Detection of electric resistivity tomography and evaluation of the sapwood-heartwood demarcation in three Asia Gymnosperm species

Lin, Cheng-Jung; Chung, Chi-Jui; Yang, Tsung Han; Lin, Fengyi

doi:10.14214/sf.440

Cited by 19 publications

(16 citation statements)

References 15 publications

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“…The theory that explains the strong moisture dependency of electrical resistivity of wood was proposed in the 1950s and has been reviewed extensively since then (Hearle 1953;Skaar 1988). In general, the moisture content of sapwood is significantly higher than that of heartwood in most species, resulting in lower electrical resistivity in sapwood than that in heartwood (Skaar 1988;Bieker and Rust 2010b;Lin et al, 2012); Some tree species (Quercus robur L.) are exceptions (Bieker and Rust 2010a).…”

Section: Theory and Methods Of S-h Differentiation Using Ertmentioning

confidence: 99%

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Quantifying sapwood width for three Australian native species using electrical resistivity tomography

et al. 2015

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Section: Theory and Methods Of S-h Differentiation Using Ertmentioning

confidence: 99%

“…Third, ERT is reasonably portable and efficient to use. It only takes 15 to 30 min to finish one measurement per tree (Bieker and Rust 2010b;Lin et al, 2012;Guyot et al, 2013). Therefore, it is suitable for measurement on a large number of trees.…”

Section: Advantages and Limitations Of Ert Techniquementioning

confidence: 99%

Quantifying sapwood width for three Australian native species using electrical resistivity tomography

et al. 2015

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“…With the development of finite element technology, it is combined with resistance imaging to study the electrical resistance of standing trees [12]. With the continuous development of ERT (Electrical Resistance Tomography) and computer technology, German researchers have developed a tree-resistance tomography imager called Picus Tree-Tronic, a widely used detection instrument specifically for the evaluation of internal decay [13] or detecting heartwood and sapwood of trees [14,15]. Following this, many researchers have conducted studies based on non-destructive testing to examine the effects of species, density, decay, and electrolyte content in the accurate determination of electrical resistance non-destructive testing technique [13,16].…”

Section: Introductionmentioning

confidence: 99%

Investigations on the Effects of Seasonal Temperature Changes on the Electrical Resistance of Living Trees

Xiaoquan

Wang

Shi

et al. 2018

Forests

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In order to use the electrical resistance method to accurately and timely detect and evaluate the internal decay defects of living trees, the effects of the seasonal temperature and moisture content on the electrical resistance of standing trees were investigated. At the Northeast Forestry University Experimental Forest Farm, Harbin, Heilongjiang Province of China, Populus simonii Populus simonii Carr. and Larix gmelinii (Rupr.) Rupr. were selected as the objects and the electrical resistance of standing trees was tested through different seasons from December 2016 to December 2017. Meanwhile, the effects of changes in the seasonal temperatures (−20 to −10 • C, −10 to −5 • C, −5 to 0 • C, 0 to 5 • C, 5 to 10 • C, 10 to 15 • C, 15 to 25 • C) as well as changes in the moisture content (MC) (Populus simonii, MC ≥ 103%; Larix gmelinii, MC ≥ 77.5%) on the electrical resistance in the cross-sections of living trees were studied. The influence of temperature at different moisture contents, the moisture content at different temperatures, and their combined effects on electrical resistance were analyzed, following which a regression model was also established. The obtained results indicated that ambient temperature had a significant effect on the average value of electrical resistance in the cross-section of living trees when temperatures were below the freezing point. There was a sudden discontinuity near the freezing point, and logR (logarithm value of electrical resistance) in the cross-sections of sound trees and decayed trees changed in a similar trend with variations in the temperature. While the effect of moisture content on logR in the cross-sections of threes was insignificant at different temperatures because of the moisture content above FSP (fiber saturation point). It indicated that the temperature and moisture content had interactive effects on logR in the cross-sections. The binary linear regression model between moisture content, temperature, and logR was highly fitted with a correlation coefficient (R 2 ) higher than 0.8. The outcome of this investigation indicates that when non-destructive testing is performed on living trees using electrical resistance at different seasonal temperatures, the measured results need to consider both the temperature and moisture content. For practical work, it is not recommended to consider testing living trees near the freezing point temperature using the electrical resistive tomography. Below the freezing point, the electrical resistance changes with temperature greatly relative to the normal temperature. Therefore, when performing the detection of electrical resistance, it is necessary to calibrate the effects of temperature

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“…Since the first experiments by Just and Jacobs (1998), there have been several applications of this technique, for example, to detect decay Bieker and Rust 2010a), red heartwood in beech Hanskötter 2004) and in wild service tree (Weihs 2001), and brown heartwood or the early stages of white rot in ash (Weihs et al 2005;Bieker et al 2010, respectively). It can also be used to determine the exact sapwood area in various species (Bieker and Rust 2010b;Lin et al 2012). Rust and Göcke (2007) combined electrical impedance tomography and sonic tomography to create the PiCUS Treetonic system.…”

Section: Introductionmentioning

confidence: 99%

Detecting the presence of red heart in beech (Fagus sylvatica) using electrical voltage and resistance measurements

2017

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a discoloration of their contents (Panshin and DeZeuw 1980). It is almost ubiquitous in older trees at felling age, but often affects younger specimens too. Healthy red heartwood is mostly considered a visual defect only, but, since beech is most often used in the furniture industry and interior design, red heart causes a major decrease in the perceived value, and leads to a serious drop in the retail price of beech wood (Molnar et al. 2001;Hapla and Ohnesorge 2005).There are several forms of red heart, all of which occur in beech wood. According to the characterisation by Sachsse (1991), they can be classified as red heartwood with round borders and a partly cloudy appearance on the cross-section, wounded heartwood with a small spatial extent, splashing heartwood (or dotty red heart) with jagged borders, and abnormal heartwood with black borders attacked by bacteria. In either case, the borders of red heart do not follow the annual ring boundaries. Figure 1 shows the first type, immediately after felling. In terms of its longitudinal expansion, it is most often spindle-like, but it may also be cone or upside-down cone shaped, or irregular. Red heart can also be classified as healthy or diseased, based on whether or not it has been attacked by fungi, and, as a result, they suffered some strength loss (Rumpf and Biro 2003;Wernsdörfer et al. 2005).Beech red heart has generated considerable research interest over the past decades. Wernsdörfer et al. (2005) provided a very detailed overview of the work done up to that point. Knoke (2002) provided a thorough review of the publications on heartwood formation, and concluded that reducing the amount of discolored timber is possible only based on information about the recent formation of red heartwood. He lamented the fact that non-destructive methods are not yet far enough advanced to provide information on early heartwood formation. AbstractRed heart is one of the most important visual defects in beech wood. Its detection is difficult, since its mechanical characteristics do not differ significantly from sound wood. However, its electric conductivity is different, which offers an opportunity for detecting beech red heart. Initial measurements using a 24-channel impedance tomograph were very efficient in detecting red heart due to its significantly lower electric resistance. High conductivity regions on the resistance map corresponded to the size and shape of the red heart. An 8-detector setup was investigated in a laboratory setting to establish the best electrode arrangement to develop a simple and reliable on-site detection method. On-site measurements, using only four electrodes, proved to be highly reliable to detect the presence of red heart in beech trees of 40-60 cm diameter. In the meantime, the method did not seem capable of determining the extent of red heart. The diameter of the tree was found to have very little effect on the measured voltage. Therefore, there is no need for diameter-correction in the examined diameter range.

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Detection of electric resistivity tomography and evaluation of the sapwood-heartwood demarcation in three Asia Gymnosperm species

Cited by 19 publications

References 15 publications

Quantifying sapwood width for three Australian native species using electrical resistivity tomography

Quantifying sapwood width for three Australian native species using electrical resistivity tomography

Investigations on the Effects of Seasonal Temperature Changes on the Electrical Resistance of Living Trees

Detecting the presence of red heart in beech (Fagus sylvatica) using electrical voltage and resistance measurements

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