• 제목/요약/키워드: Changes in vegetation

검색결과 677건 처리시간 0.028초

복단면 개수로흐름에서 홍수터 식생의 흐름저항을 반영한 1차원 모형 (One-Dimensional Model for Flow Resistance of Floodplain Vegetation in Compound Open-Channel Flow)

  • 박문형
    • 한국수자원학회논문집
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    • 제43권6호
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    • pp.517-524
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    • 2010
  • 본 연구에서는 식생이 포설된 홍수터를 포함하는 복단면 개수로 흐름의 수위를 예측하기 위하여 유효 전단응력기법에 근거한 일차원 모형을 제시하였다. 제안된 모형은 주수로와 홍수터 접합부에서 발생하는 운동량 교환효과를 와점성계수 개념을 이용하여 반영할 수 있다. 주수로와 홍수터의 경계에서 발생하는 경계와점성계수는 3차원 레이놀즈 응력 모형을 이용하여 결정하였다. 경계와점성계수의 영향을 파악하기 위하여 민감도분석을 수행하였다. 경계와점성계수의 변화에 대하여 배수곡선의 변화는 크지 않았으나, 홍수터에서 부담하는 유량은 경계와점성계수에 비례하여 증가하였다. 마지막으로 식생된 홍수터의 식생밀도 및 침수비에 따른 경계와점성계수의 변화를 살펴보았다. 계산된 경계와점성계수는 식생밀도와 침수비에 비례하며, 대략$(2-5){\times}\;10^{-4}$ 정도의 값을 갖는 것으로 나타났다.

Recent Vegetation History and Environmental Changes in Wangdeungjae Moor of Mt. Jiri

  • Kim, Jae-Geun;Lee, Yang-Woo
    • The Korean Journal of Ecology
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    • 제28권3호
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    • pp.121-127
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    • 2005
  • To reveal vegetation history and environmental changes in Mt. Jiri, sediment cores were collected from Wangdeungjae moor of Mt. Jiri. Overall dry matter accumulation rates and sedimentation rates by $^{14}C-dating$ were 0.027 $kg{\cdot}m^{-2}{\cdot}yr^{-1}$ and 0.184 mm/yr since 1250 ($760{\pm}40$ yrs BP, 14 cm in depth). There are three pollen zones; the first zone is below 14 cm depth where Quercus dominated, the second zone is from 14 cm to 6 cm depth where Gramineae increased and Quercus and Salix dominated and the third zone is from 6 cm depth to the top where Pinus and Quercus dominated. Total pollen concentration gradually increased from bottom to the top of sediment core, which implies wet, anaerobic and cool condition during covered period by the core. Calcium and magnesium contents had increased since 14 cm depth, with peaks at 13 and 20 cm depths. This indicates that groundwater had recently become relatively more important than surface water as water source of Wangdeungjae moor Exotic plant or Chenopodiacea pollen was less than 1%. There was little variation in total N and P contents along the length of the core. These results support that Wangdeungjae moor has been little affected by anthropogenic activities. Also, nutrients and heavy metal contents indicate the baseline condition of Wangdeungjae moor.

1950년 이후 한국, 중국, 일본의 식생변화 및 이에 따른 수문순환 변화 분석 (Analysis of change in hydrological cycles of South Korea, China and Japan due to the change of their vegetation since 1950)

  • 송성욱;조은샘;유철상
    • 한국습지학회지
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    • 제19권4호
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    • pp.470-483
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    • 2017
  • 산림면적의 변화와 같은 토지피복 또는 토지 이용의 변화는 물과 에너지 순환의 변화를 유발하여 궁극적으로 하천 유량, 증발산, 토양수분, 기저유량과 같은 수문순환 전반에 큰 영향을 미친다. 본 연구에서는 대규모 지표수문모형과 다양한 토양, 토지이용, 식생, 기상 등의 자료를 이용하여 과거 장기간에 걸쳐 나타난 수문순환의 변화를 모의하였다. 이를 위해 본 연구에서는 동아시아에 해당하는 중국, 일본, 남한에서 나타난 과거 50여 년 간(1955-2010년)의 수문순환 변화를 모의하고 그 결과를 평가하였다. 특히, 본 연구에서는 시기별 동아시아 국가들의 식생분포를 적절히 반영하는 토지피복도를 선별하여 이용하였다. 수문순환 모의 결과, 전 기간에 걸쳐 중국의 유출률 평균이 47.0%로 나타나고, 일본의 경우에는 62.7%, 남한의 경우에는 49.4%로 나타났다. 전체 모의 기간에 따른 토양수분의 평균을 국가별로 살펴보면, 중국이 22.2%, 일본이 35.6%, 남한은 23.9%로 나타났다. 마지막으로 증발산의 경우, 중국의 경우 모의기간 전체에 대한 증발산율 평균은 52.7%, 일본은 37.3%, 남한은 50.4%로 모의되었다. 특히, 중국에서는 모의 시기별(1955-1990년, 1991-2000년, 2001-2010년)로 수문순환의 변화가 뚜렷하게 나타났으며, 일본은 식생 안정화에 따른 안정적인 수문순환 성분을 확인할 수 있었다. 아울러 남한에도 식생 안정화에 따른 수문순환 성분의 안정화가 다소 이루어지고 있는 것을 확인하였다.

백제의 고도(古都) 부여 성흥산성(聖興山城)의 식생구조 및 관리방안 (Vegetation Structures Analysis and Management Plan Proposal for the Sungheung Fortress in Buyeo-the Old city of Baekje)

  • 이선;송호경
    • 한국환경복원기술학회지
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    • 제14권3호
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    • pp.85-100
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    • 2011
  • Vegetation structure of Sungheung fortress in Buyeo was investigated to suggest a desirable management proposal. Forset communities by phytosociological method were classified into Pinus densiflora community, Quercus serrata community and Quercus aliena community. The importance value of Pinus densiflora, Quercus aliena, Quercus serrata, Quercus variabilis, Castanea crenata, Styrax japonica, Quercus acutissima and Prunus sargentii were 34.81, 13.57, 12.63, 6.73, 6.40, 4.70, 4.54 and 3.65. According to breast diameter analysis results, it is expected that the importance value of Pinus densiflora and Quercus spec. will be continuosly increased. It should be prepared that vegetation management plan over the castle wall should be considered before the repair or restoration of castle wall. Vegetation management around castle wall should be carried out according to the mid or long-term plan and it would be needed to consider the gradual changes from planted Pinus rigida to the historical vegetation of Pinus densiflora.

답압이 설악산 아고산대의 식생에 미치는 영향 (Effects of Human Trampling Disturbance on the Vegetation at the Subalpine Zone near the Peak of Mt. Sorak, Korea)

  • 이규송;최오길;김석철
    • The Korean Journal of Ecology
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    • 제25권5호
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    • pp.321-328
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    • 2002
  • 등산객에 의한 많은 간섭을 받아온 설악산 대청봉의 아고산생태계에서 훼손된 식생의 복원에 필요한 기초자료를 제공하기 위하여 인간에 의한 답압에 따른 입지인자와 식생의 변화를 파악하였다. 본 조사지역에서 인간에 의한 간섭은 경사도 10° 미만의 완만한 남사면 지역에서 두드러졌다. 인간의 간섭은 식생의 키. 식피율 및 종다양성을 감소시켰고, 식생의 종조성의 변화를 통하여 식생구조의 변화를 유발하였다. 또한 인간의 간섭은 파괴된 식생으로 인한 낙엽생산이 감소하고, 고산지대 특유의 바람에 의한 낙엽의 이동으로 인하여 낙엽층과 유기물층의 발달이 저해되었다. 이는 토양수분함량을 감소시키고, 토양침식작용이 활발해져 토심이 얕아지고 표토층이 유실되면서 자갈이 지표면에 노출된 입지환경으로 변화시켰다.

地球 溫暖化에 따른 韓半島의 純一次生産力과 潛在自然植生의 變化 推定 (Estimation for Changes of Net Primary Productivity and Potential Natural Vegetation in the Korean Peninsula by the Global Warming)

  • Kim, Jeong-Un;Kil, Bong-Seop
    • The Korean Journal of Ecology
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    • 제19권1호
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    • pp.1-7
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    • 1996
  • The net primary productivity and potential natural vegetation in the Korean peninsula in the 21st century were estimated by the Miami model and thermal climate, respectively, based on 148 meteorological data sets. In the 21st century, the distribution range of the net primary produtivity in the Korean peninsula was estimated as 1,050 g $DM{\cdot}m^{-2}{\cdot}yr^{-1}~2,050g\;DM\cdot m^-2\cdot yr^{-1}.\; These\; values\; increased\; by\; 200g\; DM\cdot m^{-2}\cdot yr^{-1}\;on\;northern\;part\;and\;400g\; DM\cdot m^{-2}\cdot yr^{-1}$ on southern part compared with that of the present century. The potential natural vegetation in the Korean peninsula in the 21st century will change into the followings:coniferous forest on Mt. Paektu area, deciduous broadleaf forest on northern part, and evergreen broadleaf forset on southern part.

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청주 무심천의 교란에 따른 식생분포의 변화 (Changes of Riparian Vegetation in Relation to Disturbance of Musim-Chon Stream, Cheongju)

  • 강상준;곽애경
    • The Korean Journal of Ecology
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    • 제21권5_1호
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    • pp.435-448
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    • 1998
  • The phytosociological investigation was carried out at 32 sites of the riparian vegetation in Musim-Chon stream passed through Choengju-City, Chungcheongbuk-Province by Braun-Blanquet's method from August to October, 1997. The flora of vascular plants in this survey was 202 species. The riparian vegetation was classified into 25 communities as follows. The submerged hydrophytes are Potomogeton malaianus var. latifolius community, Potomogeton crispus community, Myriophyllum verticillatum community-Hydrilla verticillata community and Ceratophyllum demersum community. The floating-leaved hydrophyte is Trapa japonica community. The emerged hydrophytes are Phragmites communis community, Perzicaria thunbergii community, Phragmites japonica community, Oenanthe javanica community, Zizania latifolia community and Persicaria hydropiper community. The herbaceous vegetation of floodplain are Artemisia montana community, Humulus japonicus community, Miscanthus sacchariflorus community, Erigeron anmus community, Impatiens balsamina community, Bidens frondosa community, Setaria viridis community, Ambrosia artemisiifolia var. elatior community and Eragrostis ferruginea community. The woody vegetation of floodplain are Robinia pseudo-acacia community, Stephanandra incisa community and Clematis apiifolia community. The species diversity was low in the upper and down stream, while the diversity was high in the mid stream situated at the center of Choengju-City because of frequent disturbance by citizens. These results suggested that distribution of communities and species diversity was closely related to the disturbance.

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여의도공원 내 조성된 '자연생태의 숲'의 초기 식생 변화 (Early Changes in Vegetation after the Construction of 'the Ecological Forest' in Youido Park)

  • 이상원;김동엽
    • 한국환경복원기술학회지
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    • 제4권1호
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    • pp.41-51
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    • 2001
  • 'The Ecological Forest' in Youido Park was intended to be an artificial forest in urban center, following the form of natural forests in central Korea. This study was to investigate the planting plan and the vegetation change of 'the Ecological Forest' and to compare it with natural forests of similar plant composition. The natural forests had slopes between $12^{\circ}$ and $21^{\circ}$, whereas 'the Ecological Forest' had slopes between $2^{\circ}$ and $6^{\circ}$. It was unlikely that the slope condition was adequate to show 'toposequence succession' at 'the Ecological Forest'. The soil bulk density and soil hardness of 'the Ecological Forest' were higher than those of the natural forests. The soil pH of 'the Ecological Forest' was 7.45, which was greater than that of the natural forests. There were some changes in plant composition and amounts 2 years after the construction : the number of conifers was reduced from 383 to 338 ; the number of deciduous trees was reduced from 4717 to 1158. It was because of the young trees dead in the sub-tree layer. The herbaceous species planted were 14 families, 31 species, which increased to 37 families, 93 species after 2 years. In case of horizontal structure of vegetation, trees and shrubs were distributed evenly in the natural forests, whereas 'the Ecological Forest' showed uneven distribution with higher total density. In case of vertical structure of vegetation, the natural forests had distinctive layers with dominant species distributed in each layers. In 'the Ecological Forest', however, dominant species were only in tree layer. The natural forests had greater average tree height, tree density, however, and basal area than 'the Ecological Forest'. The results showed that there were some differences in the structure between 'the Ecological Forest' and natural forests. The management plan should be applied in order that the natural condition be restored in 'the Ecological Forest' by competition between plant species and natural processes.

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Analysis of Electroencephalogram and Electrocardiogram Changes in Adults in National Healing Forests Environment

  • Hong, Jae-Yoon;Lee, Jeong-Hee
    • 인간식물환경학회지
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    • 제21권6호
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    • pp.575-589
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    • 2018
  • This study analyzed the changes in Electroencephalogram(EEG) and Electrocardiogram(ECG) depending on the healing environment in order to find a way to improve the forest healing program based on the healing environment in response to the demand for qualitative improvement of the program since the program is a charged service. This study selected eight sites running forest healing programs at four national healing forests (i.e., Saneum, Cheongtaesan, Daegwanryeng, and Jangseong) - two routes per national healing forest - considering forest environments. This study chose NUMBER standard sampling plots ($20{\times}20m$) and measured three atmospheric environment items, seven physical environment items, two soil environment items, and eight vegetation environment items including forest sound and anion at each plot to evaluate physiological changes in it. EEG and ECG, which have been widely used in forest healing evaluation, were utilized as criteria. Seventy three subjects were selected with taking the age, drug, caffeine, smoking, and the time of last meal into consideration. As a result, EEG changes were correlated with three atmospheric environment items, six physical environment items, one soil environment item, and two vegetation environment items. ECG changes were significantly correlated with two atmospheric environment items, six physical environment items, two soil environment items, and two vegetation environment items (p<.05). It is expected that 11 environmental factors such as temperature, density, and altitude affecting EEG (e.g., alpha balance and gamma balance) and ECG (e.g., HRV mean) could be used as effective tools in developing more differentiated programs for improving healing effects.

식생수로의 유속분포에 관한 실험적 연구 (An Experimental Study on Velocity Profile in a Vegetated Channel)

  • 권도현;박성식;백경원;송재우
    • 한국수자원학회:학술대회논문집
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    • 한국수자원학회 2004년도 학술발표회
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    • pp.957-960
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    • 2004
  • From a water-environmental point of view, with a change of understanding and concern about vegetation, it changes that vegetation acts as stability of channel and bed, providing habitats and feed for fauna, and means improving those with appreciation of the beautiful but resistant factor to the flow So, it becomes important concern and study subjects that turbulent structure by vegetation, shear stress and transport as well as roughness and average velocity by vegetation. But from a hydraulic point of view, vegetation causes resistance to the flow and can increase the risk of flooding, Therefore, this thesis concern the flow characteristics in vegetated open channels. According to the experimental results, $z_0$ was on an average $0.4h_p$ in a vegetated open channel. So, the elevation corresponding to zero velocity in a vegetated channel was the middle of roughness element. The limit for logarithmically distributed profile over the roughness element was from $z_0$ to $0.80h_{over}$ for a vegetated channel. Among the existing theory, the method of Kouwen et al.(1969), Haber(1982), and El-Hakim and Salama(1992) except Stephan(2001) gave a very good value compared to the measured velocity profile.

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