A comparative study of sensor technologies measuring wind-tree dynamics

As climate change intensifies and alters weather patterns, windstorms are expected to increase both in frequency and intensity. Even at present levels, wind is the leading cause of damage to individual trees and entire forests. Many research methods have been developed and many technologies utilized to understand wind-tree dynamics. But yet, there are still no standard practices for monitoring and quantifying wind effects on trees. This study compares multiple different sensor technologies that have been used in previous studies to record and analyze tree motion in response to wind. Six sensors attached to three living Pinus spp. trees were tested through non-destructive pulling tests, pull-and-release tests, and ambient free-sway conditions. The sensors chosen represented a range of sensitivity, resolution, and market cost. The signals recorded during field tests by each sensor were first processed, then the frequencies and damping ratios calculated and compared. Results showed that the measured response of the tree to excitation is highly dependent on sensor sensitivity and resolution. At low wind speeds, this could result in errors or missing data. Sensor characteristics play an important role in the way study results can be perceived, highlighting the importance of choosing a reliable sensor and utilizing it in a consistent manner. In the future, this study could be replicated to compare other sensors not tested here, or on different tree species with a decurrent growth habit. With further exploration, a standardized set of best practices could be proposed by the scientific community and adopted by practitioners to achieve the best results in understanding wind-tree dynamics.