• 한국방재학회:학술대회논문집
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• 2008.02a
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• pp.149-152
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• 2008

This study is the result between the variation of fuel moisture and the risk of forest fire through measuring the change of moisture containing ratio on-site and its average analysis for fallen leaves layer, humus layer, and soil layer in the forest. The measurement was performed on six days from the day after a rainfall. The fuel moisture on-site was measured on the day when the accumulated rainfall was above 5.0mm, and the measurements was 2 times in spring and 1 time in fall. From the pine forest which were distributed around Samcheok and Donghae in Kangwondo, three regions were selected by loose, medium, and dense forest density, and the fuel moisture was measured on fallen leaves layer, humus layer, and soil layer in the forest. for six days from the day after a rainfall. The study showed that the moisture containing ratio converged on 3 - 4 days in spring and fall for fallen leaves layer, and the convergence was made more than six days in spring and fall for the humus layer. In the other case of soil layer, the variation of moisture containing ratio after rainfall was not distinguishable regardless of season.

• Korean Journal of Microbiology
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• v.52 no.2
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• pp.175-182
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• 2016

In this study, we isolated aromatic compounds (lignin polymers) utilizing bacteria in humus layer of oak forest and investigated phylogenetic characteristics and correlation with major bacterial populations in the humus layer by pyrosequencing. Forty-two isolates using aromatic compounds such as p-anisic acid, benzoic acid, ferulic acid and p-coumaric acid were isolated and phylogentic analyses based on 16S rRNA gene sequences showed that the isolates belonged to the genus Rhizobium, Sphingomonas, Burkhorlderia, and Pseudomonas. Among these, Burkhorlderia species which belong to Betaproteobacteria class occupied 83% among the isolates. The bacterial populations in humus layer of oak forest were characterized by next generation pyrosequencing based on 16S rRNA gene sequences. The humus sample produced 7,862 reads, 1,821 OTUs and 6.76 variability index with 97% of significance level, respectively. Bacterial populations consist of 22 phyla and Betaproteobacteria were the major phylum consisting of 15 genera including Burkholderia, Polaromonas, Ralstoria, Zoogloea, and Variovorax. Approximately fifty percentage of them was Burkholderia. Burkholderia as the majority of population in the humus was considered to play a role in degrading lignin in humus layer of oak forest.

• Journal of the Korean Institute of Landscape Architecture
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• v.31 no.6
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• pp.95-103
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• 2004

A turfgrass rootzone foundation is one of the important iufluences on the growth of cool-season turfgrass such as Kentucky bluegrass, which is usually grown on korean golf courses and athletic fields in Korea. This study was carried out to evaluate the growth of Kentucky bluegrass on 4 types of turfgrass root-zone foundations: a 2cm thickness of Sand 90%+Peat humus 8%+Zeolite 2% mixture on a subsoil base (C), a 20cm thickness of Sand 90%+Peat humus 8%+Zeolite 2% mixture (S), a 20cm thickness of Sand 45%+fine sand(a sort of Bomyungsa) 45%+Peat humus 8%+Zeolite 2% mixture (S+F), and a 20cm thickness of Sand 45%+fine sand(a sort of Bomyungsa) 45%+Peat humus 8%+Zeolite 2% mixture on a 20cm thick drainage layer (S+F(G)). Visual ratings of Kentucky bluegrass on the C foundation were low throughout the experiment when compared to S, S+F, and S+F(G) foundations, which contained high contents of sand with a high water infiltration rate. However, poor growth of Kentucky bluegrass in the summer of 1991 on the S foundation was likely to be caused by a too high water infiltration rate (185.8cm/hr). The growth of Kentucky bluegrass on the S+F(G) was good while the growth was a little weak at the developing stage on the S +F foundation. If the cost had to be considered when constructing golf courses and athletic fields, The S+F foundation without the drainage layer would be the best choice in terms of low cost and good quality of Kentucky bluegrass compared to the S+F(G). In this result, the infiltration rate was regarded as the most influential factor to the growth of Kentucky bluegrass on rootzone foundations.

• Journal of the Korean earth science society
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• v.33 no.4
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• pp.320-328
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• 2012

To investigate geomorphic development of alluvial plains and climatic environment change during the late Holocene carbon dating, soil organic carbon analysis and humus analysis of sediments from alluvial plain of Hampyeongcheon basin were performed. The lowest peat layer was formed under warm and humid climates, which is considered to correspond to the Atlantic period in the Holocene. Yellowish brown sandy clay layer was deposited in the natural levee, which we think were deposited in the generally warm and dry climates. The carbon dating age is 1,879-1,532 BC, and this period correspond to the Sub-boreal period in the Holocene. Light brown clay layer is assumed to have been deposited in transitional environment from the natural levee to the back marsh. The climatic environment was warm and humid, which is considered as transitional period from the Sub-boreal to the Sub-Atlantic in the Holocene. Light yellowish brown and light brown clay layer of the upper part are regarded as sediments of the back marsh. Light yellowish brown clay layer was deposited in the cold and dry climates, which is considered to correspond to the Sub-Atlantic period in the Holocene. Light brown clay layer was deposited in the warm and dry climates. The carbon dating age is 211-427 AD, this period corresponds to the Post Roman Warm Period in the Holocene.

• Journal of the Korean earth science society
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• v.33 no.6
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• pp.510-518
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• 2012

The Holocene climate change has been studied based on humus analysis of sediments that came from the Nam River basin in the Jinju, Gyeongnam. Humus and soil organic carbon analyses were performed to interpret the climate change and OSL dating and radiocarbon dating were conducted to determine the age of the sediments. The age determinations revealed that the sediments were formed approximately from $10,000{\pm}100$ yr. BP to $4,370{\pm}50$ yr. BP (2,970 BC) The deposits were classified into five layers based on sediments color and texture, and the climate change of each layer has been interpreted. The general climate was found out to be warm. The study result illustrated that section I was the lowest layer and section V the highest among the five surveyed sections. One the other hand, relatively cold events were detected in the sections ranging from I and II to III in terms of temperature. In term of humidity, sections II and III are estimated to have been relatively dry. Sections IV and V were relatively warm and dry, and the section IV tends to be warmest of the entire sedimentary. In addition, there is a tendency that the total soil organic carbon shows relatively high values under the cooler and humid climatic condition.

• Fire Science and Engineering
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• v.24 no.6
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• pp.1-6
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• 2010

A smoldering ground fire can be a probable cause of reignition of surface fire when transmitted from Fermentation layer to Humus layer with temperature higher than that of ignition. Purpose of this paper is to identify experimental methodology on the potential risk of a smoldering ground fire, which is similar to the real surface fuel bed, and its combustion characteristics. The fuel model designed in this study is composed of 3 layers such as Litter layer, Fermentation layer and Humus layer and 8 Thermocouples are set through 3 layer at each boundary and in between to detect the temperature change and duration of smoldering and propagation velocity. As a result, it was observed that ignition conditions in the boundary between L layer and F layer determined transmission and non-transmisstion to F-H layer. In addition, range of critical humidity at which a smoldering ground fire was transmitted in a material layer was 33~44% and when temperature exceeds $350^{\circ}C$, likelihood of transmission of a smoldering ground fire was high. In the research, the experimental model for multi-layer smoldering ground fire is suggested and information about propagation of smoldering fire, possibility of reignition according to moisture content, propagation velocity and temperature change are obtained, Also, the built-up methods were established to help analyze basic characteristics of smoldering ground fire.

• Fire Science and Engineering
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• v.26 no.1
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• pp.49-60
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• 2012

The change in fuel moisture in accordance with the number of days after rainfall is an important factor in predicting forest fire dangers and supporting forest fire rangers. Therefore, in order to clear up these forest fire occurrence conditions, forest fire danger levels for surface fuel 0.6 cm or lower, 0.6~3.0 cm, 3.0~6.0 cm, and 6.0 cm or above by fallen leaves layer, humus layer, soil layer, and diameter after rainfall of 5.0 mm and higher in accordance with tree density in 2008, 2009 Spring/Autumn Young Dong region have been analyzed. Research showed an approximate 17 % fuel moisture which is a dangerous forest fire occurrence level after 5 days from rainfall in medium-density areas and 3 days after rainfall in loose-density areas of Spring time in the fallen leaves layer. On the other hand, the humus layer showed a 40 % or higher fuel humidity even after 6 days from rainfall regardless of the season, while the upper and lower parts of the soil layer had a little change. In loose-density areas with 0.6 cm or less surface fuel per diameter in Spring time, the fuel humidity displayed a dangerous level in fire forest occurrence after 3 days, and 4days in medium-density areas, and for loose-density areas with 0.6~3.0 cm surface fuel per diameter in Autumn time it showed a dangerous level in forest fire occurrence after 3 days, and for medium-density areas, 5 days. In the case of 3.0~6.0 cm of fuel moisture per diameter in both Spring and Autumn times, even after 6 days, low and medium-density areas showed that they maintain fuel moisture and therefore the dangers of forest fires were very low, and in the case of 6.0 cm or higher, it showed 25 % or higher fuel moisture even after 6 days from rainfall regardless of the season.

• The Korean Journal of Ecology
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• v.12 no.2
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• pp.67-73
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• 1989

The action and growth of soil microorganisms were studied in accordance with the leachates from leaf litter over the time lapse, and soil properties and species compositions in studied area were investigated. The investigations of soil microorganisms were made through dividing into two groupsbacterial and fungal groups. The abundance of soil microorganisms showed high correlation with organic matter(0.98) and total nitrogen(0.97) of soil. The amount of soil microorganisms was found the highest in litter layer and the next were humus and A layer in order. The bacterial growth rate in leachates from leaf letter was increased continuously by two weeks. The fungal growth rate was increased only for one week and after then it was decreased abruptly.

• Applied Biological Chemistry
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• v.9
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• pp.153-159
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• 1968

In this paper the auther investigated the chemical properties, process of humification and type of humic acid in soils which were reclaimed by farming for cultivation in Kangwondo. The results obtained in this studies were summarized as follows: 1. General chemical components of these soil were similar to the ordinary soil but C.E.C. and humus contents were found much more 2. Humic acid and fulvic acid which were extracted with NaOH from soil were greater than those of Na-pyrophosphate(Na-p.) and NaF. Hmus contents and PQ% were increased much more in the upper layer than in the lower layer. 3. Degree of humification of humic acid extracted with NaOH. was very similar to those extracted with Na-pyrophosphate. Humification degree of humic acid extracted with NaF was lower than humic acid which were extracted with NaOH and Na-pyrophosphate. But humification degree of humic acid extracted with NaOH was similar to that with Na-pyrophosphate. Humic acid in B soil and the upper layer was higher than A, C soil and the lower layer of soil, in humification degree. 4. Humic acids extracted with NaOH and Na-pyrophosphate from soil were fractionated by Mg into two parts ${\alpha}$ type and ${\beta}$ type humic acid. Humic acids of ${\alpha}$ and ${\beta}$ type extracted with NaOH were higher than these of Na-pyrophosphate in humification degree. In this soil the humification degree of humic acid was not changed during the period of cultivation. 5. ${\alpha}$, ${\beta}$ type humic acid extracted with NaOH were very similar to the humic acid extracted with Na-pyrophosphate in shapes of absorption curves.

• Journal of Korean Society of Forest Science
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• v.23 no.1
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• pp.29-33
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• 1974

U-Reuk, a laureate musician in the days of King Jin-Heung, Silla Dynasty, built the Eui Rim Reservoir about 1,400 years ago. This was one of the oldest man-made reservoir. The embankment of the reservoir collapsed by the clumsy artificial drainage on August 19, 1972 when the heavy rainfall of 462 mm/day caused a dangerous overflow of the reservoir. The result of the study on the mystic ancient embankment techniques are as follows: 1. Sandy loam derived from the weathering of granite which is the most widely distributed rock type in the area, was used in the embankment. Large size logs (embankment core) of 30-50 cm in diameter were buried lengthwise along the embankment. 2. The six stocks of Pinus densiflora, 3 stocks of Quercus acutissima, 1 stock of Quercus variabilis and 1 stock of Popolus maximowiczii, altogether 11 stocks are identified. Forest types in the nearby area during the days of the reservoir construction seem to be includde a considerable number of Pinus densiflora, Quercus and Populus species. 3. The angle of repose of the earth materials is taken into account during the embankment. On top of the embankment double layers of clay (20-30 cm indepth) were spread and consolidated. Layer of litter of 20-40 cm in deep covered on the clay layer of the embankment completely, and another layer of clay was consolidated over the litter. Finally, a layer of stones of 10-30 cm in diameter and clay (yellow soil layer) toped the embankment. 4. At the lower part of the embankment clay layer was thicker and became thinner as it goes upwards. At every layer, soil was consolidated and burned. When embankment was completed, it was covered evenly with heavy clay, and finally it was topped with general soil. 5. The heavy clay layer on the inner slope of the embankment showed gray phenomena and litter remained raw humus layer. The clay layer functioned as rubber in the water, and raw humus layer prevented water from seepages. Thus, the embankment was solidly built in this way. 6. The ancient embankment techniques used soils conveyed from nearby area taking the angle of repose into account. Once embankment was completed, clay and litter layers were added to have a plasticity and to withstand the water pressure. 7. It is an excellent technique that the reservoir was constructed with least labor for maximum effects while the recent embankment techniques requires a large amount of labor.