• Applied Chemistry for Engineering
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• v.35 no.1
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• pp.29-36
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• 2024

The fire risk and fire safety of four types of wood were comprehensively evaluated according to Chung's equation-XII. White ash, willow, fraxinus mandshurica, and sagent cherry trees were selected as test specimens. A cone calorimetery (ISO 5660-1) was used to examine the combustion characteristics of the test piece, and finally, the fire risk rating (FRR) was predicted using the fire risk index-XII (FRI-XII). The predicted fire performance index-X (FPI-X) and fire growth index-X (FGI-X) ranged from 469.03 to 1109.73 s²/kW and 0.0009 to 0.0280 kW/s², respectively. Additionally, the fire performance index-XI (FPI-XI) and fire growth index-XI (FGI-XI) ranged from 0.41 to 0.97 and 1.11 to 3.11, respectively. The fire risk index-XII (FRI-XII), representing a fire risk rating, showed that the fire risk of frasxinus mandsurica tree (FM) was very high at 7.60 (fire risk rating: D). And it was compared with Chung's equation-IX, fire risk index-IX (FRI-IX). The fire risk ratings according to FRI-IX and FRI-XII were generally high for willow and frasxinus mandsurica trees. Additionally, the results of FRI-XII and FRI-IX had a similar relationship, and the size of each fire safety rating closely matched each other.

• Korean Journal of Environmental Agriculture
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• v.29 no.2
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• pp.206-213
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• 2010

The aim of this study was to provide basic informations for restoring a habitat of Nannophy pygmaea Rambur. Environments and flora of the habitats were investigated in Youngdong, Sanbuk, and Nongam South Korea. The habitats were abandoned paddy fields with tree-unshaded space and with the water depths of about 2 - 10 cm all the year round. The water quality was recorded 5.44 - 7.33 in pH, 0.017 - 0.480 dS/m in EC, 1.34 - 4.94 mg/L in T-N and 0.06 - 0.46 mg/L in T-P. The pH and EC showed a wide range values, and T-N and T-P showed a high values comparatively. This result implies that a water quality does not important as the condition for a habitat of the species. A total of 86 vascular plant taxa belonging to 35 families, 60 genera, 67 species, 2 subspecies, 14 varieties and 3 forma were recognized in the habitats. Twenty two species (25.6%) overlapped among the habitats; Equisetum arvense, Salix koreensis, Persicaria thunbergii, Stellaria alsine var. undulata, Hypericum laxum, Kummerowia striata, Epilobium pyrricholophum, Oenanthe javanica, Mosla dianthera, Utricularia vulgaris var. japonica, Plantago asiatica, Eupatorium lindleyanum, Juncus diastrophanthus, J. effusus var. decipiens, J. papillosus, Aneilema keisak, Alopecurus aequalis, Arthraxon hispidus, Carex dickinsii, Cyperus sanguinolentus, Eleocharis acicularis for. longiseta and E. congesta. Biological type was determined to be HH-R5-D4-e(t) type; HH 39 taxa (45.3%), R5 42 taxa (48.8%), D4 59 taxa (68.6%) and e (or t) 23 taxa (26.7%).

• Journal of Korean Society of Forest Science
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• v.88 no.1
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• pp.93-100
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• 1999

This study has been carried out to estimate aboveground and soil carbon contents in an average 39-year-old Quercus mongolica and 40-year-old Quercus variabilis stands in Chungju, Chungbuk. Ten sample trees were cut in each forest and soil samples were collected. Aboveground carbon content was estimated by the equation model $Wt=aD^b$ where Wt is oven-dry weight in kg and D is DBH in cm. Total aboveground carbon content was 48.85tonC/ha in Quercus mongolica stand and 57.49tonC/ha in Quercus variabilis stand. The proportion of each tree component to total aboveground carbon content was high in order of bolewood, branches, bolebark, and leaves in the two forests. Aboveground net primary production was estimated at 5.88tonC/ha in Quercus mongolica stand and 5.12tonC/ha in Quercus variabilis stand. Soil carbon content was 67.0tonC/ha in Quercus mongolica stand, 67.8tonC/ha in Quercus variabilis stand, and 54.7tonC/ha in Pinus densiflora stand. There was no significant difference in soil carbon content among the three forests.

• Journal of Korean Society of Forest Science
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• v.105 no.1
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• pp.48-62
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• 2016

This study was conducted to classify forest vegetation structure and stand feature of Mt. Deogyusan National Park from Hyangjeukbong to Jungbong, 48 plots were surveyed. The type classification of the vegetation structure was performed with Z-M phytosociological method. As a result, Quercus mongolica community group was classified into the Picea jezoensis community, Carpinus cordata community and Tilia amurensis community in community unit. P. jezoensis community was subdivided into Deutzia glabrata group and Viburnum opulus var. calvescens group in group unit. D. glabrata group was subdivided into Acer mandshuricum subgroup and Ribes mandshuricum subgroup and V. opulus var. calvescens group was subdivided into Hemerocallis dumortieri subgroup and Prunus padus subgroup in subgroup unit. In the result of estimating the importance value, it constituted Q. mongolica (23.9%), Abies koreana (14.7%), Taxus cuspidata (10.2%), P. jezoensis (8.2%) and Betula ermanii (7.4%) in tree layer. It constituted Acer komarovii (18.6%), Acer pseudosieboldianum (18.4%) and Q. mongolica (8.9%) in subtree layer. It constituted Rhododendron schlippenbachii (20.7%), A. pseudosieboldianum (17.4%) and Symplocos chinensis (8.5%) in shrub layer. Indicator species analysis of vegetation unit 1 was consisted of Hydrangea serrata, Fraxinus mandshurica and D. glabrata that species prefer moist valley in subalpine or rocks. In the results of analyzing the species diversity, vegetation unit 1, 4 and 5 represented that there were different and complex local distributions. As in the similarity between the vegetation units, the vegetation units 1, 2, 3 and 4 represented high with 0.5 or above. It represented that there wasn't no differences on composition species in vegetation units.

• Korean journal of applied entomology
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• v.4
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• pp.59-64
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• 1965

This study was planned to find out the effects of several food-plants on the pupal weight and the number of eggs in the ovary of the fall webworm, Hyphantria cunea $D_{RURY}$. The larvae were separately reared on different food-plants in the Petri dish. Four to six day old pupae were used for the study of the pupal weight. The number of eggs in the ovary was counted under the binocular dissecting microscope. The loaves of the food-plants were sampled on Juiy 16, and analyzed by Kjeldahl method for the determination of total nitrogen content. The results obtained in this study were as follows; (1) The pupal weights were highly different according to the species of plants and sexes. The greatest pupal weight found in the pupae reared on the mulberry and the least one in the pupae reared on the apple tree. The weight female pupae was greater than that of male pupae in every case. (2) The number of eggs in the ovary was positively correlated to the pupal weight. (3) The nitrogen content of the food-plants used in this experiment was varied with the species of the plants. However, the nitrogen content of the food-plants was not significantly correlated to the pupal weight and the number eggs in the ovary.

• Journal of Korean Society of Forest Science
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• v.83 no.2
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• pp.221-228
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• 1994

Respitation and growth rates of leaves, branches, stems and roots of 2 to 11-yr-old red pine trees(Pinus densiflora) were examined and applied to Thornley's growth equation, $$R=(\frac{1-Yg}{Yg})\frac{dW}{dt}+mW$$. The conversion efficiency of substrates(Yg), maintenance respiration coefficients(m), relative growth rates(${\mu}$) were estimated. The efficiency of conversion of substrates (Yg) was 0.3637g/g dw/yr and the maintenance respiration coefficient(m0 was 0.094g/g dw/yr. The relative growth rate(${\mu}$) was remarkably reduced with age from 0.90(2-year-old) to 0.33:11 year-old). The Ratio of gross respiration(R) per gross photosynthesis(Pg), R/Pg showed the range of 0.6~0.7 and annually 64% of Pg was spent for constructive respiration. The 3.4% of dry weight of whole tree was spent for maintenance respiration.

• Journal of Life Science
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• v.27 no.5
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• pp.561-566
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• 2017

Dendropanax morbifera Lev. is known in Korea for its golden sap and medicinal properties. The many biological activities of the leaf and stem extracts suggest that this tree could be a valuable source of medicinal compounds for the treatment of various ailments such as dermatitis, migraines, dysmenorrhea, muscle pain, and infectious diseases. However, there is little information on the composition and biological activity of the volatile fraction of D. morbifera. Therefore, in this study, the volatile compounds in leaves, stems, and sap of D. morbifera were isolated using solvent and supercritical fluid extraction (SFE), and analyzed by gas chromatography/mass spectrometry to reveal their chemical composition and identify potential compounds of interest. Fifteen compounds were identified in the leaf extracts, whereas 29 and 3 compounds were identified in the stem and sap extracts, respectively. The volatile profiles obtained using solvent and SFE differed. Esters and aromatic hydrocarbons predominated in the solvent extract of leaves and SFE extract of stems, whereas the solvent extract of stems and SFE extract of leaves contained terpenoids. Limonene, ${\alpha}$-pinene, and ${\beta}$-myrcene were identified in the volatile extract of sap, with limonene representing 96.30% of the total peak area. In addition, the antiproliferative effects of the solvent extracts of leaves and stems were evaluated, revealing that these solvent extracts were particularly effective in decreasing the proliferation of HepG2 cells.

• Journal of Korean Society of Forest Science
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• v.86 no.4
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• pp.509-520
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• 1997

This is a report on the early vegetation, plant community structure, and secondary succession of cut and uncut sites of burned areas in Mt. Gumo-sun. The forest fire occurred on April, 1994 and the pine forest and its floor vegetation were burned down. The investigation was carried out from April, 1995 to October, 1996. The results are summarized as follows : The floristic composition of cut and uncut sites of burned area and unburned area were composed of 32, 36, and 34 kinds of vascular plants respectively. The biological spectra showed the $H(G)-D_1-R_5-e$ type, $H(M)-D_1-R_5-e$ and $M(N)-D_1-R_5-e$ in cut, uncut, and unburned site respectively. The dominant species based on $SDR_3$ of the cut site were Miscanthus sinensis var. purpurascens(100.00). Caret humilis(52.27), Quercus serrata(51.19) and Lysimachia clethroides(39.40), however, in the uncut sites the dominant species were Quercus acutissima(56.91), Pinus densiflora(26.83) in the tree layer, Quercus serrata(50.43), Lindera glauca(40.51), Lespedeza bicolor(37.85) in the shrub layer, and Miscanthus sinensis var. purpurascens(72.27), Pteridium aquilium var. latiusculum(60.92), Carex humilis(63.63) in the herb layer. Pinus densiflora(99.88), Miscanthus sinensis var. purpurascens(82.74), Quercus serrata(77.47) and Carex humilis(74.02) were dominant in the unburned site. The species diversity(H) and evenness index(e) were 1.05, 0.70 and 1.32, 0.85 in the cut and uncut site, respectively and 0.22, 0.63 in the unburned site. Dominance index(C) was 0.15, 0.06 and 0.96 in the cut, uncut site and unburned site, respectively. Degree of succession(DS) was 345.19, 747.47 and 674.34 in cut, uncut and unburned site, respectively. The index of similarity(CCs) was 0.66 between cut and uncut sites, 0.50 between unburned and cut sites and 0.61 between unburned and uncut sites. The amount of exchangeable sodium, calcium, magnesium and soil pH were increased, but the amount of organic matter, available phosphous, total nitrogen, total carbon and exchangeable potassium were decreased in cut site after fire.

• The Korean Journal of Ecology
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• v.19 no.5
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• pp.417-430
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• 1996

This study was conducted to investigate the developmental process of plant community during the secondary succession and the dynamics of soil properties in the burned and unburned areas of Mt. Ch’oly-san. Owing to the forest fire occurred on April, 1989, the red pine(Pinus densiflora) forest and its floor vegetation were burned down. The floristic composition of burned and unburned areas were composed of 53 and 49 species of vascular plants, respectively. The dominant species based on SDR4 of the burned sites were lespedeza cyrtobotrya (89.62), Miscanthus sinensis var. purpurascens (62.50), and Carex humilis (58.73), Quercus serrata (43.33). In contrast, Pinus densiflora (83.56), Lespedeza cyrtobotrya (55.57), Miscanthus sinensis var. purpurascens (51.88) and Carex humilis (50.41) were dominant in the unburned area. The biological spectra showed the $H-D_1-R_5-e$ type in both the burned and unburned areas. The indices of similarity ($CC_S$) between the two areas were 0.74. Degree of succession (DS) was 604 in the burned area and 802 in the unburned area. From these facts, it is assumed that the succession is rapidly progressing because of the recovery of vegetation. The species diversity ($\={H}$) and evenness index(C) in the burned and unburned areas were 0.15 and 0.18, respectively. Red pine tree did not resprout after scorch by the forest fire, but Lespedeza, Quercus, Rhododendron, Albizzia, and Zanthoxylum resprouted from the roots and trunks after the forest fire. It seems that these species are the fire-resistant species. Soil properties such as soil pH, content of organic matter, available phosphous, total nitrogen, tatal carbon, exchangeable potssium, sodium, calcium, and magnesium increased due to forest fire. These results suggest the intensity of forest fire in the study area was relatively weak. Monthly changes of soil properties were of little significance except for some cases.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.15 no.5
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• pp.207-212
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• 2015

Continuous, high-quality supply of electrical energy is the backbone of any modern economy. Any equipment operating at a power station must be reliable and safe. All major power supply components such as transformers, cables, generators, and switchgear need to be kept in perfect operating condition. The lifetime of power cables, used as the main means of transferring electric power, is understood to be about 30 years, from the time of manufacturing. The dielectrics between two conductors of a cable must be able to withstand electrical stresses from high-voltage input. This condition should be verified throughout the lifetime of the cable system. Several techniques, such as VLF-tan${\delta}$, partial discharge, and insulation resistance are used in order to determine the operating conditions of cables. In this paper, we present our work on insulation resistance to diagnose cables in operation at the Western Power station in Taean, Chungcheong Namdo Province, South Korea. As a result we have found cables the life time of which is 38 years.