This study aimed at evaluating thermal modification in mechanical properties of Corymbia citriodora and Eucalyptus saligna woods compared with a control. To do so, three samples of each species were selected, with approximately 40 years, which had the first two three-meter long logs removed. Wood thermal modification was done through final temperatures of 140 °C, 160 °C e 180 °C for 2.5 hours, and the control as well, using a forced air circulation greenhouse. Mechanical properties tests consisted of maximum impact resistance evaluation, static bending, and fiber parallel compression. Generally, results showed that thermal modification increases wood resistance up to a certain point and reduces in the highest temperature.