Applying precision triaxial accelerometer to monitor branch sway of an urban tree in a tropical cyclone

Lee, Louis S.H.; Jim, Chi Yung

doi:10.1016/j.landurbplan.2018.05.028

Cited by 10 publications

(12 citation statements)

References 38 publications

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“…With a special concern on hurricanes in the southeastern US, tree species are the dominant factor to the high survival rate in wind, and a statistical comparison demonstrated that tree species with higher wood density had a greater chance to survive under strong wind. Lee and Jim measured the sway behavior of one broadleaf deciduous flame tree during a tropical cyclone in terms of sway magnitude, sway amplitude, and in-situ wind properties in Hong Kong [57]. A combination of triaxial accelerometer and sonic anemometer and the comparison of inter-branch sway behavior denoted that the mean sway magnitude (SM MEAN ) is an important parameter to analyze tree-wind interactions in summer, especially during typhoon seasons.…”

Section: Selection Of Study Periodmentioning

confidence: 99%

“…Experimenting with high wind events is a widely used approach to investigate responses of trees under wind loading, which is quick and easy to set up. As stated in Section 3.1.3, high wind events occur mainly in summer, and most of the studies focused on tropical cyclone cases [55][56][57] affecting the tree movement. In autumn and winter, the responses of several deciduous tree species under windstorms were also investigated [24], showcasing that more than 60% of trees and branches fall in Lisbon during cold seasons.…”

Section: High Wind Eventsmentioning

confidence: 99%

“…During the in-situ measurement and simulation modeling, various sensors and equipment have been designed to measure the displacement of trees and wind behavior. For non-destructive technologies to investigate the mechanism of tree-wind interactions, the components of tilt measurement sensors, i.e., triaxial accelerometer [57,61] and clinometers [31,33,49], are introduced. Other instruments are also used for tilt measurement, including laser Doppler interferometers [28] and sonic anemometers [40].…”

Section: Instruments For Tree Behavior Measurementmentioning

confidence: 99%

“…The sampling frequency is usually 20 Hz. James et al [26] used a triaxial accelerometer to measure longitudinal motion (X-axis), lateral motion (Y-axis), and vertical motion (Z-axis), to assess the branch sway of a flame tree in Hong Kong [57]. This tree motion sensor (TMS) has an angular sensitivity at 0.01°, a sampling frequency of 20 Hz, and a response time of 400 ms. Clinometers: Clinometers (Figure 2) are instruments used for measuring angles of tilt to gravity's direction.…”

Section: Tilt Measurementmentioning

confidence: 99%

“…Fourier Transform was used to determine the frequency range of Scots pine trees, and wavelet analysis was used to analyze coherent structures in a turbulent flow. Lee and Jim [57] used wavelet analysis (the time-frequencybased technique) and F-test (the time-space-based technique) together to monitor the sway behavior of a broadleaf flame tree.…”

Section: A Combination Of Multiple Analysismentioning

confidence: 99%

See 4 more Smart Citations

A Review of Dynamic Tree Behaviors: Measurement Methods on Tree Sway, Tree Tilt, and Root–Plate Movement

Yang

Hui

Abbas

et al. 2021

Forests

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Urban forest ecosystems are being developed to provide various environmental services (e.g., the preservation of urban trees) to urban inhabitants. However, some trees are deteriorated asymptomatically without exhibiting an early sign of tree displacement, which results in a higher vulnerability under dynamic wind loads, especially during typhoon seasons, in the subtropical and tropical regions. As such, it is important to understand the tilt and sway behaviors of trees to cope up with the probability of tree failure and to improve the efficacy of tree management. Tree behaviors under wind loads have been broadly reviewed in the past literature, yet thorough discussions on the measurement methods for tree displacement and its analysis of broadleaf specimens are lacking. To understand the behavioral pattern of both broadleaf and conifer species, this paper presents a detailed review of sway behavior analysis from the perspectives of the aerial parts of the individual tree, including tree stem, canopy, and trunk, alongside a highlighted focus on the root–plate movement amid the soil-root system. The analytical approaches associated with the time-space domain and the time-frequency domain are being introduced. In addition to the review of dynamic tree behaviors, an integrated tree monitoring framework based on geographic information systems (GIS) to detect and visualize the extent of tree displacement using smart sensing technology (SST) is introduced. The monitoring system aims to establish an early warning indicator system for monitoring the displacement angles of trees over the territory of Hong Kong’s urban landscape. This pilot study highlights the importance of the monitoring system at an operational scale to be applicable in the urban areas showcasing the practical use of the Internet of Things (IoT) with an in-depth understanding of the wind-load effect toward the urban trees in the tropical and subtropical cities.

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Section: Selection Of Study Periodmentioning

confidence: 99%

Section: High Wind Eventsmentioning

confidence: 99%