• Journal of Ecology and Environment
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• 제42권3호
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• pp.128-138
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• 2018

Background: This study investigated the variation of soil organic carbon in four land cover types: natural and mixed forest, cultivated land, Eucalyptus plantation and open bush land. The study was conducted in the Birr watershed of the upper Blue Nile ('Abbay') river basin. Methods: The data was subjected to a two-way of ANOVA analysis using the general linear model (GLM) procedures of SAS. Pairwise comparison method was also used to assess the mean difference of the land uses and depth levels depending on soil properties. Total of 148 soil samples were collected from two depth layers: 0-10 and 10-20 cm. Results: The results showed that overall mean soil organic carbon stock was higher under natural and mixed forest land use compared with other land use types and at all depths ($29.62{\pm}1.95Mg\;C\;ha^{-1}$), which was 36.14, 28.36, and 27.63% more than in cultivated land, open bush land, and Eucalyptus plantation, respectively. This could be due to greater inputs of vegetation and reduced decomposition of organic matter. On the other hand, the lowest soil organic carbon stock under cultivated land could be due to reduced inputs of organic matter and frequent tillage which encouraged oxidation of organic matter. Conclusions: Hence, carbon concentrations and stocks under natural and mixed forest and Eucalyptus plantation were higher than other land use types suggesting that two management strategies for improving soil conditions in the watershed: to maintain and preserve the forest in order to maintain carbon storage in the future and to recover abandoned crop land and degraded lands by establishing tree plantations to avoid overharvesting in natural forests.

• Journal of Forest and Environmental Science
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• 제29권4호
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• pp.249-256
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• 2013

The aim of the study was to reveal the scope and benefits derives from establishing carbon forests in a country like Bangladesh. Carbon forestry is the modernized forestry practice that evolves no cutting of trees or vegetation rather conserves them in the wood. Trees might be the source of carbon sink at large scale by establishing carbon forests. To find out how and in what extent forests of Bangladesh could contribute to global emission reduction, tree species of economic importance were taken into account about their carbon sequestration potential. Data source was a secondary one. Bangladesh has subtropical evergreen and deciduous forest tree species. Here trees can sequester almost 45-55 percent organic carbon in their biomass. On an average, trees in different types of stands can sequester 150-300 tC/ha. Carbon value of these forests might be 7,500-15,000 USD per hactre (assuming 50 USD per equivalent $tCO_2$). Thus, accounting tree carbon credits of total forested lands of Bangladesh, there might be a lump sum value of $1.89{\times}10^{10}-3.79{\times}10^{10}$ USD. If soil carbon is added, this amount would jump. Alternatively, there are two times higher spaces as marginal lands than this for starting carbon forestry. However, carbon forestry concept is still a theoretical conception unless otherwise their challenges are addressed and solved. Despite of this, forests of Bangladesh might be the key showcase for conserving biodiversity in association with carbon capture. Protected areas in Bangladesh are of government wealth, however, degraded and denuded waste and marginal lands might be the best fit for establishing carbon forests.

• Journal of Microbiology
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• 제44권2호
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• pp.177-184
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• 2006

The characteristic biodegradation of monomeric styrene by Phanerochaete chrysosporium KFRI 20742, Trametes versicolor KFRI 20251 and Daldinia concentrica KFRI 40-1 was carried out to examine the resistance, its degradation efficiency and metabolites analysis. The estrogenic reduction effect of styrene by the fungi was also evaluated. The mycelium growth of fungi differentiated depending on the concentration levels of styrene. Additionally P. chrysosporium KFRI 20742 showed superior mycelium growth at less than 200 mg/l, while D. concentrica KFRI 40-1 was more than 200 mg/l. The degradation efficiency reached 99 % during one day of incubation for all the fungi. Both manganese-dependent peroxidase and laccase activities in liquid medium were the highest at the initial stage of incubation, whereas the lowest was after the addition of styrene. However, both activities were gradually recovered after. The major metabolites of styrene by P. chrysosporium KFRI 20742 were 2-phenyl ethanol, benzoic acid, cyclohexadiene-1,4-dione, butanol and succinic acid. From one to seven days of incubating the fungi, the expression of pS2 mRNA widely known as an estrogen response gene was decreased down to the level of baseline after one day. Also, the estrogenic effect of styrene completely disappeared after treatment with supernatant of P. chrysosporium KFRI 20742 from one week of culture down to the levels of vehicle.

• Journal of Microbiology and Biotechnology
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• 제34권9호
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• pp.1867-1875
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• 2024

Identification of the biochemical metabolic pathway for lignin decomposition and the responsible degradative enzymes is needed for the effective biotechnological valorization of lignin to renewable chemical products. In this study, we investigated the decomposition of kraft lignin by the soil bacterium Pseudomonas kribbensis CHA-19, a strain that can utilize kraft lignin and its main degradation metabolite, vanillic acid, as growth substrates. Gel permeation chromatography revealed that CHA-19 decomposed polymeric lignin and degraded dehydrodivanillin (a representative lignin model compound); however, the degradative enzyme(s) and mechanism were not identified. Quantitative polymerase chain reaction with mRNAs from CHA-19 cells induced in the presence of lignin showed that the putative genes coding for two laccase-like multicopper oxidases (LMCOs) and three dye-decolorizing peroxidases (DyPs) were upregulated by 2.0- to 7.9-fold compared with glucose-induced cells, which indicates possible cooperation with multiple enzymes for lignin decomposition. Computational homology analysis of the protein sequences of LMCOs and DyPs also predicted their roles in lignin decomposition. Based on the above data, CHA-19 appears to initiate oxidative lignin decomposition using multifunctional LMCOs and DyPs, producing smaller metabolites such as vanillic acid, which is further degraded via ortho- and meta-ring cleavage pathways. This study not only helps to better understand the role of bacteria in lignin decomposition and thus in terrestrial ecosystems, but also expands the biocatalytic toolbox with new bacterial cells and their degradative enzymes for lignin valorization.

• 환경영향평가
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• 제17권1호
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• pp.25-45
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• 2008

This review was made to discuss the issues of ecological restoration and environmental impact assessment (EIA) related to the preservation of natural environment, the central theme expressed in the National Anthem of Korea. The authors notice that the key word or the central philosophy contained in the verses of the National Anthem of Korea is the preservation of national land and eternal identity for future generations, which is thought to be pursued through the attainment of ecological sustainability. A conceptual model for the sustainable management of natural ecosystems was suggested for the efficient utilization and the preservation of them, whose activities should be promoted by those of conservation and restoration instead of destructive development and negligence, respectively. Here, the preservation of natural environment can be directly pursued through the restoration of degraded ecosystems and landscapes and the utilization of natural environment can be directly pursued through the conservation of natural resources and wise management of natural ecosystems and landscapes. After reviewing the major characteristics and activities of the restoration of degraded ecosystems and landscapes, discussion was further extended to points for the promotion of the EIA activities. To point out some of them, it is needed for the public to better understand the nature of sustainable management of natural environment, for the society to put extensive energy and resources in the restoration of degraded ecosystems and landscapes, and for the government to install higher levels of ministries than that of the Ministry of Environment in dealing with the issues related to the 'preservation' of national land, people, culture and the security of the sustainability for future generations, where EIA and strategic environment assessment (SEA) can directly contribute to the sustainability of the country and future generations.

• 조명전기설비학회논문지
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• 제19권2호
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• pp.138-144
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• 2005

본 논문에서는 산불이 송전용 폴리머애자에 미치는 영향을 연구하기 위해 인공화염 시험장치를 제작하여 화염의 가열 시간에 따른 폴리머애자의 갓(shed) 변화와 자기애자의 disc 변화를 관찰하고, 전기적$\cdot$기계적 실험을 통하여 특성변화를 확인하였다. 실험결과 다음과 같은 결론을 얻을 수 있었다. 첫째, 화염의 가열시간이 5분정도 경과하였을 때, 자기애자의 전기적 특성은 $80(\%)$ 정도 저하된 반면에 폴리머애자의 경우 갓 유실이 있었지만 전기적 특성의 변화는 $10(\%)$ 정도였다. 폴리머애자를 20분 가열하였을 때는 대부분의 갓이 유실되었지만 전기적 특성치는 $20(\%)$ 정도 감소하였다. 둘째, 폴리머애자와 자기애자 모두 전기적 특성치의 감소는 있었지만 기계적 특성치는 양호하게 나타났다.

• 한국환경생태학회지
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• 제14권1호
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• pp.38-45
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• 2000

강원도 고성군 죽왕면과 토성면 일대의 소나무군락을 대상으로 1996년 4월에 발생한 산화에 따른 산림환경변화가 토양의 이화학성에 미치는 영향을 구명하기 위하여 비산화지역(NF) 산화후 비벌채지역(FNC), 산화후 벌채지역(FC) 및 산화후 조림지역(FCP)으로 분류하여 토양의 특성을 분석하였다. 전조사지역의 토성은 사질식양토이었고, 토양의 입경조성을 비교하면 비산화지역은 표토의 모래함량이 심토보다 낮았고, 점토함량은 높았지만 산화지역은 모두 표토의 모래함량이 점토에 비해 높았다. 토양공극 분포 중 전공극량은 지역별로 큰 차이가 없었으나, 조공극량과 투수성은 비산화지역 ＞ 산화후 비벌채지역 ＞ 산화후 조림지역 ＞ 산화후 벌채지역 순이었고, 세공극량과 가비중은 반대의 경향을 나타내었다. 이는 산화에 따른 산림환경변화로 지피식생이 제거되어 토양침식이 가속화되면서 토양 내 수분함유능력의 지표인 토양공극과 투수성에 큰 영향을 주면서 토양물리성을 악화시키고 있는 것으로 판단된다. 토양 pH는 비산화지역과 산화후 비벌채지역이 산화후 벌채지역과 조림지역보다 표토 및 심토 모두 높게 나타났다. 유기물함량 및 전질소함량 변화는 표토와 심토 모두 비산화지역＞ 산화후 비벌채지역＞ 산화후 조림지역＞ 산화후 벌채지역 순이었다. 양이온치환용량 및 치환성 양이온($K^{+}$ , $Na^{+}$ /, $Ca^{2+}$, $Mg^{2+}$)함량 변화는 모두 표토가 심토보다 높았으며, 지역별로는 비산화지역＞ 산화후 비벌채지역＞ 산화후 조림지역＞ 산화후 벌채지역 순으로, 이는 산화후 표토층의 침식으로 지력이 악화된 결과로 사료된다.

• 한국산림과학회지
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• 제95권1호
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• pp.60-72
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• 2006

본 논문은 해방 이후 가정용 연료재의 대체와 산림녹화의 연관성을 평가하였다. 해방 이후 1960년대 초반까지 총 입목축적의 약 17%에 해당하는 연간 1천만 $m^3$ 내외의 목재를 가정용 연료재로 소비한 까닭에 우리나라는 심각한 산림황폐화에 직면하게 되었다. 1955년 가정용 연료재의 소비량이 그대로 유지될 경우 10년 내에 전국의 산림이 민둥산이 될 정도로 심각한 상황이었다. 이런 문제를 해결하기 위해 상공부는 국내의 유일한 부존자원인 무연탄을 이용하여 가정용 연료재를 대체하는 에너지정책을 추진하였다. 농림부는 대도시 내 임산연료의 반입을 금지하고 가정용 연료재를 연탄으로 대체하여 나갔다. 이런 정책은 점차 성공을 거두어 1970년에 이미 취사용 연료로 임산연료를 사용하는 도시 가구는 5.2%에 불과하였다. 또한 1970년대 이후 가정용 연료재의 실질적 소비자인 농촌인구가 도시로 급격히 이주함에 따라 연료재 소비량도 자연스럽게 감소하였다. 농촌지역의 취사용 연료재는 1985년 이후 가스로, 난방용 연료재는 1980년 이후 연탄으로 급격히 대체되었다. 결국 가정용 연료재의 대체라는 근본적인 변화가 토대가 되어 지난 1세기 이상 진행된 산림황폐화는 마침내 마침표를 찍게 되었다.

• 한국산림과학회지
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• 제112권4호
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• pp.554-560
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• 2023

불법 목재 유통을 막기 위해 DNA를 활용한 수종 및 원산지 식별이 이루어지고 있지만, 목재의 물리·화학적 특성 때문에 양질의 DNA를 얻기 어렵다. 본 연구에서는 목재 DNA 추출 수율과 polymerase chain reaction (PCR) 성공률에 목재 조직의 나이가 영향을 미치는지 알아보기 위하여, 국내 주요 수종인 소나무 원목에서 DNA를 추출하여, 목재의 나이테 생성 시기와 추출 DNA 농도(ng/μl) 및 순도(A260/A280) 그리고 PCR 성공률(%)의 관계를 확인하였다. 분석 결과, 나이테가 형성층으로부터 멀어질수록, 즉 오래 전에 생성된 목재일수록, 추출한 DNA의 농도와 순도는 유의하게 감소하였다. 증폭 길이가 짧은 trnM-trnV(285 bp) 영역과 rpoC1(298 bp) 영역의 경우 PCR 증폭 성공률이 100 %였으나, rbcL(1.3 kb) 영역의 경우 66.67 %였고 30년보다 오래된 조직에서는 모두 증폭에 실패하였다. 시간이 지남에 따라 목재 세포의 사멸과 함께 양질의 DNA가 파괴되어 DNA 농도, 순도, PCR 성공률이 감소한 것으로 판단된다. 본 연구 결과는 향후 목재를 활용한 수종 동정 등에 유용하게 활용될 것으로 기대된다.

• 펄프종이기술
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• 제47권4호
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• pp.151-159
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• 2015

Paper records were generally degraded by some factors from atmospheric environments, like temperature, relative humidity or air pollutants. In this study, the degradation behavior of paper records by single or mixed gases of $NO_2$, $SO_2$, HCHO and TVOC was evaluated. The mechanical, optical and chemical properties of 4 kinds of paper (acid and neutral-based printing paper, traditional Hanji, and filter paper) were directly and indirectly affected by gaseous harmful materials. The brightness and $L^*$ value in all papers were slightly increased by accelerated aging under gaseous HCHO and TVOCs, but highly decreased by conditions under gases $NO_2$ and $SO_2$. The optical properties of paper records were most vulnerable in acid-based paper and high stable in filter paper and traditional Hanji by air pollutant degradation. The aging treatments under mixed gas pollutants including $NO_2$ resulted in decrease of physical, mechanical and optical properties of paper, so it was supposed that the concentration of $NO_2$ gas would be strictly controlled for optimum indoor air quality management in domestic storage centers for paper records.