• 제목/요약/키워드: VEGETATION DENSITY

검색결과 417건 처리시간 0.023초

Soil organic carbon characteristics relating to geomorphology near Vestre Lovénbreen moraine in Svalbard

  • Jung, Ji Young;Lee, Kyoo;Lim, Hyoun Soo;Kim, Hyun-Cheol;Lee, Eun Ju;Lee, Yoo Kyung
    • Journal of Ecology and Environment
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    • 제37권2호
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    • pp.69-79
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    • 2014
  • Soil organic carbon (SOC) in the Arctic is vulnerable to climate change. However, research on SOC stored in the high Arctic regions is currently very limited. Thus, this study was aimed at understanding the distribution and characteristics of SOC with respect to geomorphology and vegetation in Svalbard. In August 2011, soil samples were collected near the Vestre Lov$\acute{e}$nbreen moraine. Sampling sites were chosen according to altitude (High, Mid, and Low) and differences in levels of vegetation establishment. Vegetation coverage, aboveground biomass, and SOC contents were measured, and density-size fractionation of SOC was conducted. The SOC content was the highest in the Mid site ($126.9mg\;g^{-1}$) and the lowest in the High site ($32.1mg\;g^{-1}$), although aboveground biomass and vegetation coverage were not different between these two sites. The low SOC content measured at the High site could be related to a slower soil development following glacial retreat. On the other hand, the Low site contained a high amount of SOC despite having low vegetative cover and a high ratio of sand particles. These incompatible relationships between SOC and vegetation in the Low site might be associated with past site disturbances such as runoff from snow/glacier melting. This study showed that geomorphological features combined with glacier retreat or melting snow/glacier effects could have affected the SOC distribution and vegetation establishment in the high Arctic.

임도비탈면의 복원을 위한 식생기반재 돌망태의 안정성 분석 (Using Gabion Systems with Vegetation Base Materials on Stability Analysis for the Forest Road Cut-slope Rehabilitation Techniques)

  • 박재현;정용호;최형태
    • 한국환경복원기술학회지
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    • 제12권2호
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    • pp.106-113
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    • 2009
  • In this study, stability of the new gabion system with vegetation base materials was analysed. New gabion system with vegetation base materials is a new approach which has been developed to achieve lope stabilization and revegetation of forest road cut-slope by making the best use of advantages of gabion systems with vegetation base materials. Results from stability analysis are as follows. For the soil density, the angle of internal friction and unit weight of the rock fill was assumed to be $1.90g/cm^3$, $30^{\circ}$ and $2.30t/m^3$, respectively, the slope stability analysis showed that the new gabion system couldn't require any poles to fix it up, and could keep stable during both rainy and dry seasons. As the results of checks against overturning and sliding, the retaining wall with. the new gabion system could produce suitable factors of safety for overturning and sliding. Vegetation established on the surface of the new gabion systems indirectly can help to increase slope stability by prevention of surface erosion. Consequently, the new gabion system with vegetation base materials could achieve the desired effect on slope stabilization as much as existing gab ion system could do, and could promote rapid establishment of vegetation on cut-slopes.

폐탄광 경석지 식생 복원을 위한 식물군집 조사·분석 - 강원도 태백시 함태탄광 폐탄광지를 사례로 - (Plant Community Survey and Analysis for Restoration of Vegetation in Coal-mined Spoil Lands - A Case Study of Hamtae Coal-mined Spoil Lands in Taebaek City, Kangwondo -)

  • 김보현;김경훈;김혜주;김두하
    • 한국환경복원기술학회지
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    • 제3권4호
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    • pp.33-42
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    • 2000
  • This study is carried out to investigate plant community structure, actual vegetation map and flora for examining the relationship between naturally introduced vegetation and surrounding vegetation in Hamtae coal-mined spoil lands. According to the analysis of vegetation, surrounding vegetation was divided into five plant community groups : Pinus koraiensis community, Pinus densiflora - Quercus mongolica community, Q. mongolica - Deciduous broadleaved trees community, Betula schmidtii - B. davurica community, Larix leptolepis community. Robinia pseudo-acacia, which had been planted, was dominant species in coal-mined spoil lands. Young trees, which were naturally introduced, such as B. schmidtii, B. davurica etc., partially appeared with the high density($15{\sim}19ea/100m^2$) in coal-mined spoil lands. The flora of this area was listed as 54 taxa; 22 families, 42 genus, 50 species, 3 varieties and 1 forma. Especially Spodiopogon sibiricus, Miscanthus sinensis, Arundinella hirta, Artemisia capillaris, Artemisia iwayomogi and Youngia denticulata appeared with the high frequency. It is estimated that the proper way for harmonious and effective revegetation is to target B. schmidtii - B. davurica communities and to seed B. schmidtii - B. davurica mixing highly frequent herbaceous species.

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생태적 접근방법에 의한 식생복원 및 관리계획 (Natural Vegetation Restoration and Management Plan by Ecological Approach)

  • 이경재;최송현;강현경
    • 한국환경생태학회지
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    • 제8권1호
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    • pp.58-67
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    • 1994
  • Object of this study is to suggest the plan for natural vegetation restoration and management by ecological approach. The concept of biotope planting technique was introduced in order to restore the natural vegetation in the northern part of Mt. Nam in Seoul, and Quercus mongolica forests was surveyed so as to obtain the basic data. This study focused on the vegetational context between northern part of Mt. Nam and develop-reserved site. The results are following ; 1. It is suitable to plant 25~30 trees in $100\m^2$ with trees of DBH 10cm and below at intervals of about 2m in canopy layer. In the case of subtree layer of DBH 2cm, about 30 trees were planted at an Intervals of 1.5~2m around in $100\m^2$. 2. In the last step of nature vegetation restoration, it is desiable that canopy density is $5/100\m^2$ and 녀btree one is 10~20/$100\m^2$. 3. Management plans was proposed to use the native species of Mt. Nam around and to investigate the ecological situation once a year such as species introduce, dead-tree, soil, fauna etc.

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교행식생 영역을 갖는 개수로 흐름에서의 3차원 수치모의 (Three-Dimensional Numerical Simulations of Open-Channel Flows with Alternate Vegetated Zones)

  • 강형식;김규호;임동균
    • 대한토목학회논문집
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    • 제29권3B호
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    • pp.247-257
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    • 2009
  • 본 연구에서는 흐름방향으로 식생 영역이 교차적으로 식재된 교행식생 수로에서의 3차원 수치모의를 수행하였다. 지배방정식에서의 난류 폐합을 위해 ${\kappa}-{\varepsilon}$ 모형을 적용하였으며, 수치모형은 Olsen(2004)이 개발한 3차원 모형을 이용하였다. 먼저, 3차원 수치모형을 이용하여 하상의 일부가 식재된 부분 식생 수로를 수치모의 하고, 계산된 적분유속 및 레이놀즈응력을 기존의 실험 결과와 비교하였다. 그 결과 본 모형이 식생 수로에서의 평균 유속 분포를 매우 잘 예측하는 것으로 나타났다. 그러나 ${\kappa}-{\varepsilon}$ 모형이 등방성 모형이므로 식생과 비식생 영역의 경계면 부근에서 발생되는 운동량 교환 효과를 정확히 예측할 수 없는 것으로 나타났다. 한편, 주흐름방향으로 식생 영역이 교차적으로 존재하는 교행식생 수로를 수치모의 하고, 계산된 유속 분포를 기존의 실험 결과와 비교한 결과, 계산 유속과 실험 결과가 매우 잘 일치하는 것으로 나타났다. 또한 다양한 밀도에 따른 유속 벡터도를 계산한 결과, 식생밀도가 증가함에 따라 식생이 흐름 방향을 변화 시켜 점차 만곡수로와 유사한 형태의 유속 벡터도를 갖는 것으로 나타났으며, 식생 밀도 ${\alpha}$가 9.97%인 경우에는 식생 반대 측벽 영역에서 재순환 흐름이 형성되는 것으로 나타났다. 한편, 식생 밀도에 따른 단면 유속 분포도 및 편수위 변화를 살펴보았다.

수심의 제한을 받는 침수식생 개수로의 평균흐름 예측모형 개발 (Development of Mean Flow Model for Depth-Limited Vegetated Open-Channel Flows)

  • 양원준;최성욱
    • 한국수자원학회논문집
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    • 제43권9호
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    • pp.823-833
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    • 2010
  • 침수식생 개수로 흐름은 식생영역과 상부영역에 서로 다른 흐름구조를 보인다. 즉, 식생영역에서 전단으로 인해 생성되는 난류는 억제되며 비교적 균일한 유속 분포를 보이며 상부영역에서는 일반 개수로 흐름과 유사한 흐름구조를 보인다. 이와 같이 두 상이한흐름구조가 결합된 복잡한 흐름특성으로 인해 침수식생 개수로흐름은 공학적인 관심의 대상이 되어왔다. 본 연구에서는 침수식생 개수로 흐름의 층적분 모형의 비교 분석을 수행하였다. 일반적으로 식생흐름의 층적분 모형은 층의 수에 따라 2층 및 3층모형으로 구분한다. 즉, 전체 수심을 식생영역과 상부영역으로 구분하는 2층모형과 식생영역을 바닥 조도의 영향 유무에 따라 내부 및 외부 식생영역으로 구분하는 3층모형으로 분류된다. 본 연구에서는 2층모형과 3층모형을 비교하였다. 다양한 실험조건에 적용한 결과, 3층모형이 식생영역에서 유속의 변화를 고려할 수 있으나 결과는 레이놀즈응력 분포에 민감하며, 적분된 유속은 2층모형에 의한 예측 결과가 더욱 정확한 것으로 나타났다. 3층모형에서 내부 식생영역의 결과가 전체 흐름구조에 미치는 영향이 무시할 수 있으므로 이 점을 착안하여 식생영역에서 유속 변화가 고려되는 수정 2층모형을 제시하였다. 수정 2층모형에서 가정하는 레이놀즈응력 분포는 상부영역에서는 선형, 식생영역에서는 멱함수 형으로 변화한다. 다양한 조건에 적용한 결과, 수정 2층모형이 대체로 기존의 모형과 비슷한 정도의 예측을 수행하나 식생밀도가 매우 작은 흐름의 경우 예측 결과가 불량한 것으로 나타났다.

하천 복원 후의 홍수위 안정성 검토 (Evaluation of River Flood Stability after River Restoration)

  • 김병찬;이종석
    • 한국콘텐츠학회논문지
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    • 제9권10호
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    • pp.417-426
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    • 2009
  • 자연친화적인 하천복원의 관심이 증폭되면서 하도내 식생은 경관이나 기능적으로 매우 중요한 항목으로 인정받고 있다. 반면에 식생은 통수단면적을 줄어들게 하고, 하천 흐름 저항 증가로 인해 유속이 감소, 이에 따른 수위상승이라는 치수적인 측면에서는 부정적인 역할을 하기도 한다. 본 연구에서는 하천 복원으로 인해 수리학적 요소가 급변한 하천에서 정확한 조도계수 산정 방법에 대하여 연구하였다. HEC-RAS와 연직 2차원 수리해석 방법을 이용하여 하천복원 후의 양재천 중하류 구간의 하천조도계수는 주수로 0.011~~0.159, 식생 설치를 하지 않았을 시의 홍수터 0.031, 식생을 설치했을 경우에는 0.034~0.505의 값을 도출할 수 있었다. 또한 홍수터에 추가로 식생 밀도를 30% 증가시켜 본 결과, 양재천에서의 수위 상승은 식생후 보다 0.13~0.34m로 모의되어, 홍수터의 추가 식생에 의한 수위변동은 미비한 것으로 판단된다.

Above- and below-ground vegetative responses to prescribed fire regimes in a Chesapeake Bay tidal brackish marsh

  • Leonard, Cheryl A.;Ahn, Chang-Woo;Birch, Dixie
    • Journal of Ecology and Environment
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    • 제33권4호
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    • pp.351-361
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    • 2010
  • The primary purposes for using fire are to enhance marsh vegetation to support waterfowl, and to manage invasive plant species. The study was conducted for two consecutive years in 2004 and 2005, investigating the effects of prescribed fire regimes on vegetation biomass in tidal brackish marsh areas of the Blackwater National Wildlife Refuge located on the eastern shore of Maryland, USA, that are under relatively similar environmental conditions. Four different burn regimes (i.e., annual burn, 3-5 year burn, 7-10 year burn, and no burn) were applied in the study. Above- and below-ground vegetation biomass samples as affected by the different burn regimes were harvested in each year for five plant species native to the marsh; Distichlis spicata, Spartina alterniflora, Schoenoplectus americanus, Spartina cynosuroides and Spartina patens. No significant difference was found either in total above-ground biomass or in above-ground biomass by species between burn regimes in 2004. However, more total above-ground biomass was produced in annual burn regime in 2005 than in the other burn regimes. There were no consistent effects of burning on vegetative biomass production by species, but it seemed D. spicata was somewhat benefited by prescribed burning for its biomass production. Moreover, the stem density for D. spicata under annual burn regime was significantly higher than that in the other burn regimes, showing some positive effects of burning on vegetation. The below-ground biomass was significantly greater in 2004 than in 2005, yet with no significant difference between burn regimes in either year. A longer-term monitoring is strongly recommended.

EVALUATION FOR DAMAGED DEGREE OF VEGETATION BY FOREST FIRE USING LIDARAND DIGITALAERIAL PHOTOGRAPH

  • Kwak, Doo-Ahn;Chung, Jin-Won;Lee, Woo-Kyun;Lee, Seung-Ho;Cho, Hyun-Kook;We, Gwang-Jae;Kim, Tae-Min
    • 대한원격탐사학회:학술대회논문집
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    • 대한원격탐사학회 2007년도 Proceedings of ISRS 2007
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    • pp.533-536
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    • 2007
  • The LiDAR data structure has the potential for modeling in three dimensions because the LiDAR data can represent voxels with z value under certain defined conditions. Therefore, it is possible to classify the physical damaged degree of vegetation by forest fire as using the LiDAR data because the physical loss of canopy height and width by forest fire can be relative to an amount of points reached to the ground through the canopy of damaged forest. On the other hand, biological damage of vegetation by forest fire can be explained using the NDVI (Normalized Difference Vegetation Index) which show vegetation vitality. In this study, we graded the damaged degree of vegetation by forest fire in Yangyang-Gun of South Korea using the LiDAR data for physical grading and digital aerial photograph including Red, Green, Blue and Near Infra-Red bands for biological grading. The LiDAR data was classified into 2 classes, of which one was Serious Physical Damaged (SPD) and the other was Light Physical Damaged (LPD) area. The NDVI was also classified into 2 classes which are Serious Biological Damaged (SBD) and Light Biological Damaged (LBD) area respectively. With each 2 classes ofthe LiDAR data and NDVI, the damaged area by forest fire was graded into 4 degrees like damaged class 1,2,3 and 4 grade. As a result of this study, 1 graded area was the broadest and next was the 3 grade. With this result, we could know that the burned area by forest fire in Yangyang-Gun was damaged rather biologically because the NDVI in 1 and 3 grade appeared low value whereas the LiDAR data in 1 and 3 grade included light physical damage like the LPD.

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동아시아의 황사발원지들에 대한 토지피복 비교 연구: 고비사막과 만주 (A Comparative Analysis of land Cover Changes Among Different Source Regions of Dust Emission in East Asia: Gobi Desert and Manchuria)

  • 피경진;한경수;박수재
    • 대한원격탐사학회지
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    • 제25권2호
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    • pp.175-184
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    • 2009
  • 본 연구에서는 변화하고 있는 지표를 파악하기 위하여 기존황사발원지인 고비사막과 새로운 황사발원지로 주목받고 있는 만주에 대한 토지피복 비교 분석을 수행하였다. 이를 위해 1999년과 2007년의 SPOT VEGETATION(VGT) 센서로부터 취득된 Normalized Difference Vegetation Index (NDVI) 10-day 자료를 사용하였다. 효율적으로 식물의 변화를 탐지하기 위해 NDVI패턴을 분석하고, 식생의 밀도에 따라 level로 분류하여 식생상태를 비교하였다. 그 결과 모든 level을 통해 황사발원지들의 동진추세를 확인할 수 있었다. 또한 기존의 황사발원지였던 고비사막과 황토고원은 positive한 변화를 보인 반면 새로운 황사발원지인 내몽골 고원과 만주는 negative한 변화를 보임을 관찰하였다. 특히 만주는 다른 황사발원지들과 다르게 사막이나 나지의 특성을 가지고 있지는 않으나 지속적으로 negative하게 변화함을 SPOT VGT의 1999년에서 2007년까지 9년 동안의 자료를 분석하여 확인하였다.