• Journal of Forest and Environmental Science
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• v.11 no.1
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• pp.50-60
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• 1995

This study was carried out to estimate drying schedules of Larix Leptolepis and Pinus koraiensis by oven-drying at $100^{\circ}C$ which aimed to elucidate the characteristics such as current moisture content, drying process. initial check, collapse, internal check and drying rate during drying following each board thickness (2, 3. 4, 5, 6cm). the results were summerized as follows; Current moisture content of each board showed a rapid drying curve with the decrease of board thickness. At 20% moisture content, the drying rate of Larix leptolepis was higher than that of Pinus koraiensis and the drying rate of boards was lower with the increase of board thickness. From the estimated drying schedules. the initial conditions of drying of Larix leptolepis had to be milder than those of Pinus koraiensis and the boards thickness of 5cm, 6cm had to be most mild conditions.

• Journal of Korean Society of Forest Science
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• v.96 no.1
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• pp.40-47
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• 2007

The objectives of this study were to derive site index and stem volume prediction equation based on stem analysis data for Larix leptolepis in Jinan region. The function for site index was developed by algebraic difference equation method. Polymorphic site index family curves with base age of 40 were presented based on the Schumacher height equation. The best stem volume prediction equation was suggested as $V=0.00260+0.00000399D^2H$. The simultaneous F-test using this equation showed that the estimated tree stem volumes were not significantly different (${\alpha}=0.05$ level) from the observed stem volumes for model evaluation. Therefore, site index and volume prediction equations prepared in this study could provide an indication of site quality and basic information for making of yield table, and could be used for rational forest management of Larix leptolepis stands grown in Jinan region.

• Journal of the Korean Wood Science and Technology
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• v.38 no.1
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• pp.49-55
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• 2010

morphologically different Larix Kaemferi Carr sawdust. The pellet characteristics included moisture contents satisfied the first grade (less than 10%) of quality standard of wood pellets announced by Korea Forest Research Institute. Densities were also adequate for the first grade (640kg/$m^3$) on the quality standard and there was no large difference in other characteristics of pellets, however, pellets manufactured with planer shavings had the highest density. Ash contents also passed the first grade (less than 0.7) of quality standard. But bark pellet exceeded the second grade (1.5%) in ash content. Lower absorption ratio of bark pellet showed the effect on hygroscpicity. The heating value of the manufactured wood pellets in this study exceeded the first grade of quality standard(more than 4,300 kcal/kg).

• Journal of Forest and Environmental Science
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• v.21 no.1
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• pp.24-33
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• 2005

Fallen needles (8.5kg) of Larix kaempferi were separately collected, extracted with 95% EtOH. EtOH extract was evaporated under reduced pressure, concentrated then successively fractionated with a series of hexane, methylene chloride, ethylacetate and water on a separatory funnel. Then, each fraction was freeze dried. A portion of ethylacetate and water soluble powder were packed on a column chromatography (Sephadex LH-20) eluting with aqueous MeOH and EtOH-hexane mixture. Spectrometric analyses such as NMR and FAB-MS including TLC were performed to characterize the structures of isolated compounds. 5 compounds were isolated from the fallen needles of Larix kaempferi. The antioxidative activities of each fraction and isolated compounds were done by DPPH radical scavenging test.

• Journal of agriculture & life science
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• v.52 no.6
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• pp.37-47
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• 2018

The objective of this study was to analyze the influences of forest management activity on the diameter distribution of Larix kaempferi Carriere stands in South Korea. We used 232 managed stands data, 47 unmanaged stands data of National Forest Inventory for this study. We employed the Weibull distribution function for estimating diameter based on percentiles and parameter recovery method. The results revealed that the average diameter breast height movements and growth of tree in the managed stands higher than the unmanaged stands according to the scenario: age, site index, and tree density change. The finding shows the percentage of the total amount of large class diameter was also high in the managed stands. The results of this study could be apply for the estimation of multi-products of timbers per diameter classes and stand structure development for Larix kaempferi Carriere stands in South Korea.

• Journal of the Korean Wood Science and Technology
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• v.51 no.5
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• pp.419-430
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• 2023

In this study, the floor impact sound insulation performance of Korean domestic Cross-Laminated Timber (CLT) slabs was evaluated according to their joint types, species and thicknesses in laboratory experiments. The sound insulation performance of the CLT has not been investigated before, thus, this study was conducted to quantify basic data on floor impact sound insulation performance of CLT slabs. 5-ply and 150 mm thick CLT panels made of 2 species, Larix kaempferi and Pinus densiflora, were used for the study. The CLT panels were assembled by 3 types of inter-panel joints to form floor slabs: spline, butt and half-lap. And the 150 mm thick Larix CLT slabs were stacked to the thicknesses of 300 mm and 450 mm. The heavy-weight floor impact sound insulation performance of the 150 mm CLT slabs were evaluated to be 70 dB for the Larix slabs and 71.6 dB for the Pinus slabs, and the light-weight floor impact sound insulation performance, 78.3 dB and 79.6 dB, respectively. No significant difference in the sound insulation performance was found between the slabs of the 2 species or among the 3 types of joints. The reduction of 1 dB in the heavy-weight floor impact sound and 1.6 dB in the light-weight floor impact sound per 30 mm increase in thickness were confirmed through the experiments. This study can be viewed as the basic research for the evaluation of floor impact sound insulation performance of CLT.

• Journal of Korean Society of Forest Science
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• v.17 no.1
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• pp.1-15
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• 1973

In an effort to improve the major tree species in Korea, the seed of Robinia pseudoacacia, Pinus rigida, Pinus densiflora, Pinus thunbergii and Larix leptolepis were treated with X-ray and thermal neutron at the Brookhaven National Laboratory, and germination rate of the seed and some characteristics of the seedlings from irradiated seed were investigated and the results were summarized as follows. 1. The germination rate of the irradiated seed of Robinia pseudoacacia, Pinus densiflora, Pinus thunbergii and Pinus rigida was decreased, when the irradiation time of thermal neutron increased from 3 hours to 9 hours. The seed of Larix leptolepis was completely died out in all range of irradiation time. 2. The seed of Pinus densiflora, Robinia pseudoacacia and Pinus rigida showed low germination rate, when the dosage of radiation increased in the range of 10,000r-30,000r X-ray. This dosage of radiation was almost lethal to the seed of Pinus thunbergii and Larix leptolepis. 3. The growth rate of radiated Robinia pseudoacacia has been decreased when the dosage of X-ray and thermal neutron increased. However, the trees treated with thermal neutron for 3 hours showed 14.9 percent-increase in seedling height and some thornless individuals appeared in this treatment. 4. Individuals with variegated leaf, rugose leaf and albino were appeared in X-ray and thermal neutron treatment. 5. Abnormal mitosis of somatic cell, cell with two nucleoli, cell with two nuclei and chromosome clump in mitosis of somatic cell were observed in Robinia pseudoacacia irradiated with thermal neutron. 6. Resistanty against pawdery mildew was decreased in Robinia pseudoacacia radiated with X-ray and thermal neutron. 7. Length of stomata did not show any difference however number of stomata per unit area decreased in Robinia pseudoacacia radiated with thermal neutron. The leaves of Robinia pseudoacacia radiated with thermal neutron were thicker than those of non-treated one, but width of palisade tissue was decreased. The most sensitive one among those species to the thermal neutron treatment was Larix leptolepis, followed by Pinus densiflora, Robinia pseudoacacia, Pinus thunbergii and Pinus rigida in the order. In X-ray treatment, the most sensitive one was Larix leptolepis, followed by Pinus densiflora, Pinus thunbergii, Pinus rigida and Robinia pseudoacacia in the order. Morphological, cytological variation of the radiated Robinia pseudoacacia seemed to indicate some possibility to be used for tree improvement.

• Journal of Korean Society of Forest Science
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• v.109 no.4
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• pp.413-420
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• 2020

We analyzed the growth characteristics of each cell line and acclimating substrate of Larix kaempferi plantlets regenerated from somatic embryos, with the goal of increasing the survival rate during the acclimation phase. Somatic embryos from three embryogenic cell lines (L14-66, L16-18, and L17-B4) were used, and the acclimating substrates were commercial soils for Larix species (Larix-Soil) and horticultural corps (Hort-Soil), Elle-pot, and Peat-plug. The average initial shoot and root length was shortest in L14-66 and longest in L17-B4. The average survival rate by cell line was highest (87.0%) in L17-B4 and lowest (64.3%) for L14-66. Survival rates by substrate were highest in Elle-pot (88.5%) and Peat-plug (88.9%). The initial shoot length of the L14-66 plantlets was highly correlated with survival rates in the Larix-Soil (r = 0.852), Hort-Soil (r = 0.692), and Elle-pot (r = 0.867) substrates, but not in Peat-plug with high total nitrogen content. The initial shoot length of the L17-B4 plantlets was not correlated with the survival rate in any of the substrates. The initial root length of the L14-66 plantlets was highly related to survival rates in the Larix-Soil (r = 0.986), Elle-pot (r = 0.846), and Peat-plug (r = 0.802) substrates, and the survival rate of the plantlets was higher as the initial root length was longer. The initial root length of the L17-B4 plantlets was related to survival rate only in the Larix-Soil (r = 0.896) and Elle-pot (r = 0.696) substrates. In conclusion, to increase the survival rate of plantlets, root length should be considered over shoot length, and it is recommended to use substrates with high nitrogen content, such as Peat-plug, or to add fertilizer, during the acclimating process. In addition, in order to increase the survival rate, lines with high initial growth should be developed.

• Journal of the Korea Furniture Society
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• v.20 no.4
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• pp.281-289
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• 2009

This research examined the technical feasibility of composite that had two layers of fiberglass reinforcement to enhance the load carrying capacity of lumber. Specimens were prepared from standard lumber made of thinning crop trees such as Larix kaempferi, Pinus koraiensis, and P. rigida. Results indicated that bending properties, hardness, and wood screw withdrawal load of low density lumber from the P. koraiensis increased as the number of layers of fiberglass reinforcement increased. Composite produced by VARTM method showed the MOE increased in all specimens, while the MOR differed on the location, whether the 2-layers of FRP is put on tensile zone or compressive zone. The MOR of high density lumber from Larix kaempferi and P. rigida decreased when they placed into tensile zone, but low density lumber from P. koraiensis increased in same location. The bending toughness only increased high density lumber of Larix kaempferi as the number of layers of fiberglass reinforcement increased. The technique developed by this study may increase an opportunity to use small diameter log with low density for commercial purposes.

• Journal of Forest and Environmental Science
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• v.30 no.2
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• pp.201-207
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• 2014

This study was conducted to estimate the best-fit nonlinear height-DBH growth models for Larix kaempferi in Gangwon and North Gyeongsang province in South Korea. Exponential, Modified Logistic, Chapman-Richards, and Weibull function were used for estimating height-DBH models. To evaluate the selected models, $R^2$, RMSE, MD, MAD, and residual plots were performed in each model. Also, the coefficients and patterns in models of the previous studies were compared with those in this study. The result showed that Weibull equation was found to be the best-fit model with $R^2$=0.9837, RMSE=2.6133, MD=0.0089, and MAD=2.0896. All model parameters in our study had similar values to those in the previous models except for asymptotic parameter a. Our research result showed that Gangwon and North Gyeongsang province were superior to other provinces with regard to height growth for Larix kaempferi.