Can sonic tomography predict loss in load-bearing capacity for trees with internal defects? A comparison of sonic tomograms with destructive measurements

Burcham, Daniel C.; Brazee, Nicholas J.; Marra, Robert E.; Kane, Brian

doi:10.1007/s00468-018-01808-z

Cited by 19 publications

(20 citation statements)

References 17 publications

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“…Although desirable to increase the accuracy of the estimate, it is clear that weighing the contribution of tomographic pixels to the load-bearing capacity with the stress wave velocity, as described by [19], would not be justified. Another point of debate is the best color threshold to use to discriminate between intact wood and decay or cavities [36,37]. Based on our experience, we decided not to include green areas in the decay/cavity category.…”

Section: Discussionmentioning

confidence: 99%

Do Sonic Tomography and Static Load Tests Yield Comparable Values of Load-Bearing Capacity?

Rust,

Detter

2024

Forests

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We tested the hypothesis that the loss of load-bearing capacity, as estimated by means of static load tests and from sonic tomography, is comparable. This is of practical importance for arborists when they have to assess results reported by different consultants or when they have to choose between applying one of these two methods in a specific case. A total of 59 trees, primarily Fagus sylvatica and Quercus robur, were subjected to static load tests and sonic tomography. The pulling test method yielded the residual stiffness of the stem at every position tested with a strain sensor as an intermediate quality parameter used to merely validate the actual estimations of safety against fracture. Based on the shape of the parts of the stem cross-section that are considered load bearing, sonic tomograms can be further processed in order to assess the loss of load-bearing capacity from defects like decay. We analyzed the correlation of these biomechanically equivalent parameters. This was only the case to a very limited extent. Sonic tomography and static load tests cannot replace each other, but they can complement each other.

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Section: Discussionmentioning

confidence: 99%

Do Sonic Tomography and Static Load Tests Yield Comparable Values of Load-Bearing Capacity?

Rust,

Detter

2024

Forests

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“…We explained this to assessors prior to the field study. After the field study, we computed the loss in section modulus due to decay (ZLOSS) from each sonic tomogram following the method of [32]. proportions of the total cross-sectional area.…”

Section: Methodsmentioning

confidence: 99%

Assessing the Likelihood of Failure Due to Stem Decay Using Different Assessment Techniques

Okun¹,

Brazee²,

Clark³

et al. 2023

Preprint

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Arborists commonly investigate the extent of stem decay to assess the likelihood of stem failure when conducting tree risk assessments. Studies have shown that (i) arborists can sometimes judge the extent of internal decay based on external signs; (ii) sophisticated tools can reliably illustrate the extent of internal decay; and (iii) assessing components of tree risk can be highly subjective. We recruited 18 experienced tree risk assessors who held the International Society of Arboriculture’s Tree Risk Assessment Qualification (TRAQ) to assess the likelihood of stem failure due to decay after each of 5 consecutive assessments on 30 individuals of 2 genera. Five assessment techniques, in stepwise order, were 1) visual, 2) sounding the trunk with a mallet, 3) viewing a scaled diagram of the cross-section that revealed sound and decayed wood ascertained from resistance drilling, 4) viewing sonic and electrical resistance tomograms, and 5) consulting with a peer. For each technique, assessors assigned two or more likelihood of failure ratings (LoFRs) for at least 83% of trees, which were proportionally greatest after assessors viewed tomograms; the proportions did not differ among the other four assessment techniques. Covariates that influenced the distribution of LoFRs included percent of the cross-section that was decayed, and assessors’ experience using resistance drilling devices and tomography in regular practice. Practitioners should be aware that disagreement on the likelihood of tree failure exists even among experienced arborists.

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“…This noted, some defects have received more empirical scrutiny than others. Many studies have investigated how well practitioners can assess the presence, extent, and location of decay [43][44][45][46]; fewer have explored the degree to which decay increases the likelihood of failure [19,47]. In this study, the presence of decay was associated with a greater proportion of branch and whole tree failures (Figure 3), but the data from Koeser et al [19] did not align with this, which is a reminder that the presence of even a severe defect does not always induce failure.…”

Section: Defect Analysismentioning

confidence: 99%

The Impact of Visual Defects and Neighboring Trees on Wind-Related Tree Failures

Nelson

Klein

Koeser

et al. 2022

Forests

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Urban trees are often more sun- and wind-exposed than their forest-grown counterparts. These environmental differences can impact how many species grow–impacting trunk taper, crown spread, branch architecture, and other aspects of tree form. Given these differences, windthrow models derived from traditional forest production data sources may not be appropriate for urban forest management. Additionally, visual abnormalities historically labeled as “defects” in timber production, may not have a significant impact on tree failure potential. In this study, we look at urban tree failures associated with Hurricane Irma in Tampa, Florida, USA. We used spatial analysis to determine if patterns of failure existed among our inventoried trees. We also looked at risk assessment data to determine which visual defects were the most common and the most likely to be associated with branch or whole-tree failure. Results indicate that there was no spatial pattern associated with the observed tree failures–trees failed or withstood the storm as individuals. While some defects like decay and dead wood were associated with increased tree failure, other defects such as weak branch unions and poor branch architecture were less problematic.

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Can sonic tomography predict loss in load-bearing capacity for trees with internal defects? A comparison of sonic tomograms with destructive measurements

Cited by 19 publications

References 17 publications

Do Sonic Tomography and Static Load Tests Yield Comparable Values of Load-Bearing Capacity?

Do Sonic Tomography and Static Load Tests Yield Comparable Values of Load-Bearing Capacity?

Assessing the Likelihood of Failure Due to Stem Decay Using Different Assessment Techniques

The Impact of Visual Defects and Neighboring Trees on Wind-Related Tree Failures

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