• Journal of the Korean Wood Science and Technology
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• v.25 no.1
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• pp.23-27
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• 1997

Alkali-soluble extracts were prepared from barks of Japanese larch(Larix leptolepis). Siberian larch(Larix gmelineii) and Radiata pine(Pinus radiata) The effect of various factors, such as particle size, liquor ratio, extraction temperature, and reaction time, on the extracts yield was investigated. Particle sizes affected the alkali-soluble extracts; the finer the particle size, the higher extracts and extract efficiency. High temperature and high liquor ratio were more effective. In the range of 0.25% to 1% NaOH concentration, alkali extracts were increased with the increasing alkali concentration. However, extract yields were leveled off above 0.5% alkali concentration. Extractions with NaHCO3 were almost equivalent to those of NaOH extraction. 1% NaOH and 1% NaHCO3 resulted in the highest yields of alkaline extracts. Extracts from Japanese larch were lower than those from Siberian larch and Radiata pine barks. Siberian larch bark was the best raw material for tannin adhesives, because its extractive yield was higher than those of the other barks. Concerning pH of alkaline media during extraction, small increases of the extract yields were resulted at range of pH 7 to pH 9, while a large increases from pH 9.0 to pH 12. This phenomenon is attributed to higher alkalinity.

• Journal of the Korean Wood Science and Technology
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• v.25 no.1
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• pp.28-36
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• 1997

Several thick board and dimension lumbers of Japanese larch(Larix leptolepis), Dahurian larch(Larix gmelini) and radiata pine(Pinus radiata) air-dried in four different seasons to compare air-drying process. Patterns of air-drying curves were influenced by climatological conditions and limber thickness. The initial drying rates of summer were the highest, followed those of fall, spring and winter. The drying times to equilibrium moisture contents for four seasons were nearly the same except for winter. However, the drying time for winter required twice more time than the other seasons. The drying time of dimension lumbers required 1.3 times more than boards. The final moisture contents were lowest during spring, highest during winter and similar between summer and fall.

• 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 Environment and Ecology
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• v.25 no.1
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• pp.31-36
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• 2011

To provide the basic information about slope stability analysis, tensile force and strength of tree roots like Pinus koraiensis, Larix leptolepis, Pinus densiflora, Quercus mongolica, and Alnus japonica were measured and analyzed. As a result, tensile force increases in forms of involution of root diameter. The mean tensile strength of roots like P. koraiensis, L. leptolepis, P. densiflora, A. japonica and Q. mongolica were calculated as $165.38kgf/cm^2$, $172.78kgf/cm^2$, $176.25kgf/cm^2$, $214.29kgf/cm^2$ and $224.19kgf/cm^2$ respectively. It was shown that tensile strength decreasing tendency as root diameter increases. Also, recalculated soil shear strength by tensile strength of the roots like P. koraiensis, L. leptolepis, P. densiflora, A. japonica and Q. mongolica were $0.099kgf/cm^2$, $0.104kgf/cm^2$, $0.106kgf/cm^2$, $0.129kgf/cm^2$ and $0.135kgf/cm^2$ respectively.

• The Korean Journal of Ecology
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• v.17 no.1
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• pp.11-22
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• 1994

The understory vegetation of a Chamaecyparis obtusa plantation is relatively sparse at a valley in Sangkwan-my6n, Wanju-gun, Chiinbuk, Korea, and that of the pure C. obtusa plantation is more sparse than in the C, obtusa-Larix leptolepis plantation. In order to investigate the causes of this difference, this study was carried out both in the field and in the laboratory. Total of 109 taxa, comprising 90 genera and 53 families, were identified in the plantation. But the average number of species above 10% frequency was only 27, and both the number of species and plants per quadrat in the pure C. obtusa plantation were lower than those in the C, obtusa-L. leptolepis plantation. Light intensity, soil pH, and the difference of soil minerals were supposed to be parts of the causes. Soils, litter extracts of C. obtusa and L. leptolepis, and leachates collected by vermiculite beneath C. obtusa canopy for 1 year were tested for the effect on germination and seedling growth of both inside species and outside species in the laboratory. Germination and seedling growth of outside species were more suppressed than those of inside species. Therefore it was found that allelopathic effect of C. obtusa would be responsible for the sparse understory vegetation in the C. oblusa plantation.

• Journal of Korean Society of Forest Science
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• v.88 no.4
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• pp.541-554
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• 1999

The objectives of this study were to examine the amount of nutrient input by throughfall and stemflow, and the nutrient dynamics by throughfall, stemflow and soil solution among Piuns koraiensis, Larix leptolepis and hardwood forests including oaks at Kwangju-Gun, Kyonggi-Do. A total amount of rainfall during the study period was 1410.1mm. Of the total rainfall, 85% was from throughfall at the L. leptolepis stand, 84.5% at the thinned P. koraiensis stand, 83.2% at the unthinned P. koraiensu stand and 81.2% at the hardwood stand, showing greater throughfall at the conifer stand than at the hardwood stand. Stemflow showed 2.7% of rainfall at the hardwood stand, 1.3% at the unthinned P. koraiensis stand, 1.2% at the thinned P. koraiensis stand and 0.8% at the L. leptolepis stand, showing greater stemflow at the hardwood stand than at the conifer stand. Ion concentration of stemflow was greater than those of rainfall and throughfall. The conifer stand showed higher ion concentration than the hardwood stand both for cation and anion. The ion concentrations of throughfall and stemflow were higher in the descending order : $NH{_4}^+$-N > $K^+$ > $K^+$ > $Na^+$ > $Mg^{2+}$ for cations and $SO{_4}^{2-}$ > $NO{_3}^-$-N > $Cl^-$-N for anions. After the precipitation passed through the canopy, $K^+$ increased most at the hardwood stand, whereas $NH{_4}^+$-N did most at the P. koraiensis and L. leptolepis stands. The ion concentration of soil solution was higher in the descending order : $Ca^{2+}$ > $Mg^{2+}$ > $Na^+$ for cations and $NO{_3}^-$-N > $Cl^-$ > $SO{_4}^{2-}$ for anions. $NH{_4}^+$-N and $K^+$ seemed to be supplied primarily from atmospheric deposition while $Ca^{2+}$, $Mg^{2+}$ and $Na^+$ from weathering.

• Journal of the Korean Wood Science and Technology
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• v.15 no.4
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• pp.12-17
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• 1987

To extract arabinogalactan from larch (Larix Leptolepis), chips immersed with water(20-$90^{\circ}C$) for 1hr, were defiberized by refiner. The liquors were recovered and purified to pure arabinogalactan by ion exchange resin(IRC-50 a. IR-45) or MgO. Additionally the optimal condition in purification with MgO was also investigated. 1. The amounts of solids(crude sugars) and pure arabinogalctan in solids are 8.6-11.3% and 7.3-8.5%(raw material = 100), respectively. 2. Phenolic materials in crude sugars are removed up to 96-89% by ion exchange resin and 94-88% by MgO, while recovery yields of pure arabinogalactan are 81-75% on purification with ion exchange resin and 91-87% on purification with MgO. 3. The optimal conditions of purification with MgO are the addition of 35mg MgO/0.5g of crude sugars, 45 minutes at $70^{\circ}C$, or 25 mg MgO, 30 minutes at $85^{\circ}C$.

• The Korean Journal of Ecology
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• v.15 no.4
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• pp.411-431
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• 1992

The present study was undertaken to classify and describe the vegetation around andong dam area, kyong-buk, korea$(36^{\circ}\;35^{\prime}\;N, \;128^{\circ}\;47^{\prime}\;E)$ by methods of the ZM school of phytosociology. The investigations were carried out in the plot. The homogeneous part of forest and grass communities was analyzed by recording the combined scale of cover-abundance and sociability of all species found in the plot. The community data obtained were classified into two associations and seven communities; festuco onvinae-pinetum densiflorae assoc. nov., quercetum variabili-serratae, quercus acutissima community, larix leptolepis, populus tomentiglandulosa, acer canadensis, prunus spp. afforestations, robinia pseudo-acacia-commelina communis community and acer palmatum cv. afforestation. The grass vegetation was divided into six associations and seventeen communities; lactuco indicae- humuletum japonicae, eragrostio ferruginei-plantaginetum asiaticae, polygonetum thunbergii, phragmitetum japonicae, eragrostio ferruginei-plantaginetum asiaticae, polygonetum thunbergii, phragmitetum japonicae, artemisio-potentilletum chinesis, eleusinetum indicae, amorpha freticosa, artemisia princeps, achyranthes fauriei and other fourteen communities. amoung the above vegetationship of the vegetation units with their environments was outlined.

• Journal of the Korean Institute of Landscape Architecture
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• v.19 no.3
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• pp.27-40
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• 1991

For the establishment of district planning in natural parks, vegetationin the most significant point. Consequently, district plan should be made basically under phytosociological investigations. The purpose of this paper is to conserve vegetation in the district planning at natural park(Nam Han San Sung provincial natural park). The result of vegetation survey are as follows : As an actual vegetation 13 communities are recognized. Those are Quercus mongolica-Carpinus laxiflora community, Quercus mongolica-Rhododendron schlippenbachii community, Quercus serrate community, Betula platyphylla var. Japonica community, Quercus dentata community, Quercus mongolica-Pnuus densiflora community, Quercus acutissima community, Robinia pseudo-acacia community, Alnus hirsuta community, Castanea crenata community, Quercus variabilis community, Pinus densiflora community, Pinus rigida community, weed community on cultivated land(Form land), Larix leptolepis reforested land, cut over area and non-vegetation area. The grade of vegetation naturalness was divided into five degrees by characteristics of actual vegetation. I intended to make zoning plan for protection of vegetation with a special attention to the grade of vegetation naturalness and I discussed the necessity of the improvement of existing district plan. District plan was proposed as Fig. 5.

• Journal of the Korean Chemical Society
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• v.15 no.6
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• pp.370-377
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• 1971

The Carbon-14 content in surface air at Seoul, Korea, was measured from February 1970 to August 1971 and a Larix Leptolepis, Gordon tree (Ip-Gal Namu) grown at Kwang-Nung, Kyunggi-Do, Korea, having 37 growth rings, was assayde for $^{14}C$. From the results of the surface air study, it was calculated that during the above period the inventory of excess $^{14}C$ in the atmosphere decreased with a half-time of 4.6 years. The overall yearly decrease was also checked. The tree-ring study showed that the tree's atmosphere was affected by $^{14}C$ from nuclear tests after 1956. In one study, atmospheric $CO^2$ samples were collected bi-monthly by the absorption of $CO^2$ in alkaline hydroxide solution. In the other, 5 year annual growth rings were assayed for radiocarbon. For the radioactivity measurement, carbon atoms in samples were converted to carbon atoms of benzene. The resulting benzene was taken as primary solvent for liquid scintillation counting.