This study summarises the test results of Pannónia poplar (Populus × euramericana cv.
Pannónia) originating from three plantation sites in Győr-Moson-Sopron County in the Western
Transdanubia region of Hungary: Újrónafő 11G, Győr 540B, and Kapuvár 35A. The research
primarily aimed to clarify the characteristics of radial growth depending on the plantation site and to
predict the selected physical and mechanical properties of the xylem. Measuring the time-of-flight
(TOF) in trees was performed with a non-destructive test technique using a “Fakopp” TreeSonic
device. The stress wave velocity (SWV) values calculated from TOF data are significant in estimating
the dynamic modulus of elasticity (MOE) of the xylem and, therefore, in the prediction of timber
suitability for structural applications. During the on-site measurements, 50 trees – as random samples
from every site – were investigated to determine the diameter at breast height (DBH) and the stress
wave velocity in sapwood parallel to the grain. In addition to the non-destructive measurements, the
laboratory analysis of the xylem from harvested logs (three logs per site, random sample) was also
performed to determine the radial growth rate and density. The one-way ANOVA results revealed
significant differences in SWV values between certain plantation groups. The difference between the
average values of young and old plantations is 136.8 m/s, which is a significant difference. Similar
findings occurred for the middle-aged and old plantation trees. The average values of the young and
the middle-aged trees can be considered the same at the 0.05 level of significance. We also established
that the trees in the young (22 years old) plantation site, Újrónafő 11G, planted with the closest
spacing (3 m × 4 m), had the lowest average diameter of breast height naturally and showed the
highest average value of SWV. Nevertheless, the sap- and heartwood samples from this plantation site
had the highest average density values in a normal climate; therefore, the highest dynamic modulus of
elasticity of the xylem can be expected in logs originating from this plantation site
