Preliminary evaluation for quality of dimension lumber in four common softwoods in Mongolia

Abstract

The quality of dimension lumber (2 by 4 lumber) was preliminarily investigated in four common Mongolian softwoods: Pinus sylvestris L., Pinus sibirica Du Tour, Picea obovata Ledeb., and Larix sibirica Ledeb. to produce high quality dimension lumber for structural use. In total 61, 39, 67, and 37 pieces of lumber were prepared for Pinus sylvestris, Pinus sibirica, Picea obovata, and L. sibirica, respectively. The lumber was visually graded and then tested in static bending to obtain the 5% lower tolerance limits at 75% confidence level (f0.05) of the modulus of elasticity (MOE) and the modulus of rupture (MOR). In addition, the effects of sawing patterns on bending properties were also analyzed. The f0.05 of the MOE and MOR were 4.75 GPa and 15.6 MPa, 3.39 GPa and 11.0 MPa, 3.78 GPa and 11.7 MPa, and 6.07 GPa and 22.3 MPa for Pinus sylvestris, Pinus sibirica, Picea obovata, and L. sibirica, respectively. These results suggested that with a few exceptions, characteristic values of MOR in the four common Mongolian softwoods resembled those in similar commercial species already used. In visual grading, over 80% of total lumber was assigned to select structural and No. 1 grades in Pinus sylvestris and Pinus sibirica, whereas approximately 40% of total lumber in L. sibirica was No. 3 and out of grades. Sawing patterns affected bending properties in Pinus sylvestris and L. sibirica, but did not affect Pinus sibirica and Picea obovata. Dynamic Young's modulus was significantly correlated with bending properties of dimension lumber for the four species. Based on the results, it was concluded that dimension lumber for structural use can be produced from the four common Mongolian softwoods.

Log characteristics and basic density of four common Mongolian softwoods

“…(Abbreviations in Model II) y ijk , measured value for the ith annual ring number from pith at the jth height position above the ground of the kth individual tree; ARN ijk , ith annual ring number from pith at the jth height position above the ground of the kth individual tree; β 0 , β 1 , and β 2 , the fixed effect parameters; e ijk , residual; u 0k( j) , u 1k( j) , or u 2k( j) , random effect parameters for β 0 , β 1 , or β 2 , respectively, at the jth height position above the ground nested within the kth individual tree. species mean level (Sarkhad et al 2020(Sarkhad et al , 2022. Even in the boundary cambial age was almost the same among four species, the distance from pith to boundary cambial age in transverse section was different among species: the ratios of distance from the pith to boundary cambial age to radius were 0.45, 0.50, 0.61, and 0.67 for Pinus sylvestris, Pinus sibirica, Picea obovata, and Larix sibirica, respectively (Figure 2).…”

“…were only collected from a limited area, Mandal, Selenge, Mongolia, although Mongolia has many natural forests in the country. The sample trees were the same as the previous study (Sarkhad et al 2020(Sarkhad et al , 2022. Five trees in each species were obtained.…”

“…The wedge-shape samples were again cut into Table 1. Stem diameter, tree height, annual rings, and boundary annual ring number between juvenile and mature wood of the sample trees (Sarkhad et al 2020(Sarkhad et al , 2022. specimens at 10-year intervals from the pith.…”

“…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.…”

Uplift capacity evaluation of light-framed wood structure’s roof-to-wall connections

“…Pinus sylvestris L. is widely distributed in Russia, Turkey, Mongolia, and the Greater Khingan Mountains Forest region of China. It has strong cold-resistance capability and does not require rich soil moisture conditions; thereby, it is capable for utilization as an afforestation tree species in mountainous and sand dune areas (Ekman et al 2002;Korkut et al 2008;Arriaga et al 2012;Cai et al 2016;Buyuksari et al 2017;Burawska-Kupniewska et al 2019;Sarkhad et al 2020;Sobierajska et al 2020). Pinus sylvestris L. has various apparent material performance, such as straight texture, clear pattern, moderate uniform structure, lightweight performance, low density, distinct rosin smell, high water resistance, high moisture resistance, good antifungal corrosion, and high durability, so it is mainly used in structural materials, and is also widely used in other wood production fields (Megnis et al 2002;Yildiz et al 2004;Rautiainen and Alen 2007;Temiz et al 2008;Simsek et al 2010;Bekhta et al 2014;Witomski et al 2014;Shen et al 2020).…”