Biomorphology of Spruce Trees as a Diagnostic Attribute for Non-Destructive Selection of Resonant Wood in a Forest

Abstract

Background and Purpose: Nowadays selection of resonant raw material in forests is not practically carried out; there are no standards and samples for a tree with such timber, and, consequently, rational target use of this unique natural material is not achieved. Thereof a lot of valuable wood remains in forests or is harvested for utilizing as general-purpose forest products or firewood. The research is focused on the studies of interrelation of resonant properties of wood and its biomorphological attributes such as crown diameter and height, trunk habitus, branchless zone extension, etc. materials and methods: Test material for the research of dendroacoustic parameters were cross-section radial cores 4.0 mm in diameter selected with an increment borer at breath height from 16 model trees after cutting them down. Simultaneously, diameters of trunks at relative heights (H) of 0.2Н, 0.5Н and 0.7Н, as well as branchless zone extension and tree crown parameters (its extension, first alive knot fastening height, etc.) were defined. Then, the interrelation was revealed between the biometric data of a tree trunk and average sound velocity measured across the trunk with UK-14П ultrasonic device at different relative heights. Results: The results submitted in this paper present practical value and assess the accuracy of standing spruce wood resonant properties' forecasting based on its 'wood study portrait' parameters. conclusions: Acoustic properties of wood depend on biomorphology of a tree as well. The parameters of stem tapering, trunk volume and especially branchless zone extension and crown elevation have, to any extent, the greatest practical value for standing resonant raw material express diagnostics.

Bark Features for Identifying Resonance Spruce Standing Timber

“…The relevance of the morphological bark and crown features in relation to the acoustic properties of the wood [8] lies in the contribution to the elastic-mechanical wood features of: crown metrics [72], stem knottiness [73], the repeated sway of the trees, and the factors that generate compression wood [51,74] and fibre twisting [12].…”

“…Recognizing standing trees that have resonance wood has always been a challenge for luthiers. Long-time observations revealed the distinct physiognomy of resonance trees [5][6][7], but the topic remained somewhat unsolved until some of the physiognomic features were acoustically verified [8]. The literature provided a few morphological descriptors of the stem and crown of resonance trees [9,10] and of raw resonance wood [11][12][13][14][15].…”

“…Given the indicative value of some traits of trees in relation to the material's acoustic quality, we shall hereafter call them phenotypical markers or morphological descriptors of resonance spruce. Some luthiers empirically associate resonance spruce with the phenotype of smooth or thin fissured barked trees with small, soft, and rounded scales, grouped vertically [8,9,18], which is different from regular spruce trees that have thicker and deeply furrowed bark at the harvesting age of the resonance wood [4]. Furthermore, spruce with indented rings is sought after by violin makers [19]-specifically indentations imprinting the underbark side [20].…”

“…Vibrational methods have already become common in identifying damages in standing trees [44][45][46][47] and assessing tree stiffness [48,49]. Using them in examining the tree goodness for the manufacture of musical instruments is still in the early stages [8]. New advanced methods, such as X-ray light microtomography coupled with scanning electron microscopy, are involved in describing the acoustical behavior of the wood [50].…”