Resumo. This work was developed in order to evaluate the mechanical breakage of trees and its relation to the dendrometric characteristics, the wood specific gravity and bending (MOE, MOR and work to maximum load) in order to select clones more tolerant to wind action. The mechanical resistance of the trees to break was determined by the simulation of the effect of wind on them, getting the strength to break the trees. Ten clones of Eucalyptus urophylla x Eucalyptus grandis hybrid with 30 and 35 months in forest plantations in the lowlands were evaluated. The average force to break the trees was 79.00 kgf, the average height of 2.99 m. The average wood density was 0.40 g / cm³. MOE, MOR and work to maximum load in static bending tests were equal to 60,965 kgf / cm², 544 kgf / cm² and10 J, respectively. The CNB017 showed the best results in the resistance of trees to break test and in the physical and mechanical parameters evaluated, being con sidered the most suitable clone for the areas subjected to wind breakage of trees.