The applicability of a dynamic mechanical analyzer (DMA) in determining the modulus of elasticity (MOE) of 2.5-year-old transgenic aspen (Populus tremuloides Michx.) was investigated. Fifty sample trees with diameters ranging from 8 to 14 mm were harvested from the greenhouse. The trees were from one wild-type group and three transgenic groups. DMA was used in static bending mode to determine the MOE of samples soaked in two different plasticizers: water and ethylene glycol. In addition, dynamic MOE by a nondestructive method and static MOE by a micromechanical test were determined. Results showed that DMA measurements were accurate in showing significant differences between the genetic groups. Although notably higher MOE values were obtained for dynamic MOE and static MOE compared with the DMA measurements, the trend of elastic moduli change across the genetic groups was the same for all three methods.