Preliminary experiments and verification of controlled pulling tests for tree stability assessments in Mediterranean urban areas

Sani, L.; Lisci, Riccardo; Moschi, M.; Sarri, Daniele; Rimediotti, Marco; Vieri, Marco; Tofanelli, Sergio

doi:10.1016/j.biosystemseng.2012.04.004

Cited by 33 publications

(27 citation statements)

References 15 publications

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“…Since O 1,j was always very close to zero and did not increase after the impact of the highest wind loads, it is assumed that the root plate resisted all wind loads. In the previous quasi-static tree pulling studies [27,28], root plate inclination less than a benchmark of 0.25 • was considered to be sufficiently low to stay in the elastic deformation range below the limit of proportionality in stem bending ( Figure 10) and to prevent primary failure in the roots. If this benchmark is transferred to this study, one can assume that the tree response at the stem base was always in the range of elastic deformation and did not cause any plastic deformation in the roots.…”

Section: Dynamic Time Warpingmentioning

confidence: 99%

“…The mode of the 20 values is taken as the maximum turning moment for the hour [26].A further field of application for tree pulling tests is the non-destructive inspection of urban tree stability against wind loading. This kind of pulling test is used as a diagnostic technique in the assessment of the wind load bearing capacity of trees without causing damage to them [27,28]. The results from these tests are extrapolated to determine CWS.…”

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confidence: 99%

“…Idealized dependence of tree response at stem base to wind loading. The relationship is based on examples provided in previous studies[24,27,28].…”

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confidence: 99%

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Assessment of the Response of a Scots Pine Tree to Effective Wind Loading

Schindler

Kolbe

2020

Forests

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The parameterization of hybrid-mechanistic storm damage models is largely based on the results of tree pulling tests. The tree pulling tests are used for imitating the quasi-static wind load associated with the mean wind speed. The combined effect of dynamic and quasi-static wind loads associated with wind load maxima is considered by either linearly increasing the quasi-static wind load by a gust factor or by using a turning moment coefficient determined from the relationship between maxima of wind-induced tree response and wind speed. To improve the joint use of information on dynamic and quasi-static wind loading, we present a new method that uses the coupled components of momentum flux time series and time series of stem orientation of a plantation-grown Scots pine tree. First, non-oscillatory tree motion components, which respond to wind excitation, are isolated from oscillatory components that are not coupled to the wind. The non-oscillatory components are detected by applying a sequence of time series decomposition methods including bi-orthogonal decomposition and singular spectrum analysis. Then, the wind-excited tree response components are subjected to dynamic time warping, which maximizes the coincidence between the processed data. The strong coincidence of the time-warped data allows for the estimation of the wind-induced tree response as a function of the effective wind load using simple linear regression. The slope of the regression line represents the rate of change in the tree response as the effective wind load changes. Because of the strength of the relationship, we argue that the method described is an improvement for the analysis of storm damage in forests and to individual trees.

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Section: Dynamic Time Warpingmentioning

confidence: 99%

mentioning

confidence: 99%

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Assessment of the Response of a Scots Pine Tree to Effective Wind Loading

Schindler

Kolbe

2020

Forests

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“…In cities, internal decay cause tree or tree parts to fall and constitute a significant hazard to people and property (Sani et al 2012). Accordingly, numerous studies have focused on the development of analysis tools that allow detection of decay in trees.…”

Section: Introductionmentioning

confidence: 99%

Interference from Knots, Wave Propagation Direction, and Effect of Juvenile and Reaction Wood on Velocities in Ultrasound Tomography

Palma¹,

Gonçalves²,

Trinca³

et al. 2018

BioResources

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Acoustic tomography is based on the velocity variation inside the inspected element. However, wood is heterogeneous and anisotropic, which causes natural velocity variations. In wood, the great challenge to apply this technology is to interpret and differentiate the natural variations of the material from those caused by deterioration. This study aimed to evaluate the interference caused by knots, the wave propagation direction, and the effect of juvenile and reaction wood on the velocities determined via ultrasonic tomography. The tests were performed using 40 disks of Pinus elliottii. From the results it was concluded that intrinsic orthotropy of the wood was reflected in the wave propagation on the disks with radial velocities greater than the tangential ones, higher velocities in the knot zones, and different velocities in the zones of compression and opposition wood. In the measurements using the diffraction mesh, the edge velocities (tangential direction with the maximum angle from the radial direction) were always lower than all of the other velocities in the disk. More significant variations in the velocity were obtained in the juvenile wood. These results contribute to quantifying some interferences associated with tomography images, such that the misinterpretation can be minimized.

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“…destructive tree-pulling test, from which an information on the critical force was obtained. Subsequently, the second experiment was a non-destructive test to tree B in which the pulling was carried out with a force less in magnitude than the previous experiment, so as to not cause the tree to enter the plastic region of deformation [6]. From the second experiment, a defl ection graph resulted from the applied force could be obtained, and further calculation of its slope would allow us to get the value of fl exibility [9] of sengon trees.…”

Section: Sengon Treeand Experimental Methodsmentioning

confidence: 99%

Validation of strength and flexibility of sengon (Paraserianthes falcataria) by experimental tree-pulling test and numerical simulation

Nirbito¹,

Ardianto

Ramadhan

et al. 2019

J Appl Eng Science

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Stability assessment of trees is considered important in urban areas to detect possible occurrence of tree failures that often result in disastrous damages. Tree-pulling test is a low-cost, well-known method that has been practiced by researchers and practitioners alike from several decades ago. From the method, a number of parameters related to the physical characteristics of the tree can be further derived. However, the tree-pulling test has only been widely practiced mostly for tree species in subtropical region, such as pines, spruces, and birches. In this paper, a tree-pulling test on sengon (Paraserianthes falcataria), a tree native to Indonesia is reported. Such a study is imperative as sengon is among the most commonly planted tree species in the urban areas of Indonesia and there have been alarming reports of falling sengon trees. Two kinds of tree-pulling test are conducted. i.e. destructive and non-destructive. From these experiments, the critical force that results in a breakage as well as the fl exibility of sengonare obtained. Numerical simulations are also carried out. The results arecompared and they show a good fi t to the experimental data, justifying the assumed linearly elastic behavior.

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Preliminary experiments and verification of controlled pulling tests for tree stability assessments in Mediterranean urban areas

Cited by 33 publications

References 15 publications

Assessment of the Response of a Scots Pine Tree to Effective Wind Loading

Assessment of the Response of a Scots Pine Tree to Effective Wind Loading

Interference from Knots, Wave Propagation Direction, and Effect of Juvenile and Reaction Wood on Velocities in Ultrasound Tomography

Validation of strength and flexibility of sengon (Paraserianthes falcataria) by experimental tree-pulling test and numerical simulation

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