Understanding the dynamic properties of trees using the motions constructed from multi-beam flash light detection and ranging measurements

• Published in: Journal of the Royal Society interface 2022-08, Vol.19 (193), p.20220319-20220319
• Main Authors: Chau, Wai Yi, Loong, Cheng Ning, Wang, Yu-Hsing, Chiu, Siu-Wai, Tan, Tun Jian, Wu, Jimmy, Leung, Mei Ling, Tan, Pin Siang, Ooi, Ghee Leng
• Format: Article
• Language: English
• Subjects: Life Sciences–Engineering interface; Motion; Trees - physiology; Vibration
• ISSN: 1742-5662; 1742-5689; 1742-5662
• DOI: 10.1098/rsif.2022.0319

Measuring the three-dimensional motion of trees at every position remains challenging as it requires dynamic measurement technology with sufficient spatial and temporal resolution. Consequently, this study explores the use of a novel multi-beam flash light detection and ranging (LiDAR) sensor to tackle such a sensing barrier. A framework is proposed to record tree vibrations, to construct the motions of tree skeletons from the point-cloud frames recorded by the LiDAR sensor and to derive the dynamic properties of trees. The feasibility of the framework is justified through measurement on a under pull-and-release tests. The relative differences for the first two modal frequencies between the LiDAR and linear variable differential transformer measurements in the displacement Fourier spectra are 0.1% and 2.5%, respectively. The framework is further adopted to study the dynamic response of different trees subjected to typhoons, including a , three trees, , a , a and a . Results suggest that broadleaved trees might exhibit vibration in a wide frequency band, whereas the coniferous trees could follow a distinct dominant frequency.