinzas, aumento da densidade da madeira e do carvão vegetal e rendimento gravimétrico do carvão vegetal.

Abstract Changes in the wood quality of Eucalyptus trees caused by fertilization and water availability may influence the characteristics of biomass and charcoal. The aim of this study was to evaluate the effects of potassium and sodium fertilization (control; 4.5 kmol ha-1 of KCl and 4.5 kmol ha-1 of NaCl) and water availability (100% and 63% rainfall with artificial exclusion) on the energetic and physical characteristics of biomass and charcoal. Eucalyptus trees of each fertilization x water availability treatments, at five years old, were cut down and the samples were taken at the DBH for the energetic and physical characterization of biomass and charcoal. The application of fertilization with K and Na did not influence the energetic and physical characteristics of biomass and charcoal. The partial exclusion of rainwater in the Eucalyptus grandis forest plantation promoted changes in the characteristics of biomass and charcoal, with reduction of ash content, and increase of wood and charcoal density and the charcoal gravimetric yield.

ABSTRACT The aim of this study was to evaluate the effects of potassium and sodium fertilization (control: 4.5kmol.ha-1 of KCl and 4.5kmol.ha-1 of NaCl), and water regimes (100% and 63% rainfall with artificial exclusion) on wood and briquette density in Eucalyptus grandis trees at 5 years, and the application of X-ray densitometry on the quality of briquettes. Tree trunk samples were obtained to determine wood density, production and briquette density by X-ray densitometry and stereometric. The artificial exclusion of rainwater promoted an increase in wood density, and the fertilization treatments versus water availability did not affect the density of briquettes. The method used to determine the briquette density influenced the average values, with an increase of 12% in the X-ray densitometry to the stereometric.