Résumé
Expressive area of forest plantations fast-growing of eucalyptus in Brazil and in other regions of the world is under the influence of climate change, water stress and low soil fertility, affecting the growth and the quality of the wood from the trees. This study aimed to evaluate the apparent density at 12% relative humidity of the wood of Eucalyptus grandis trees with 12, 24 and 36 months, with reduced rainfall and nutrition K and Na. The treatments were defined by two water regimes (100% and 66% of rainfall, with artificial reduction with polyethylene sheeting) and three types of nutrition: K (K - 4.5 kmol/ha), N (Na - 4.5 kmol/ha) and control. The apparent density of the samples of diameter at breast height was determined by densitometry profile from digital images of rays X. The results indicated a significant difference in nutrition treatments and water availability in relation to the density of the wood. The radial apparent density profiles showed higher differences in the wood from the third year of evaluation. Digital images of the wood obtained by X-rays allowed to analyze the variation of the apparent density of the wood. Work results may be used as subsidies for the adoption of silvicultural practices in forest plantations in areas with water stress and/or affected by climate change as well as the partial replacement of K by Na.