Can needle nitrogen content explain the interspecific difference in ozone sensitivities of photosynthesis between Japanese larch (Larix kaempferi) and Sakhalin fir (Abies sachalinensis)?

Research Highlights: The complete chloroplast genome for eight individuals of Japanese larch, including from the isolated population at the northern limit of the range (Manokami larch), revealed that Japanese larch forms a monophyletic group, within which Manokami larch can be phylogenetically placed in Japanese larch. We detected intraspecific variation for possible candidate cpDNA markers in Japanese larch. Background and Objectives: The natural distribution of Japanese larch is limited to the mountainous range in the central part of Honshu Island, Japan, with an isolated northern limit population (Manokami larch). In this study, we determined the phylogenetic position of Manokami larch within Japanese larch, characterized the chloroplast genome of Japanese larch, detected intraspecific variation, and determined candidate cpDNA markers. Materials and Methods: The complete genome sequence was determined for eight individuals, including Manokami larch, in this study. The genetic position of the northern limit population was evaluated using phylogenetic analysis. The chloroplast genome of Japanese larch was characterized by comparison with eight individuals. Furthermore, intraspecific variations were extracted to find candidate cpDNA markers. Results: The phylogenetic tree showed that Japanese larch forms a monophyletic group, within which Manokami larch can be phylogenetically placed, based on the complete chloroplast genome, with a bootstrap value of 100%. The value of nucleotide diversity (π) was calculated at 0.00004, based on SNP sites for Japanese larch, suggesting that sequences had low variation. However, we found three hyper-polymorphic regions within the cpDNA. Finally, we detected 31 intraspecific variations, including 19 single nucleotide polymorphisms, 8 simple sequence repeats, and 4 insertions or deletions. Conclusions: Using a distant genotype in a northern limit population (Manokami larch), we detected sufficient intraspecific variation for the possible candidates of cpDNA markers in Japanese larch.

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Short-term effects of tree thinning on microhabitat variables and rodents in Japanese larch Larix kaempferi forest

Forest Science and Technology ◽

10.1080/21580103.2021.1880976 ◽

2021 ◽

pp. 1-7

Author(s):

Seung-Hun Son ◽

Jae-Kang Lee ◽

Hyun-Su Hwang ◽

Tae-Kyung Eom ◽

Shin-Jae Rhim

Keyword(s):

Japanese Larch ◽

Larix Kaempferi ◽

Short Term ◽

Tree Thinning ◽

Short Term Effects

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Withdrawal Properties of Self-Tapping Screws in Japanese larch (Larix kaempferi (Lamb.) Carr.) Cross Laminated Timber

Forests ◽

10.3390/f12050524 ◽

2021 ◽

Vol 12 (5) ◽

pp. 524

Author(s):

Junhua Xu ◽

Shuangbao Zhang ◽

Guofang Wu ◽

Yingchun Gong ◽

Haiqing Ren

Keyword(s):

Regression Model ◽

Engineering Design ◽

Wood Species ◽

Japanese Larch ◽

Effective Length ◽

Larix Kaempferi ◽

Cross Laminated Timber ◽

The World ◽

Different Types ◽

Length Increment

With the increasing popularity of cross-laminated timber (CLT) constructions around the world, there have been attempts to produce CLT using local wood species in different countries, such as Japanese larch (Larix kaempferi (Lamb.) Carr.) in China. Thus, the need to investigate the connection performance also increases to support the design and construction of CLT buildings using local wood species. In this study, the withdrawal properties of three different types of self-tapping screws (STS), with a diameter of 6 mm, 8 mm, and 11 mm, were tested with Japanese larch CLT. The results revealed that the withdrawal strength of STS increased with increasing density and effective length, but decreased with an increasing diameter. With a density increment of 0.05 g/cm3, the withdrawal strength increased by an average of 9.4%. With an effective length increment of 24 mm, the withdrawal strength increased by an average of 1.4%. An empirical regression model was adopted to predict the withdrawal strength of Japanese larch CLT based on the results, which can be used for potential engineering design of CLT connections using STS.

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Upgrading the fuel properties of hydrochar by co-hydrothermal carbonisation of dairy manure and Japanese larch (Larix kaempferi): product characterisation, thermal behaviour, kinetics and thermodynamic properties

Biomass Conversion and Biorefinery ◽

10.1007/s13399-021-02045-0 ◽

2021 ◽

Author(s):

Mohammed Aliyu ◽

Kazunori Iwabuchi ◽

Takanori Itoh

Keyword(s):

Thermal Behaviour ◽

Total Pore Volume ◽

Dairy Manure ◽

Fuel Properties ◽

Japanese Larch ◽

Larix Kaempferi ◽

Mass Ratio ◽

Fixed Carbon ◽

Solid Biofuel ◽

Hydrothermal Carbonisation

AbstractThis study investigated co-hydrothermal carbonisation (co-HTC) of dairy manure (DM) and wood shavings from Larix kaempferi, commonly known as the Japanese larch (JL) to enhance the fuel properties of the resulting hydrochar. The JL was mixed with the DM at 25, 50 and 75 wt.% ratios. Co-HTC was conducted at 260 °C for 20 min. The resulting hydrochars were characterised based on the physicochemical properties and the thermal behaviour. Results showed that the hydrochar solid biofuel properties improved as the ratio of JL was increased. The produced hydrochars were in the region of lignite and closed to the region of the coal with increased fixed carbon, carbon contents and lowered H/C and O/C ratios. Hydrochar with ash content of 7.2 ± 0.5% was obtained at 75 wt.% JL. In addition, the HHV of hydrochar increased remarkably to 26.4 ± 0.02 MJ/kg as the mass ratio of the JL was increased. The surface morphology of the hydrochars were altered and became distinct while the specific surface area (SSA) and the total pore volume (TPV) of the hydrochars increased at increasing the mass ratio of the JL. The surface functional groups were also altered by the co-HTC process. A decline in the combustion performance was observed after the HTC process but improved at 75 wt.% JL after the co-HTC process. The kinetic analysis also revealed that the activation energy decreased after the HTC process but increased to a higher value at 50 wt.% JL after the co-HTC process. Therefore, hydrochar production by co-HTC of DM and JL has proved to be an effective and promising solid biofuel source. Graphical abstract

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Long-term bending properties of cross-laminated timber made from Japanese larch under constant environment

Journal of Wood Science ◽

10.1186/s10086-021-01997-1 ◽

2021 ◽

Vol 67 (1) ◽

Author(s):

Ryuya Takanashi ◽

Yoshinori Ohashi ◽

Wataru Ishihara ◽

Kazushige Matsumoto

Keyword(s):

Load Capacity ◽

Creep Rupture ◽

Japanese Larch ◽

Larix Kaempferi ◽

Loading Capacity ◽

Loading Test ◽

Cross Laminated Timber ◽

Duration Of Load ◽

Rupture Behavior

AbstractCross-laminated timber (CLT) has been used extensively in timber construction. CLT panels are typically used in roofs and floors that carry a continuous load, and it is important to examine the long-term loading capacity of CLT. However, studies that focus on the long-term loading capacity of CLT are limited. To this end, we conducted long-term out-of-plane bending tests on seven-layer CLT made from Japanese larch (Larix kaempferi) under constant environmental conditions, investigated creep performance and duration of load, and experimentally analyzed creep rupture behavior. The mean estimated relative creep after 50 years was 1.49. The sample showed a satisfactory resistance to creep as a building material. The duration of load of most of the specimens in this study was shorter than the conventional value of small clear wood specimens. Specimens had a lower duration of load capacity than solid lumber. According to the results of survival analysis, a loading level of 70% or more caused the initial failure of specimens. Creep rupture of most of the specimens occurred at less deflection than displacement at failure in the short-term loading test. Additional studies focusing on the effects of finger joints, transverse layers, and width of a specimen on creep rupture behavior are suggested.

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