Résumé
Considerable areas of forest plantations of fast-growing of eucalyptus in Brazil and in other regions of the world are 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 growth of the trunk of Eucalyptus grandis trees for 24 months, evaluating the reduction in rainfall and potassium and sodium nutrition. The treatments were defined by two water treatments (100 and 66% of rainfall, with artificial exclusion with polyethylene sheeting) and three types of nutrition: K (K - 4.5 kmol/ha), Na (Na - 4.5 kmol/ha) and control. 54 eucalyptus trees per treatment were selected and installed with a dendrometric band at DAP height. The results showed the effect of the climatic seasonality in the increase in diameter of the trunk of the tree, with maximum and minimum periods of growth rate and the cambial meristem and, therefore, the measurement of the diameter of the trunk with the dendrometers indicate that the response to a given climatic event is expressed after the period of 15, 30 and up to 45 days. Tree treatments with 100% of rainfall had higher cumulative growth, as well as treatments with application K. The results may be used as subsidies for the adoption of silvicultural practices in forest plantations in areas with water stress, as well as replacement part of K by Na.