Seasonal variations of oscillation and vibration parameters of Acer platanoides

This article describes an investigation into the seasonal variations of frequency, damping ratio and amplitude of swaying and vibration of Norway maple Acer platanoides L. The study was carried through a series of pull and release experiments in situ and on branches in the laboratory using an artificial air flow. It was found that foliated trees had a natural sway frequency that was on average 1.6 +/- 0.2 times greater than in the out-of-leaf state. In contrast, the damping ratio of maple increased by 1.5 +/- 0.3 times in the summer period. The stem swaying initiated vibrations, i.e. elastic wave, in the roots with frequencies in the range of 45-50 Hz. Laboratory tests showed that the vibration amplitude of branches depended linearly on leaf mass for an air flow velocity of 1.94 m/s.