• Journal of Forest and Environmental Science
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• 제23권2호
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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.

• 한국가구학회지
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• 제20권4호
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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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• 제30권2호
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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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• 제39권4호
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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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• 제40권1호
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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.

• 한국가구학회지
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• 제13권2호
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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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• 제37권1호
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• pp.65-72
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• 2009

잣나무와 낙엽송 조림목 수간 내에서 단열방사조직과 방추형방사조직의 연륜 내 및 축방향의 변이성을 조사하였다. 잣나무와 낙엽송의 단열방사조직의 높이는 각기 평균 6.3 및 9.1 세포고로서 낙엽송이 더 높았다. $0.25mm^2$ 면적당 단열방사조직의 개수는 각각 평균 6.5개 및 7.5개로써 낙엽송이 더 많았으며 방추형방사조직의 높이는 양 수종 모두 평균 20세포고 정도로서 거의 차이가 없었다. 연륜 내에서 조재부에서 만재부로 이행해 감에 따라 단열방사조직과 방추형방사조직의 높이는 감소하였으나 개수에는 거의 변화가 없었다. 축방향으로 단열방사조직의 세포고는 지상고가 증가함에 따라 점차 증가하였다. 단열방사조직의 개수는 잣나무에서 지상고 5.2m까지 거의 일정하였고 그 이상의 지상고부터 증가하였으나 낙엽송에서는 일관된 경향을 찾아보기 어려웠다. 방추형방사조직의 높이는 지상고가 낮은 수간의 기부에서 가장 낮았으며 수간의 중앙부로 올라감에 따라 높아 지다가 수관부에서 다시 낮아지는 경향이 있었다. 본 연구 결과, 연륜 내에서의 방사조직의 변이성은 비교적 뚜렷하였으나 축방향에서의 변이성은 일관된 경향이 없어 그 경향을 명확히 밝히는 것은 어려울 것으로 생각되었다.

• Journal of Ecology and Environment
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• 제29권3호
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• pp.205-212
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• 2006

본 연구는 경기도 양평지역 내 서로 인접하여 있고 동일한 입지 환경 위에 생육하고 있는 41년생 리기다소나무와 낙엽송 조림지를 대상으로 질소와 인 시비처리가 리기다소나무와 낙 엽송의 낙엽 생산량 및 양분 동태에 미치는 영향을 구명하기 위하여 수행되었다. 낙엽 생산량은 시료채취 시기와 수종간에 통계적으로 유의성이 인정된 반면, 시비 처리간에는 유의적인 차이가 없었던 것으로 나타났다. 연간 낙엽 생산량은 리기다소나무가 6,377 kg/ha 그리고 낙엽송이 4,778 kg/ha이었다. 낙엽 내 양분농도는 낙엽송이 리기다소나무에 비해 높았으며, 두 수종 모두 처리구간에 유의적인 차이가 있는 것으로 나타났다. 또한 낙엽 내 양분 농도는 낙엽송에서의 Ca 함량을 제외하고 두 수종 모두 연중 낙엽 생산량이 가장 많았던 늦가을에서 가장 낮았으며, 연중 낙엽 생산량이 가장 적었던 여름에 가장 높았던 것으로 나타났다. 또한 리기다소나무와 낙엽송 임분 임상의 총 유기물 함량은 24,296 kg/ha, 그리고 10,763 kg/ha였으며, 임상 내질소와 인의 함량은 리기다소나무가 126, 10 kg/ha, 그리고 102, 8 kg/ha로 각각 나타났다.

• 한국산림과학회지
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• 제106권1호
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• pp.10-18
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• 2017

본 연구는 낙엽송림 벌채 후 동일 수종인 낙엽송을 재조림하여 지역별 조림목의 생장을 비교 및 분석함으로써 낙엽송 조림목의 초기 생장 특성을 구명하고자 수행되었다. 조사지는 영주, 김천, 춘천, 인제이고, 낙엽송 노지묘(1-1)를 3000 본 $ha^{-1}$ 밀도로 식재하였다. 2010년과 2013년에 조림지 토양 특성 분석과 2010년부터 2014년까지 낙엽송 조림목의 근원경과 수고를 측정하여 H/D율과 수간 재적을 계산하였다. 낙엽송 식재 후 3년의 시간이 경과한 다음 pH는 유의하게 증가하였고, 유효인산 농도는 유의하게 감소하였다. 낙엽송 조림목이 5~7년생일 때 근원경, 수고 및 수간 재적 모두 매년 춘천 조사지에서 유의하게 가장 높았으며, 영주 조사지에서 가장 낮았다. 이는 영주 조사지 내 토양 전질소, 유효인산, 유기물 농도가 다른 조사지보다 상대적으로 낮았기 때문으로 판단된다. 본 연구 결과로 낙엽송 조림지 내 토양 특성과 조림목의 생장과의 상관을 확인할 수 있었으며, 낙엽송 재조림을 위한 토양 양분 수준을 제시할 수 있을 것이다.

• 한국산림과학회지
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• 제108권4호
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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.