Assisted natural regeneration of selected tree species through silviculture interventions as a tool for restoring degraded natural forests in northwestern Ethiopia

Melkamu Kassaye,Amsalu Nigatu,Bahiru Gedamu,Yonas Derebe,Mulugeta Tamer,Fentahun Ayne,Etsegenet Emiru,Beyene Belay 한국산림과학회 2023 Forest Science And Technology Vol.19 No.3

Natural forest ecosystem assets and services are increasingly deteriorating due to forest deg- radation and deforestation in Northern parts of Ethiopia. Enhancing the natural regeneration status of native tree species through different silviculture practices is highly Forest regener- ation method recommended. Thus, this study aims to investigate the role of different silvi- cultural interventions in enhancing the regeneration condition of selected ecological and economical important tree species. Three natural forests stands from different agro-ecologies were chosen and three silvicultural treatments including Fencing, Fence þ hoeing, Fence þ gap creation, and control (without any intervention) with 400 m2 plot areas estab- lished with three replications and randomized complete block design (RCBD) with a total of 36 plots. In each plot, seedling, and saplings under different mod of regeneration were recorded while height and diameter at breast height were measured and analyzed using descriptive and inferential statistics using R version 4.1. There was a significant difference (p < .05) in seedling density and regeneration status among forest stands, methods of regen- eration, silvicultural methods, and season of regeneration. The Camboo forest stand recorded the highest regeneration (971 seedlings ha1); seedlings regenerated from seed recorded the highest regeneration (368 seedlings ha1), fencing and gap creation silvicul- tural intervention recorded the highest seedlings (961 seedlings ha1), the highest regener- ation density was recorded at mid-rainy season (570 seedlings ha1); and Prunus africana and Albizia gummifera have the best regeneration capacity (245 seedlings ha1) in the study forest stand. The regeneration status of trees under fencing and gap creation plots changed from J-shape to an inverted J-shape before and after silviculture intervention, respectively. The regeneration and population structure of many studied tree species showed particularly good condition in fenced plots than control plots which shows future management inter- ventions for the restoration of degraded natural forest ecosystems in Ethiopia’s tropical for- est ecosystems. Some native tree species, such as Hagenia abyssinica, Apodytes dimidata, and Ekebrgia capensis, have a weak response to silvicultural treatments that require advanced regeneration techniques such as clonal nurseries and invitro propagation.

내설악 전나무림 천연갱신과 임분특성 -전나무 자연림에서 천연갱신에 대한 개념적 고찰을 중심으로-

윤영일 ( Young Il Youn ) 한국환경생물학회 2009 환경생물 : 환경생물학회지 Vol.27 No.2

전나무의 천연갱신 형태를 임분의 특성과 연관하여 내설악 길골 총 30지역에서 조사하였다. 임학적 의미의 천연갱신은 주로 예전에 인공적 교란이 있었던 곳에서 나타나며 자연림의 특성이 강할수록 오히려 의미를 상실한다. 이것은 인공적 교란이 천연갱신에 더 나은 환경조건을 제공하기 때문으로 보인다. 이와는 달리 자연림에서 갱신단계는 인공림처럼 명확할 수 없고 잠시 나타났다 사라지는 상태이며 세대교체는 임분구조 변화의 일부라는 표현이 적합하다. 특히 patch dynamic이 임분구조를 결정하고 주 구성수종이 음수인 전나무 자연림에서는 인공림에서 사용되는 천연갱신 개념은 원천적으로 의미를 상실할 것으로 보인다. We surveyed the total 30 sites in Gilgol, Nae Sorak for the patterns of the natural regeneration of the korean fir in connection with the characteristic of the stand. The natural regeneration in a forestrical meaning is not found in natural forest but mainly in the anthropogenically already disturbed area. It may be inferred from this fact that the anthropogenic disturbance can give more better condition for a natural regeneration. The regeneration phase in the natural forest is not so distinctive as the artificial forest, and shows itself transiently. And it may be also said that a shift in generation is only a part of the change of the stand phase. The concept of the natural regeneration will lose its meaning, in so far as the patch dynamic determines the phase of the stand, and the main tree species are shade-tolerant abies.

재생횟수 증가에 따른 활성탄의 세공구조 변화가 천연유기물질 흡착에 미치는 영향: 세공크기와 천연유기물질 분자량

손희종(Heejong Son),최상기(Sangki Choi),안병렬(Byungryul An),이혜진(Hyejin Lee),염훈식(Hoon-Sik Yoom) 대한환경공학회 2021 대한환경공학회지 Vol.43 No.7

목적: 입상활성탄의 재생횟수 증가가 천연유기물질(natural organic matter, NOM) 흡착능에 미치는 영향을 평가하여 한계 재생횟수 선정 및 재생탄의 효율적인 사용 방안을 모색하고자 하였다. 방법: 신탄(virgin)과 낙동강 하류의 정수장에서 2년 사용 후 열재생된 1차 재생탄(1st-Re), 2차 재생탄(2nd-Re), 3차 재생탄(3rd-Re) 및 5차 재생탄(5th-Re)에 대한 물리・화학적 특성을 평가하였다. 신탄과 1차∼5차 재생탄들의 NOM 흡착능을 평가하기 위하여 실험실 규모의 흡착 컬럼을 이용한 연속 흡착실험을 수행하였다. 유입수와 각각의 컬럼처리수 중의 NOM 농도를 LC-OCD로 분석하여 각 NOM 분획(humic substances (HS), building blocks (BB), low molecular weights organics (LMWs))들의 흡착능을 평가하였다. 결과 및 토의: 열재생에 의한 활성탄 세공 구조의 변화에 기인하여 직경 2 nm 이하의 미세세공 용적은 감소한 반면, 2 nm 이상의 중간세공 용적이 증가하였다. 신탄에서 2 nm 이하의 미세세공 구성비율은 60% 정도였으나 재생횟수가 증가할수록 점진적으로 감소하여 5차 재생탄의 2 nm 이하의 미세세공 구성비율은 23%까지 감소하였다. 반면, 2 nm 이상의 중간세공 구성비율은 신탄의 40%에서 5차 재생탄의 77%까지 재생횟수에 비례하여 증가하였다. 신탄에 비하여 재생탄들에서 DOC 흡착능은 높았으며, 재생횟수가 증가할수록 DOC 흡착능이 증진되었다. 신탄과 재생탄들에 대한 NOM 분획별 흡착능 평가결과에서 HS와 같은 고분자 NOM의 흡착능은 재생횟수가 증가할수록 1.5배∼1.7배 정도 증진되었으며, 저분자 물질인 BB와 LMWs는 재생횟수가 증가할수록 신탄 기준 78% 및 48%까지 흡착능이 감소하였다. NOM 분획들에 대한 흡착능(qe) 회복율을 신탄 기준 70%로 설정하여 한계 재생횟수를 평가한 결과, 3차 이상의 재생탄들에서는 저분자 NOM에 대한 흡착능이 크게 감소하여 신탄 기준 70%의 성능을 유지하는 재생횟수는 2차까지로 평가되었다. 재생횟수를 3차 이상으로 수행하면서 저분자 NOM (LMWs)에 대한 안정적인 흡착능을 확보하는 방안은 신탄과 3차 이상의 재생탄을 혼합하여 사용하는 방식이 타당할 것으로 판단되며, 신탄에서 유발될 수 있는 고분자 NOM (HS)에 대한 낮은 흡착능도 보완이 가능한 것으로 평가되었다. 결론: 열재생에 의한 활성탄 세공 구조의 변화에 기인하여 신탄에 비해 재생탄들에서 DOC 흡착능 높았으며, 재생횟수가 증가할수록 DOC 흡착능이 증진되었으며, 재생에 의해 중간세공의 용적이 증가하여 고분자 NOM (HS)의 흡착능이 월등히 증진되는 것으로 나타났다. 반면, 재생에 의해 미세세공은 감소하여 재생횟수 3회 이상에서는 저분자 NOM (LMWs)에 대한 흡착능이 신탄 대비 70% 이하로 감소하여 한계 재생횟수는 2차까지로 평가되었다. 3차 이상의 재생탄들과 신탄을 혼합하여 사용할 경우, 저분자 NOM (LMWs)에 대한 안정적인 흡착능을 확보하면서 신탄에서 유발될 수 있는 고분자 NOM (HS)에 대한 낮은 흡착능도 보완이 가능한 것으로 평가되었다. Objectives : The purpose of this study was to evaluate the effect of increasing the number of regeneration of granular activated carbon (GAC) on the adsorption capacity of natural organic matter (NOM), and to suggest the technical process options associated the limit number of regeneration and the efficient use of regenerated GAC. Methods : The physicochemical properties of virgin and thermally regenerated GAC were analyzed. To evaluate the NOM adsorption capacity of virgin- and regenerated-GAC, five laboratory-scale columns packed with virgin- and regenerated-GAC were used for treating effluent from pilot-scale drinking water treatment facility. The NOM concentration in the influent and the effluent treated by each column was analyzed by LC-OCD (liquid chromatography-organic carbon detector) to evaluate the adsorption capacity of each NOM fractions (humic substances (HS), building blocks (BB), low molecular weight organics (LMWs)). Results and Discussion : Due to the change in the pore structure of GAC by thermal regeneration, the volume of micropores (< 2 nm) decreased, while the volume of mesopores (> 2 nm) increased. The volume ratio of micropore in virgin-GAC was about 60%, but it gradually decreased as the number of regenerations increased, resulting that the volume ratio of micropore in the 5th-regenerated (5th-Re) GAC decreased to 23%. On the other hand, the volume ratio of mesopore increased in proportion to the number of regenerations from 40% of the virgin GAC to 77% of the 5th-Re-GAC. The DOC adsorption capacities of the regenerated GACs were higher than that of virgin GAC, and the DOC adsorption capacity increased as the number of regenerations increased. As a result of comparing the adsorption capacity of virgin- and regenerated-GAC by NOM fractions, the adsorption capacity of high molecular weight NOM, such as HS, increased by 1.5 to 1.7 times as the number of regenerations increased. In contrast, the adsorption capacity of low molecular weight NOM, such as BB and LMWs, decreased by 78% and 48% as the number of regeneration increased. The limit number of regeneration was evaluated based on that the adsorption capacity (qe) of each NOM fractions keep over than 70% relative to its virgin GAC. As a result, the adsorption capacity for low molecular weight NOM was greatly reduced in GAC regenerated over than 3rd time, so that the 2nd-Re-GAC was valid to keep 70% removal of whole NOM fractions. Low adsorption of low molecular weight NOM (BB and LMWs) by 3rd-Re-GAC could be complemented by using together with virgin-GAC, and low adsorption of high molecular NOMs (HS) could be compensated as well. Conclusions : Due to the change in the pore structure of GAC by thermal regeneration, the DOC adsorption capacity was higher in regenerated GAC than its virgin-GAC, and the adsorption capacity of DOC and high molecular weight NOM (HS) was enhanced as the number of regenerations increased. On the other hand, the pore volume of micropore was reduced by regenerations, and in more than 3rd times regenerations, the adsorption capacity of low molecular weight NOMs (BB and LMWs) was reduced by less than 70% compared to its virgin GAC, so that 2nd-Re-GAC was suggested for suitable GAC. When using a mixture of virgin- and 3rd-Re-GAC, low adsorption of low molecular weight NOM (BB and LMWs) by 3rd-Re-GAC could be complemented by using together with virgin-GAC, and low adsorption of high molecular NOMs (HS) could be compensated as well.

Structural and Functional Aspects of Sal (Shorea robusta Gaertn. f.) Forests in Kanha Tiger Reserve (KTR)

O.P.Chaubey,Archana Sharma 보안공학연구지원센터 2014 International Journal of Bio-Science and Bio-Techn Vol.6 No.6

Shorea robusta is threatened these days due to sal borer attack, sal mortality, poor regeneration potential, edapho-climatic changes and various biotic interferences. No systematic attempts were made in India, to understand dynamism of its natural regeneration and to suggest management inputs to encourage its regeneration. The present study deals with the natural regeneration with particular reference to crop composition and community structure in Kanha Tiger Reserve in India. The results indicated that the average number of regeneration of sal seedlings per hectare worked out to be 1557 in core zone, 3446 in buffer zone and 7137 in in phen wild life sanctuary which are quite adequate. The distribution pattern of individuals of Shorea robusta trees in different girth classes was also seemed to be uninterrupted in most of the stands studied. This trend of uninterrupted distribution of Shorea robusta in different growth phases with plenty of established regeneration is the healthy sign of establishment and growth of Shorea robusta crop in the past in this area.

천연하종갱신 소나무 임분의 밀도조절 작업 생산성 및 비용 분석

백기광,이은재,정상훈 강원대학교 농업생명과학연구원 2022 강원 농업생명환경연구 Vol.34 No.3

Natural forest regeneration effectively protects forest ecosystems and is a low-cost option compared to artificial regeneration. However, this technology requires increased financial resources for tree tending and blank-filling. A better understanding of the productivity and costs for the tending of young trees in a natural regeneration stand is therefore required, particularly in South Korea. This study aims to evaluate the productivity and cost of young tree tending in the naturally regenerated young Pinus densiflora forests. The tending used to control the density level of pine forests (2,000 trees/ha and 3,000 trees/ha) in the young forest stage was divided into three treatments-row operation, regular pattern operation, and irregular pattern operation. The results demonstrated that the productivity in the operational density level of 3,000 trees/ha was statistically higher than the density level operation of 2,000 trees/ha, barring the irregular pattern operation. The amount of work required for each treatment type was also determined to be significantly different (p < 0.01). In addition, the unit operating cost of the density level of 2,000 trees/ha was considerably higher. The results of this study are expected to be used as basic data required to improve the productivity of the tending of young trees in naturally regenerated young pine tree forests.

소나무 천연갱신지의 목재수확 유형별 종자 유입 특성

정준모,이상태,김현섭,정상훈 한국산림과학회 2023 한국산림과학회지 Vol.112 No.3

This study was conducted to identify seed inflow characteristics according to harvest typeand to provide basic data for developing a regeneration technology for secondary growth forests in Korean red pine (Pinus densiflora) succession forest formation by natural regeneration. Experimental sites were established by applying seed tree (single and group) and clear-cutting methods (10- 20- 30-m strip and 20- 30- 40-m patch). The seed inflow characteristics of the natural regeneration site were analyzed for 6 years from 2014. Most seeds were flowed to the regeneration stand from October to November. In years with good seed fructification, more than 80% were flowed in October. The average annual seed inflow by harvest type was highest in the seed tree area (296,000 seeds/ha/yr), followed by the 20-m patch clear-cutting area (291,000 seeds/ha/yr) and 10-m strip clear-cutting area (281,000 seeds/ha/yr). The distribution uniformity of seed inflow according to treatment was analyzed in the order of the 20-m strip clear-cutting area (52.2), 20-m patch clear-cutting area (52.9), and 10-m strip clear-cutting area (56.1). As a result, the 10-m strip and 20-m patch clear-cutting areas with relatively small harvest areas showed high seed inflow and distribution uniformity.

나다니엘 호손의 인간관과 자연관

백낙승 ( Nakseung Baek ) 미국소설학회(구 한국호손학회) 2015 미국소설 Vol.22 No.3

This study aims to define Nathaniel Hawthorne`s view of Man and Nature in his literary works. Hawthorne having Puritan ancestors is evidently the heir of the Puritan tradition, but he has very critical consciousness against their dogmatic behavior patterns doing much damage to human nature. Like his Puritan ancestors, he has the Calvinistic belief that the Original Sin, committed by Adam and Eve, has resulted in everyone`s innate sinfulness. However, he seeks to establish this view as the basis for a compassionate view of the plights caused by human shared imperfections. In that sense, it may be safely assumed that he is the unwilling heir of the Puritan tradition. Hawthorne`s subject of criticism can be interpreted as all the human negative qualities violating the sanctity of human heart and denying the common heart of humanity rather than the Puritans or the transcendental extremists themselves. It must be noticed that Hawthorne employs the natural objects as symbols to effectively convey his central ideas. His literary strategy lies in evoking poetical associations in New England landscape. As stated in “The Custom-House” of The Scarlet Letter, the writer who is very sensitive to the spirituality of place intends to grasp human mental state projected into the natural landscape. In his fiction, it is interesting that most natural objects symbolically reflect human psyche. In The Scarlet Letter, the prison stands for sin and the cemetery for death, which is closely related to the Puritan dogmatism. On the contrary, the rosebush and the forest represents natural beauty and wildness, which parallels Hester Prynne`s beauty and her mental state unrestrained by Puritan law. Such instances can also be found in his other novels and short stories. Hawthorne`s themes center upon the predicament of individuals alienated from society, the fellowship essential to human survival, and the exploration of the possibility of achieving a regenerated community. He manages to adopt various natural objects as symbols of human psyche, to aesthetically present such themes.

옥수수(Zea Mays L.) 불검화 추출물과 후박(Magnoliae cortex) 추출물의 혼합물이 백서의 두개골 재생에 미치는 영향

김태일,류인철,정종평,이용무,구영,Kim, Tae-Il,Rhyu, In-Cheol,Chung, Chong-Pyoung,Lee, Yong-Moo,Ku, Young 대한치주과학회 2002 Journal of Periodontal & Implant Science Vol.32 No.2

I. Purpose of Study Zea Mays L. has been known to be effective for improving periodontal health and Magnoliae cortex to have effective antibacterial and antimicrobial activity against periodontal pathogens. The purpose of this study was to examine the biologic effects of Zea Mays L. and Magnoliae cortex extract mixtures on healing of rat calvarial bone defects. II. Materials & Methods 8mm circular defects were prepared on rat calvaria during surgical procedures of 180 Sprague-Dawley rats. The ethanolic extracts of Magnoliae cortex and Zea Mays L. and these two natural extract 1:1 and 2:1 (Magnoliae: Zea Mays L.) ratio mixtures were oral administrated by oral zondes once a day at two different dose of 94.5mg/kg, 189mg/kg body weight. There are nine groups of rats in this study: control group (no sample loading), Magnoliae cortex extract loading groups (I,II)(94.5mg/kg,189mg/kg respectively), Zea Mays L. extract loading groups (I,II), M:Z(1:1) loading groups (I,II), M:Z(2:1) loading groups(I,II). Rats were sacrificed at 4 weeks and 6 weeks after surgery. New bone formations around calvarial defects were radiographically and histologically measured by computerassisted histomorphometry. Each data was statistically analyzed by One-way ANOVA test. III. Results There were statistical significances between negative control group and the other test groups on radiographical and histological quantitative assessments. Among test groups, mixture groups showed statistical significances, especially, M:Z (2:1) groups (I and II) were highly significant.(p<0.05) These results implicated that the mixture of Magnoliae and Zea Mays L. (2:1 mixing ratio) with 94.5mg/kg concentration might be highly effective on the wound healing of bony defected site and have potential possibilities as a useful drug to promote bone tissue regeneration.

Pd/SiO2 as an active and durable CH4 oxidation catalyst for vehicle applications

Dong Gun Oh,이재경,김은석,장은정,김지만,곽자훈 한국공업화학회 2021 Journal of Industrial and Engineering Chemistry Vol.99 No.-

The removal of CH4 is critical to address environmental concerns for developing natural gas vehicles(NGVs), because CH4 has a 20-fold-greater contribution to the greenhouse effect than CO2. Aluminasupported Pd catalysts are widely used for CH4 oxidation due to their superior catalytic activity anddurability compared to other CH4 oxidation catalysts. However, the continuous deactivation of Pd-basedcatalysts during vehicle applications needs further development of active and durable catalysts. Here, wereport that Pd/SiO2 can be active and durable catalysts for CH4 oxidation in practically relevant conditionvia a simple reductive regeneration. CH4 oxidation light-off curves of freshly prepared Pd/SiO2 (air, 550C) present higher activity than those of Pd/Al2O3, but severe deactivation was observed afterhydrothermal aging (HTA, air with 10% H2O) at 850 C. However, X-ray diffraction (XRD), scanningtransmission electron microscopy (STEM) and volumetric CO adsorption suggest that Pd/SiO2 has similarparticle sizes as Pd/Al2O3 even after HTA, indicating that Pd/PdO particle sintering is not the origin of thedeactivation of Pd/SiO2. Diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) shows thatthe CO was not adsorbed on Pd/SiO2 after HTA, whereas it was adsorbed on Pd/Al2O3 after HTA. Theseresults demonstrate that the deactivation of Pd/SiO2 originates mainly from the blockage of the Pd/PdOsurface by the SiO2 overlayer formed during HTA. The Pd/PdO surfaces are re-exposed by a simple H2treatment at 500 C, resulting in CO adsorption on the Pd/PdO surface and regeneration for CH4 oxidationactivity, which suggests that the Pd/PdO surface was re-exposed by a reduction treatment. This work alsodemonstrates that SiO2-supported Pd catalysts can be a good candidate for active and durable CH4oxidation catalysts by using the proper regeneration protocols

김기림 시의 표상성

이근화 한국문학이론과비평학회 2008 한국문학이론과 비평 Vol.38 No.-

Kim Ki-rim assimilates the Western civilization in his poetry and literature theory. He is a little more aggressive as a poet than any other writers. Modern sensibility and universal cosmopolitanism is the most important factor for him. He makes a question what is a citizen of the modern life in the realities of our life. The using of a word of foreign origin and introducing a new style arouse criticism. The strong criticism about artificial language is based on national consciousness and racial spirit, because that nationalism identity is made up of the principle of self-determination of peoples, showing favoritism toward born and bred language. But the language of national literature, absolutely doesn't put together heterogeneous language and any other cultural factor. A culture shock does not answer in the negative. Under the stress of extraneous things, a plentiful literature language was formed. Kim Ki-rim gives a shape to poetic diction in his poetry. He lays emphasis on objective point of view and a determined goal in his writing. Therefor his idealism paradoxical as it may seem, may be too realizable possibility. The presentationism of his poetry reveals symbolic words. A 'rose' and 'tulip' is an affirmative concept that he gives an positive answer about a civilization and enlightenment. The 'sun' and the 'ocean' stands for his experiments of movement for cultural regeneration. A light and shade of nature of the world answered the purpose of his efforts. This paper aims to pay attention to an aspect of representative language and the coming of a new world in the poetry of Kim ki-rim. His literary merit is being the center of ideas and a enlargement of knowledge is meaningful for him. The symbolic words of Kim Ki-rim's poetry show a complications of between Joseon of the past and the colonial particularity. He creates a new poetic diction that was setting up scaffolding of literature language of the 1930's. The poetic diction reveals a trait of the point at issue, but he has come up to the new question, being confronted with a contradiction of the time.