• Journal of Forest and Environmental Science
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• v.23 no.2
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• pp.87-91
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• 2007

The needles of L. kaempferi was extracted with 95% ethanol and successively partitioned with n-hexane, $CH_2Cl_2$ and EtOAc. Repeated column chromatography on the EtOAc and $H_2O$ soluble fractions gave three flavan-3-ols, one flavone glycoside, six flavonol glycosides and one lignan derivative. Their structures were elucidated on the basis of chemical and spectroscopic evidences. The antioxidant activities of the isolated compounds were evaluated by DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging method. Flavan compounds indicated good antioxidative potentials compared with BHT (butylated hydroxytoluene) and ${\alpha}$-tocopherol as controls. In the anti-inflammatory test on most of the isolated compounds, NO (nitric oxide) assay against the RAW 264.7 (Mouse Macrophage) showed similar inhibitory potentials to NO production of the control. The cytotoxicity was determined by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay and most of the isolated compounds indicated no toxicity in various concentration.

• 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.

• Journal of Forest and Environmental Science
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• v.39 no.4
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• pp.195-202
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• 2023

In this study, we sought to compare and evaluate the accuracy and predictive performance of machine learning algorithms for estimating the growth of individual Larix kaempferi trees in Gangwon Province, Korea. We employed linear regression, random forest, XGBoost, and LightGBM algorithms to predict tree growth using monitoring data organized based on different thinning intensities. Furthermore, we compared and evaluated the goodness-of-fit of these models using metrics such as the coefficient of determination (R²), mean absolute error (MAE), and root mean square error (RMSE). The results revealed that XGBoost provided the highest goodness-of-fit, with an R² value of 0.62 across all thinning intensities, while also yielding the lowest values for MAE and RMSE, thereby indicating the best model fit. When predicting the growth volume of individual trees after 3 years using the XGBoost model, the agreement was exceptionally high, reaching approximately 97% for all stand sites in accordance with the different thinning intensities. Notably, in non-thinned plots, the predicted volumes were approximately 2.1 m³ lower than the actual volumes; however, the agreement remained highly accurate at approximately 99.5%. These findings will contribute to the development of growth prediction models for individual trees using machine learning algorithms.

• Journal of Forest and Environmental Science
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• v.40 no.1
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• pp.35-42
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• 2024

The Japanese larch (Larix kaempferi [Lamb.] Carriere) is a major timber species in Korea. However, studies on bucking rates and merchantable logs of this species are insufficient in South Korea. To bridge these gaps, in this study, the bucking rate of Japanese larch (Larix kaempferi [Lamb.] Carriere) was computed and the number of long logs and merchantable log volumes were analyzed. Sample trees were bucked according to the log grade for trading, and collected from a forest field in Gangwon Province. The bucking rate of all Japanese larch logs was >89%. The highly profitable 2-4 logs of 3.6 m length from trees with ≤30 cm diameter at breast height (DBH) and 5-6 logs with ≥34 cm DBH were produced. The bucking rate of long logs was >84%; thus, Japanese larch was found to be suitable for the supply of high-grade timber. Additionally, to follow reasonable wood supply plans, merchantable volume tables were offered based on 3.6 m-long number of logs and small-end diameter classes. Understanding the proportion of merchantable log volumes, bucking rates, and the number of long and short logs has large-scale applications in practical forestry.

• Journal of the Korea Furniture Society
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• v.13 no.2
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• pp.11-18
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• 2002

This study was carried out to investigate the strength and technical feasibility of glulam from small diameter Pinus densiflora and Larix kaempferi. Small diameter logs are currently not used in structural laminated beam construction, but it is suggested that its properties may be feasible for this purpose. The glulam combinations were designed with high grade laminae located at outer laminations (face) and low grade laminae located at center laminations. Important problems of finger jointed glulam as a structural beam are the small modulus of rupture (MOR). One solution for this problem Mi to use veneer and solid wood as the face laminae. The MOE values were predicted for each beam from laminae. The results showed that actual beam MOE values exceeded slightly the predicted values. Based on the evaluation and analysis of Pinus and Larix glulam, the maximum load of Larix kaempferi glulam indicated large values. The bending properties of A and E types glulam were superior to others. It is suggested that this small diameter log can be a candidate for structural glulam construction, providing the proper combinations of face laminae.

• Journal of the Korean Wood Science and Technology
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• v.37 no.1
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• pp.65-72
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• 2009

Variation of wood rays within a growth ring and along axial direction in Pinus koraiensis and Larix kaempferi, which are important Korean commercial softwoods, was examined to get some useful information for their effective utilization. Ray height in cell number and ray number per $0.25mm^2$ in tangential section were investigated by optical microscopy. The average heights of uniseriate rays in Pinus koraiensis and Larix kaempferi were 6.3 and 9.1 cells, respectively. The average numbers of uniseriate rays per $0.25mm^2$ in Pinus koraiensis and Larix kaempferi were 6.5 and 7.5, respectively. The average heights of fusiform rays were about 20 cells but were not significantly different in both species. From earlywood to latewood within a growth ring, the heights of uniseriate and fusiform rays decreased but their numbers remained almost constant. Along axial direction, the heights of uniseriate rays in both species increased with the increase of stem height, and the numbers of uniseriate rays per $0.25mm^2$ in Pinus koraiensis were nearly constant from 0.2 m to 5.2 m but increased up to 19.2 m beyond 5.2 m. However, a constant pattern in the numbers of uniseriate rays was not observed in Larix kaempferi. The heights of fusiform rays in both species were the highest in middle part of stems but were the lowest in base and top of trees. In conclusion, the ray variation pattern was comparatively clear within a growth ring but not clear along axial direction.

• Journal of Ecology and Environment
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• v.29 no.3
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• pp.205-212
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• 2006

Effects of nitrogen and phosphorus fertilization on nutrient dynamics and litterfall production were determined in adjacent 41-year-old plantations of Pinus rigida Miller and Larix kaempferi Gordon on a similar soil in Yangpyeong, Gyeongggi Province. Litterfall production were significantly different among sampling dates and between the tree species, whereas it was not significantly different among the treatments. Total annual litterfall production was 6,377 kg/ha for P. rigida and 4,778 kg/ha for L. kaempferi, respectively. Litterfall nutrient concentrations of L. kaempferi were higher than those of P. rigida. For both tree species, litterfall nutrient concentrations were highest in summer when the least litterfall production occurred, and lowest in late-autumn when the greatest litterfall production occurred, except for Ca in the L. kaempferi stand. The amount of total organic matter in the forest floor of P. rigida and L. kaempferi plantations were 24,296 kg/ha and 10,763 kg/ha, respectively. Forest floor N and P contents were 126, 10 kg/ha for P. rigida and 102, 8 kg/ha for L. kaempferi, respectively.

• Journal of Korean Society of Forest Science
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• v.106 no.1
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• pp.10-18
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• 2017

This study was carried out to suitable plantation site from comparison and analysis of regional early growth characteristics of planted Larix kaempferi trees in harvested L. kaempferi plantations. Two-year-old bare-root seedlings of L. kaempferi were planted with the density of $3000\;seedlings\;ha^{-1}$ at four sites (Yeongju, Gimcheon, Chuncheon, and Inje). All sites were established with three plots ($400m^2$ per plot) in 2010. We analyzed soil physical and chemical properties in October 2010 and 2013. We measured root collar diameter (RCD) and height of trees in October from 2010 to 2014, and then calculated H/D ratio and stem volume. Soil pH was significantly increased and available P was significantly decreased 3 years after planting. Annual mean RCD, height, and stem volume of 5-to 7-year-old in the Chuncheon site were significantly higher than those in the other sites, however them in the Yeongju site were the lowest. It is related to the fact that total nitrogen, available phosphorus, and organic matter concentrations in the Yeongju site were relatively lower than those in the other sites. As a results of this study, we could confirm the correlation between soil properties of L. kaempferi plantations and growth of L. kaempferi trees. We could suggest values of soil properties for reforestation of L. kaempferi.

• Journal of Korean Society of Forest Science
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• v.108 no.4
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• pp.522-530
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• 2019

Two edible plants, Allium victorialis var. platyphyllum and Ligularia stenocephala, and one medicinal plant, Panax ginseng, were cultivated in the understory of an artificial Larix kaempferi plantation for ten years. Growth characteristics (number of leaves and flower stalks per plant, and leaf length and width), survival rate, and yield (fresh weight of plants) per unit area (1 ㎡) were investigated one year after planting, and six and ten years following cultivation. P. ginseng and L. stenocephala survived at a high percentage for two years after planting. Results showed that P. ginseng had longer and thicker roots when aged; however, a large number of plants died and the yield was low. In contrast, almost half of A. victorialis var. platyphyllum died within two years of planting. The surviving plants grew well for ten years and the yield was increased. The leaf length and width of L. stenocephala increased; however, the survival rate and the number of leaves per plant decreased as the period of cultivation was extended. In contrast, A. victorialis var. platyphyllum survived at a lower rate (50%) than the two other crops (98% for L. stenocephala and 83% for P. ginseng) during the early cultivation period, with little change in the survival rate over an extended time; however, the yields increased. This species showed an increase in the number of flower stalks and leaves, and as a result, the larger leaves increased the yield. We evaluated the understory cultivation of three crops in a L. kaempferi plantation under natural conditions, with no irrigation or fertilization, and Allium victorialis var. platyphyllum showed the greatest growth potential among the three tested crops.