Reproducibility of Stress Wave and Electrical Resistivity Tomography for Tree Assessment (original) (raw)

Non-Destructive Assessment of Living Trees by using Electric Resistive Tomography

2020

Electric Resistive Tomography is one of the latest procedures in the assessment of living trees. There is a growing interest regarding this measurement method yet despite the presence of such measuring devices on the market, this method, unlike acoustic assessment techniques for trees, is far from being fully developed. The devices available on the market analyze only the nature of resistivity of the device, but do not take into account the phase character of the measurements. In addition to measurement information, this paper presents several results regarding fixed impedance tomography. The experience gained here is to be used for further research. Key-Words: non-destructive assessment of materials, assessment of living trees, Electrical Impedance Tomography

Combining Sonic and Electrical Impedance Tomography for the Non-destructive Testing of Trees

2008

For the non-destructive testing of standing trees sonic tomography is currently the “state-of-the-art” in many parts of the world. The most significant step forward in this technology in the recent years is the reduction in hardware requirements – by using an electronic hammer the number of sensors can be halved. Especially in large trees this increases the accuracy of the measurements. Although in the majority of cases the results are correct and easy to interpret, some limits remain. To overcome the limits of sonic tomography our research group has been adapting electrical impedance tomography (EIT) from geoelectrics to be used for trees since 1998 [4]. Among other properties, the system allows the detection of early stages of decay, wet wood and different types of heartwood [9]. Since 2004 new reconstruction algorithms for the electric impedance tomography have improved the results by using the exact shape of the measured cross-section of the tree. To achieve this, modern inversi...

A new tomographic device for the non - destructive testing of trees

A new device allows the non - destructive inspection of standing trees for cracks, cavities, and rot. It is based on the simultaneous measurement of the time of transmission of stress waves by several sensors arranged around the stem. The system was extensively tested by comparison of the tomogram with either the cross - section of the tree cut after the measurement, or with data from penetrometers or increment cores obtained in the same plane. The border of cavities is identified to the nearest cm, whereas the with of cracks in the tomogram depends on the position of the sensors around the stem. Rots are identified as soon as the wood is sufficiently deteriorated to reduce the velocity of sound. This system may become a valuable tool for hazard tree inspection, evaluation, and management.

Adapted VTA and SIA method in tree static assessment with use of resistography

Periodicum Biologorum

Background and Purpose: This paper introduces a method for assessment of static safety by using the combination of adapted VTA and SIA methods and a resistograph. The aim is to assess the static as reliably as possible and without the need for expensive equipment. The purpose of this paper is to propose amethod for the static assessment which could be applied in practice in the future. Materials and Methods: Seven trees in the Botanical Garden of the Faculty of Science (University of Zagreb) were selected for the assessment of vitality and static safety. It has been detected that those trees were affected by possible indicators of decreased vitality, such as fungi fruiting bodies on the root collar or trunk, dead branches, growthmalformations, burrs, dead bark etc. The selected trees were: Fagus sylvatica L. »Purpurea Tricolor«, Fraxinus pennsylvanica Marshall, Acer pseudoplatanus L. »Leopoldii«, Fagus grandifolia Ehrh., Quercus petraea L., Quercus phellos L. and Salix alba L. The s...