Predicting the bending properties of Larix sibirica lumber using nondestructive-testing methods

International Wood Products Journal

Nezu

et al. 2020

Self Cite

Wood properties were investigated for nine naturally regenerated trees of Betula platyphylla Sukaczev var. japonica (Miq.) H. Hara in Nikko, Japan to effectively utilise the wood resources. The following properties were determined: stress-wave velocity of stems in radial direction, cell length, basic density, shrinkage, dynamic Young's modulus, modulus of elasticity, modulus of rupture, absorbed energy in impact bending, and compressive strength parallel to grain. All examined wood properties increased from pith to bark. The boundary between core and outer wood determined by a 1.0% annual increment of cell lengths was well matched with that determined by radial variations of wood properties. Significant differences were found between the core and outer wood in several wood properties. Based on the results, it is concluded that when the wood of B. platyphylla is utilised as an industrial raw material, the presence of core and outer wood should be considered.

Section: Methodsmentioning

confidence: 99%

Within-tree and radial variations of wood properties in naturally regenerated trees of Betula platyphylla grown in Nikko, Japan

Erdene-Ochir

International Wood Products Journal

Nezu

et al. 2020

Self Cite

“…Table 1 shows geographic and climatic information for the five provenances and the growth characteristics of the harvested trees [33][34][35][36] . A total of 25 trees with straight stems that did not have any severe damage were collected from five natural L. sibirica forests located in five different provenances (five trees in each forest) in Mongolia [33][34][35][36] . These five provenances are famous Larix forestry sites in Mongolia.…”

Section: Methodsmentioning

confidence: 99%

“…We have previously reported geographical variations in the growth characteristics, log properties, and lumber quality of L. sibirica in Mongolia 33 – 36 . We found significant differences in the tree height, dynamic Young’s modulus of logs, annual ring width, and bending properties of lumber among five provenances in Mongolia, although the stem diameters 1.3 m above ground were almost the same.…”

Section: Introductionmentioning

confidence: 99%

Physical and mechanical properties of wood and their geographic variations in Larix sibirica trees naturally grown in Mongolia

Tumenjargal

Aiso³

et al. 2020

Sci Rep

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We examined the physical and mechanical properties of wood in Siberian larch (Larix sibirica) trees that grow naturally in five Mongolian provenances (Khentii, Arkhangai, Zavkhan, Khuvsgul, and Selenge) and the geographic variations between them. Five trees with stem diameters of 20 to 30 cm at 1.3 m above ground were collected from each provenance. The mean values of the modulus of elasticity (MOE), modulus of rupture (MOR), compressive strength parallel to grain (CS), and shearing strength (SS) ranged from 7.03 to 9.51 GPa, 79.8 to 103.9 MPa, 46.3 to 51.1 MPa, and 10.4 to 13.0 MPa, respectively. Significant differences were found in radial and tangential shrinkage, MOE, MOR, and SS in wood among the five provenances. In addition, juvenile wood had inferior physical and mechanical properties in comparison to mature wood within and among provenances. Furthermore, there were significant differences in all examined properties, except for CS, in mature wood among the five provenances. Higher correlation coefficients were also obtained in mature wood among all mechanical properties, except for SS. Larix species are one of the most productive forestry species in North America 1-4 , Europe 5-12 , Japan 13-24 , and China 25,26. To date, several studies have focused on geographic variations in the physical and mechanical properties of wood in Larix species to determine effective wood utilization and conduct appropriate tree breeding programs 1,3-5,15,18,19,23,24. For example, geographic variations have been found in the physical and mechanical properties of wood in Larix kaempferi 1,4. A similar tendency was also found for another Larix species, Larix sibirica 5. In addition to geographic and/or genetic variations in the physical and mechanical properties of wood, radial variations should also be considered for effective wood utilization 11,12,23-25,27. In general, softwood can be classified as juvenile or mature wood. Juvenile wood is characterized by a greater microfibril angle, a lower basic density, and inferior mechanical properties compared to mature wood 12-15,17,23,24,26,28,29. In a study of 31-year-old L. kaempferi trees, wood density and wood mechanical properties, such as modulus of elasticity (MOE), modulus of rupture (MOR), compressive strength parallel to grain (CS), and shearing strength (SS), showed lower values in corewood (from the pith to the 15th annual ring) than in outer wood (from the 15th annual ring to the bark) 24. Therefore, based on the nature of Larix species, (1) trees of these species with superior physical and mechanical properties of wood can be selected, and (2) the properties of juvenile wood should be considered for determining effective wood utilization. In Mongolia, the total forest area is 18.3 million ha, covering 11.9% of the country 30. Of this total area, Larix sibirica covers more than 70% of the forest. Since wood produced from Larix species is mainly utilized for structural applications, sawmilling is one of the main forest activities in Mongolia. Indeed, L. sibirica is the m...

“…Thus, radial and longitudinal variations of wood properties should be clarified to effectively utilize wood resources. We have investigated the detailed wood properties in several species naturally grown in Mongolia (Ishiguri et al 2018;Tumenjargal et al 2018;Tumenjargal et al 2019;Tumenjargal et al 2020a;Tumenjargal et al 2020bTumenjargal et al , 2020cAyush et al 2019;Erdene-Ochir et al 2020;Sarkhad et al 2020Sarkhad et al , 2022. However, further research is needed to investigate the detailed wood property in the Mongolian softwood species to achieve the effective utilization of Mongolian wood resources.…”

Section: Introductionmentioning

confidence: 99%

Log characteristics and basic density of four common Mongolian softwoods

Sarkhad

International Wood Products Journal

Nezu

et al. 2022

Self Cite

Log characteristics and basic density were evaluated in four common Mongolian softwoods, Pinus sylvestris L., Pinus sibirica Du Tour, Picea obovata Ledeb., and Larix sibirica Ledeb. by developing the linear or nonlinear mixed-effects models for longitudinal and radial variations of measured characteristics. Total of 19 trees from four species were used in this study. Log taper and juvenile wood percentage increased from base to treetop in all species, except for log taper in Pinus sylvestris. Dynamic young's modulus of logs decreased from base to treetop, and the mean values were 7.81, 5.74, 7.12, and 8.78 GPa for Pinus sylvestris, Pinus sibirica, Picea obovata, and Larix sibirica, respectively. Basic density increased (Pinus sylvestris and Larix sibirica) or decreased (Pinus sibirica and Picea obovata) and then became stable values. The estimated whole tree values of basic density in juvenile wood significantly differed from those in mature wood for all species.