Measuring wood quality in standing trees--a review

Analysis of a tree ring is the primary method for determining the growth and age of a tree. In a microdestructive tree-ring measurement system, the tree under test is drilled with a microdrill at a constant rotating speed to detect the difference in density between the early and late wood, thereby realizing a microdestructive measurement of the tree-ring. The measurement system comprises a microdrill with a diameter of 3 mm, mechanical transmission, direct current (DC) servomotor, stepper motor, and control and detection circuit. The DC servomotor and stepper motor realize rotation and translation of the microdrill, respectively, through mechanical transmission. When the microdrill rotates and drills into the tree, the control and detection circuit samples and acquires the armature current of the DC servomotor, which is proportional to the resistance encountered by the drill bit and reflects the change in the density of the tree. The tree-ring number can be obtained by filtering the sampled original signals of the armature current using a finite impulse response (FIR) filtering algorithm. The annual rings of larch and fir tree discs were measured and tested using the designed system. It was observed that the average annual ring measurement accuracy of the larch discs reached 95.28%, while that of the fir discs was 84.16%. The diameter of the drill hole in the trunk was less than 3 mm after measuring the living wood, thereby achieving a microdestructive measurement of the tree-ring.

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“…The results are listed in Tables 1 and 2. The measurement accuracy (MA) in the table is calculated by Equation (13).…”

Section: Test Resultsmentioning

confidence: 99%

“…The detection of the tree density can be realized using this stress wave technique. However, this detection equipment has relatively low detection accuracy, and it can only identify the rot and holes present in the tree, but not the annual rings or other small density changes [12,13].…”

Section: Introductionmentioning

confidence: 99%

Design and Test of a Microdestructive Tree-Ring Measurement System

Zheng

Liang

et al. 2020

Sensors

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“…Legg and Bradley [47] provided a thorough review of the literature concerning the stiffness of trees, logs and lumber. Acoustic methodology was reviewed by [46,48].…”

Section: Methods In the Low-frequency Domain For Elastic Constant Det...mentioning

confidence: 99%

A Review on Acoustics of Wood as a Tool for Quality Assessment

Bucur

2023

Forests

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Acoustics is a field with significant application in wood science and technology for the classification and grading, through non-destructive tests, of a large variety of products from standing trees to building structural elements and musical instruments. In this review article the following aspects are treated: (1) The theoretical background related to acoustical characterization of wood as an orthotropic material. We refer to the wave propagation in anisotropic media, to the wood anatomic structure and propagation phenomena, to the velocity of ultrasonic waves and the elastic constants of an orthotropic solid. The acoustic methods for the determination of the elastic constants of wood range from the low frequency domain to the ultrasonic domain using direct contact techniques or ultrasonic spectroscopy. (2) The acoustic and ultrasonic methods for quality assessment of trees, logs, lumber and structural timber products. Scattering-based techniques and ultrasonic tomography are used for quality assessment of standing trees and green logs. The methods are based on scanning stress waves using dry-point-contact ultrasound or air-coupled ultrasound and are discussed for quality assessment of structural composite timber products and for delamination detection in wood-based composite boards. (3) The high-power ultrasound as a field with important potential for industrial applications such as wood drying and other applications. (4) The methods for the characterization of acoustical properties of the wood species used for musical instrument manufacturing, wood anisotropy, the quality of wood for musical instruments and the factors of influence related to the environmental conditions, the natural aging of wood and the effects of long-term loading by static or dynamic regimes on wood properties. Today, the acoustics of wood is a branch of wood science with huge applications in industry.

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“…A number of studies have also demonstrated the effectiveness of acoustic methods for NDE of standing trees (Senalik et al, 2014, Rudnicki et al, 2017, which could be useful for improving the efficiency and usable yield of harvests of whole timber for construction purposes.…”

Section: Acoustic Methodsmentioning

confidence: 99%