• Journal of the Korean Wood Science and Technology
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• v.45 no.5
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• pp.525-534
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• 2017

The study aims to observe the cellular anatomical properties of Dahurian larch and Japanese larch for the species identification. In addition, other factors - the ring width, tracheid length, density, and strength - were compared and analyzed to clarify their physical and mechanical properties. To the end, three Dahurian larch trees and three Japanese larch trees by each diameter class were collected as specimens from Jeongseon-eup, Jeongseon-gun, Gangwon-do, to conduct a stem analysis. It was found that the average stand age, average diameter at breast height, and average tree height of three Dahurian larch trees and Japanese larch trees were 74 years and 51 years, 442 mm and 352 mm, and 26.1 m and 20.8 m, respectively. The cellular anatomical difference between Dahurian larch and Japanese larch can be usually found by spiral thickening, considering that it doesn't occur in Dahurian larch at all, while rarely does in the ray tracheids of Japanese larch. However, in this study, spiral thickening was not observed in the radial section of Japanese larch. The average annual growth diameters measured at 1.2 m-height of Dahurian larch and Japanese larch were 5.167 mm and 5.954 mm, respectively. Meanwhile, arboreal growth of Japanese larch was observed to be higher than that of Dahurian larch. In the physical properties test, it was measured that the latewood proportion and oven-dry density of Dahurian larch with low annual diameter growth were higher than those of Japanese larch, while the mechanical properties of Dahurian larch wood were measured 2-7% higher than those of Japanese larch wood. The data obtained from this study are expected to be used as the basic reference for species identification between Dahurian larch and Japanese larch by DNA analysis.

• Journal of Korean Society of Forest Science
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• v.105 no.1
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• pp.122-131
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• 2016

This study was conducted to analyze the effect of climatic variables on tree-ring growth of Larix leptolepis distributed in Korea by dendroclimatological method. For this, annual tree-ring growth data of Larix leptolepis collected by the $5^{th}$ National Forest Inventory were first organized to analyze yearly growth patterns of the species. To explain the relationship between tree-ring growth of Larix leptolepis and climatic variables, monthly temperature and precipitation data from 1950 to 2010 were compared with tree-ring growth data for each county. When tree-ring growth data were analyzed through cluster analysis based on similarity of climatic conditions, six clusters were identified. In addition, index chronology of Larix leptolepis for each cluster was produced through cross-dating and standardization procedures. The adequacy of index chronologies was tested using basic statistics such as mean sensitivity, auto correlation, signal to noise ratio, and expressed population signal of annual tree-ring growth. Response function analysis was finally conducted to reveal the relationship between tree-ring growth and climatic variables for each cluster. The results of this study are expected to provide valuable information necessary for estimating local growth characteristics of Larix leptolepis and for predicting changes in tree growth patterns caused by climate change.

• Journal of the Korean Wood Science and Technology
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• v.2 no.2
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• pp.25-31
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• 1974

1. Various gluing qualities applying Resorcinol Plyophen #6000 were studied on aiming the strength relationships of laminated woods resulted by single species [poplar (Populus deltoides), larch(Larix leptolepis)], mixed species of (poplar and larch), preservatives, treated poplar the scarf joint with mixed species of poplar and larch and the scarf joint treated with preservatives. 1. 1 On the block shear and on the DVL tension test, the mean wood failure ratio showed an excellent value i.e., above 65% and the tangential strength for larch was higher than that of radial, but it was reversed for poplar as shown in Tables 1 and 2. 1. 2 The lamina treated with Na-PCP reduced slightly the strength but the limited strength allowed for manufacturing laminated wood was not influenced by treating Na-PCP as shown in Tables 3 and 4. 1. 3 The safe scarf ratio in the plane scarf joint was above 1/12 for larch and 1/6 for poplar regard less of the chemical treatment or untreatment as shown in Tables. 5, 6, 7 and 8. 2. In the normal and boiled state, the gluing quality of the laminated wood composed of single[poplar (Populus deltoides), larch (Larix leptolepis)] and double species (poplar and larch) glued with Resorcinol Plyophen #6000 were measured as follow, and also represented the delamination of the same laminated wood. 2.1 The normal block shear strength of the straight and curved laminated wood (in life size) were more than three times of the standards adhesion strength. And, the value of the boiled stock was decreased to one half of the standard shear adhesion strength, but it was more than twice the standard strength for the boiled stock. Thus, it was recognized that the water resistance of the Resorcinol Plyophen #6000 was very high as shown in Tables 9 and 10. 2. 2 The delamination ratio of the straight and curved laminated woods in respect of their composition were decraesed, in turn, in the following order i. e., larch, mixed stock (larch+poplar) and poplar. The maximum value represented by the larch was 3.5% but it was below the limited value as shown in Table 11. 3. The various strengthes i.e., compressive, bending and adhesion obtainted by the straight laminaced wood which were constructed by five plies of single and double species of lamina i. e., larch (Larix leptolepis) and poplar (Populus euramericana), glued with urea resin were shown as follows: 3. 1 If desired a higher strength of architectural laminated wood composed of poplar (P) and larch (L), the combination of the laminas should be arranged as follows, L+P+L+P+L as shown in Table 12. 3.2 The strength of laminated wood composed of laminas which included pith and knots was conside rably decreased than that of clear lamina as shown Table 13. 3.3 The shear strength of the FPL block of the straight laminated wood constructed by the same species which were glued with urea adhesives was more than twice the limited adhesion strength, thus it makes possible to use it for interior constructional stock.

• Korean journal of applied entomology
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• v.42 no.2
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• pp.169-171
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• 2003

The life history and natural enemies of Coleophora obducia Meyrick which is a defoliating pest of Larix leptolepis were studied mainly in Chungchongbuk Province. Larix leptoiepis was the only host plant of this pest. Coleophora obducia had one generation per you and the adults emerged from mid May to late May with a peak emergence around May 14th. The mean number of eggs in an ovary was 44.5 and most females oviposited one egg on each needle. The duration of the egg stage was about two weeks. Larvae passed the winter in a pouch made by spinning the needles. Pupation began in the late April, and the pupal period was two weeks on average. The natural enemies observed were parasitoids and predators.

• Korean Journal of Ecology and Environment
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• v.46 no.2
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• pp.241-250
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• 2013

Developmental process of vegetation over years after afforestation was analyzed in the Japanese larch (Larix kaempferi) plantations with different stand ages. The height and diameter of Japanese larch increased rapidly until 24 years after afforestation and tended to be blunted thereafter. The density of Japanese larch was similar with each other in the 8 and 17 years old stands but was reduced greatly in the 24 years old plantation and changing little thereafter. The floristic composition of the Japanese larch plantation did not show any clear trend depending on stand ages. The differences of species composition among plantation themselves with different ages were bigger than those between plantations and the reference stands, Mongolian oak (Quercus mongolica) stands. Japanese larch plantations showed a trend of succession to native vegetation dominated by Mongolian oak based on the results of analysis of frequency distribution by diameter class of major tree species. Species richness and diversity of all plantations were higher than those of the reference vegetation. As were shown in the above mentioned results, it can be evaluated that Japanese larch plantations practiced in the level of the functional restoration achieved successful restoration based on the floristic composition similar to the reference vegetation, the successional trend toward native vegetation, and higher species diversity compared with the reference vegetation.

• Journal of the Korean Wood Science and Technology
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• v.41 no.3
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• pp.247-257
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• 2013

This study was to investigate the antifungal activity of Larix kaempferi essential oil against dermatophytes, Epidermophyton floccosum, Trichophyton mentagrophytes and Trichophyton rubrum. The active components of L. kaempferi against dermatophytes were determined (characterized by GC-MS), and the morphological changes of the dermatophytes exposed to the L. kaempferi essential oil were observed by electron microscope. Main component of L. kaempferi essential oil was (-)-bornyl acetate. In antifungal activity tests, MIC of L. kaempferi crude oil was 125 ppm on every fungi and 100% (agar dilution method) at more than 500 ppm. By using SEM and TEM, the fungal morphology of E. floccosum exposed to the L. kaempferi essential oil was different from that of normal hyphal morphology. Hyphae exposed to the L. kaempferi essential oil was damaged with distorted and collapsed surfaces. In addition, there were destruction and disorganization of organelles in cytoplasm and collapse of cell membrane. Active antifungal components from L. kaempferi essential oil were identified as terpene alcohol compounds like (-)-${\tau}$-muurolol, (+)-terpinen-4-ol, ${\alpha}$-terpineol, and ${\alpha}$-cadinol.

• Journal of the Korean Wood Science and Technology
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• v.34 no.1
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• pp.1-6
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• 2006

Radial variations of resin canals in Pinus koraicnsis and Larix kaempferi which were cultivated-commercial trees in Korea, were examined to understand the characteristics of wood with light microscopy. Both species showed significant differences in the number of vertical resin canals along the radial direction from pith to bark. In Larix kaempferi, the diameters of horizontal resin canals and the number of epithelial cells showed a clear variation in radial direction. Namely, significant differences in the characteristics of the resin canals and epithelial cells were found in juvenile and adult woods. Consequently, it was concluded that the characteristics of resin canals can he used to estimate the wood quality.

• Journal of the Korean Wood Science and Technology
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• v.4 no.1
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• pp.21-27
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• 1976

This study was carried out in order to obtain the effect of active alkali concentration. Sulfidity 25%, maximum temperature 170$^{\circ}C$, cooking time 3hrs., liquor to wood ratio 5 : 1 in the kraft cooking conditions were maintained. Active alkali concentration were varied at intervals of 3% between 12% and 24%. The rates of de lignification increased with an increase in active alkali concentration and beatability, brightness, and strength of pulp also improved. The total pulp yield trand to decrease with an increase of active alkali concentration. The maximum screened pulp yield were obtained between 18% and 21% A.A.. Therefore, the optimum active alkali concentration was 18~21%.

• Journal of the Korean Wood Science and Technology
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• v.8 no.2
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• pp.6-8
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• 1980

Japanese larch veneer, Cryptomeria veneer and japanese cypress veneer were peeled with condition of nose bar pressure at 5%, 10%, 15%, to find the optimum nose bar pressure. 1. Optimum nose bar pressure was 15% in 2mm thickness veneer of japanese larch. 2. Optimum nose bar pressure was 5% in 2mm thickness veneer of Cryptomeria. 3. Optimum nose bar pressure was 15% in 2mm thickness veneer of japanese cypress.

• Journal of the Korean Wood Science and Technology
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• v.37 no.6
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• pp.531-536
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• 2009

Radial variations of ray spacing and frequency of biseriate ray were examined in the woods of most commercially important Korean softwood species of Pinus koraiensis and Larix kaempferi. Ray spacing, or ray number per mm in cross section, averaged 4.6 and 9.0 in Pinus koraiensis and Larix kaempferi, respectively. Thus, rays of Larix kaempferi appeared to be more closely arranged than those of Pinus koraiensis. Ray spacing was the densest around pith, and then slowly decreased toward bark. In tangential section, biseriate ray frequency of Larix kaempferi was higher than that of Pinus koraiensis. Biseriate ray was designated, based on the number of cells of biseriate portion in vertical extent, as the type of B+1 (one cell high), B+2 (two cells high), and so on. The dominated type was B+1 in Pinus koraiensis but B+2 in Larix kaempferi. The biseriate ray types of B+3, B+4, and B+5 were occasionally found in earlywood. Interestingly, even B+6 and B+7 types were observed in Larix kaempferi. In conclusion, it was considered that ray spacing could be used for separating juvenile wood from adult wood. Also, characteristics of ray spacing and biseriate ray might be used for identifying these two species.