• Journal of the Korean Society of Environmental Restoration Technology
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• v.16 no.6
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• pp.1-15
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• 2013

The present Namgang Dam had been completed in 2000, Salix subfragilis communities began to form in 2003 and their distribution area have been rapidly extended into nine times in 2010. In order to deduce correlation between water level and distribution of Salix subfragilis communities under this background in Namgang-dam reservoir, distribution characteristics and widening direction of Salix subfragilis communities have been analyzed by aerial photographs and water levels has been reviewed, also heights and ages of Salix subfragilis have been surveyed in field. The water levels of Namgang-dam related germination of Salix subfragilis have been analyzed in May and June from 2000 to 2010, mean water level, minimum water level and maximum water level were 37.87m, 36.99m and 38.82m, respectively. The oldest ages were 9-13 years, average diameters of breast height, average heights, average numbers and average crown area were respectively 3.9-8.8cm, 3.8-7.5m, $0.53/m^2$ and $0.98m^2/m^2$ in sites. Therefore, this results showed that the first recruitment of Salix subfragilis was in May 2002 when water levels have been maintained as 38.76-41.31m and the widening of Salix subfragilis communities was in May 2004 and 2005 when mean minimum water levels have been maintained as 38.76-41.31m. Salix subfragilis communities formed climax forest in Namgang-dam shore, this phenomena were different from the succession processes of Salix in rivers appeared landforming by deposition of sediment.

• Journal of Ecology and Environment
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• v.30 no.4
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• pp.341-346
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• 2007

Nest density was determined and tree and soil characteristics around Nycticorax nycticorax breeding sites and non-breeding sites on Bamsum Island in Seoul were analyzed from May 2005 to October 2006 to identify breeding site preferences of N. nycticorax and the effects of N. nycticorax nesting density on nesting tree structure and soil characteristics. N. nycticorax preferred trees of low height ($3.5{\sim}6$ m) and small diameter at breast height in high density Salix communities. Excrement of heron juveniles was dropped on the soil under the nests. The soil nutrient content under nests (P: 126.0 mg/kg, N: 202.8 mg/kg, EC: 549 ${\mu}S/cm$, pH 4.7) was much higher than that of control soils from Bamsum Island not enriched by heron excrement (P: 41.5 mg/kg, N: 42.0 mg/kg, EC: 342 ${\mu}S/cm$, pH 5.1). Formation of Salix communities on the shores of Bamsum Island is ongoing, and their structure has been directly influenced by annual flooding. After flooding, the nutrient content differences between heron-affected soils and control soils were not significant. This might be the reason that Salix communities on Bamsum were not affected by nesting herons as in other terrestrial communities where herons nest. This result indicates that flooding plays an important role in sustaining Salix communities on Bamsum Island where herons nest. The results of this study may increase understanding of N. nycticorax breeding behavior which may be useful for conservation planning.

• Journal of Environmental Science International
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• v.18 no.2
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• pp.153-167
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• 2009

Riparian vegetation gives basic habitats for animal and other biological organisms. It is one of essential landscapes in river ecosystem. This floral study was conducted to give basic information for management of the Geum river ecosystem. We discovered total 69 plant communities out of 40 sites studied and mean 8 plant communities were analysed per study site. Salix koreensis and Salix subfragilis community were dominant of all communities at tree layer and Salix gracilistyla and Rubus parvifolius were dominant communities at shrub layer. Phalaris arundinacea, Phragmites japonica, Miscanthus sacchariflorus and Artemisia princeps var. orientalis appeared most as perennial grasses and Humulus japonicus, Persicaria thunbergii and Persicaria hydropiper appeared most as annual grasses. Robinia pseudoacacia, Amorpha fruticosa and Bidens frondosa were frequently present as exotic species. Grass communities were higher than tree communities because of human disturbance by artificial banks. The number of species was 182 appeared as 53 families 144 species, 34 varieties and 4 forma and mean species number was 25.5 per site. The most abundant site was Yanggang bridge site (14 vegetation association, 49 species) and the least abundant site was Namdaechon, Muju site (3 vegetation association, 12 species). We suggest that continuous riparian vegetation monitoring should be carried out to manage water environment ecologically.

• Journal of Korea Water Resources Association
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• v.55 no.12
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• pp.1065-1076
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• 2022

The purpose of this study was to investigate the effect of the expansion and withering of Salix subfragilis communities on the water quality in Namgang Dam reservoir. The distribution area of the Salix subfragilis communities was 0.12 km² in 2003 for the first time, but it was 3.58 km² in 2019, which has increased rapidly by about 30 times in 16 years. However, in 2013, the distribution area has decreased by 0.17 km² due to long-term immersion in high turbidity, and self-thinning in Salix subfragilis communities. The lake characteristics of reservoir showed a combination of lake type and river type in terms of average water depth, watershed area/lake surface area ratio, water residence time, flushing rate, and stratification. From the result of analyzing long-term changes in lake water quality, COD, TP, and chlorophyll-a in Salix subfragilis communities were significantly larger than those in the three points located in the central part of reservoir. In particular, the fact that the value of chlorophyll-a showed the maximum value in winter rather than summer, unlike the trend of the three points in the Namgang Dam water quality monitoring network, is thought to have occurred internally rather than externally. It can be estimated that one cause of this deterioration of the water quality in Namgang Dam reservoir is the huge amount of nutrients generated in the decomposition process of by-products such as fallen leaves, branches and withered trees in Salix subfragilis communities.

• Journal of the Korean Institute of Landscape Architecture
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• v.27 no.2
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• pp.58-68
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• 1999

This study was carried out to verify the distribution patterns of Salix gracilistyla and Phragmites japonica communities known as obligatory riparian species according to physical factors such as micro-landforms, substrates, etc., at Soo-ip stream corridor. Firstly four vegetation types - Salix gracilistyla dominant type, Phragmites japonica dominant type, mixed type of two species, and mixed type of two species to other species, were classified by cluster analysis based on UPGMA-Euclidean distance. Also these vegetation types showed many different distribution patterns in response to the longitudinal and lateral view along the stream corridor and substrate composition. Salix gracilistyla was major component of dominant vegetation types developed at attack point of bending reach and on substrates composed of rock fragments, but contrastly Phragmites japonica was most important component of dominant vegetation types at point bar of bending reach and floodplain, and on substrates composed of soil materials. Secondly the species and environment biplot form CCA strongly supported the vegetation types divided by classification. Namely Salix gracilistyla was closely correlated with rock fragments and steep slope, which is resistant to physical action even though located near running water. But Phragmites japonica showed a high correlation with soil particles sedimented at floodplain by divergent flow.

• Journal of Ecology and Environment
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• v.30 no.3
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• pp.251-255
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• 2007

Self-thinning was measured in Salix communities on Bam Island in Seoul at various age stages. $D^2H$ was used to estimate tree biomass, where D is stem diameter at breast height or 10 cm height for plants with height <1.5 m, and H is height. A log-log plot of density versus $D^2H$ and correlation analysis indicated a significant relationship between density and biomass with equation 'log $D^2H$ = -1.27 log N + 7.06'. This indicates that self-thinning affects biomass in the Salix community with -1.27 as the thinning coefficient. If we assume a thinning exponent -3/2, then the allometric coefficient of the equation, log w = a log $D^2H$ + b, is 1.18. This is much higher than that for any other species studied in Korea. There were statistically significant relationships between age and density and between age and basal area and these relationships suggest guidelines for transplantation of willows and for the assessment of Salix community restoration projects in riverine wetlands based on standard density, basal area, and age. The results of this study may also increase understanding of succession processes in Salix community restoration in riverine wetlands.

• Korean Journal of Plant Resources
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• v.20 no.3
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• pp.234-241
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• 2007

The present study was undertaken to classify and describe the riparian vegetation of the 6 river${\cdot}$stream of Korea Peninsula. As a result the vegetation was divided into nineteen communities. The vegetation units obtained in the present study were as follow: A: Salix koreensis community, B: Salix gracilistyla community, C: Robinia pseudo-acacia community, D: Amorpha fluticosa community, E: Brousonnetia papyrifera community, F: Phyllostachys bambusoides community, G: Rubus corchorifolius community, H: Phramities japonica community, I: Phramites communis community, J: Miscanthus sacchariflorus community, K: Miscanthus sinesis var. purpurascens community, L: Artemisia princeps var. orientalis community, M: Humulus japonicus community, N: Zoysia japonica community, O: Inperata cylindrica var. koenigii community, P: Agropyron tsukushiense var. transiens community, Q: Juncos effusus var. decipiens community, R: Rumex crispus community, S: Persicaria hydropiper community. The vegetation characteristics of riversides was recovered in the surveyed results according to river${\cdot}$stream basin, in other words, 10 communities in the upper river${\cdot}$stream riparian, 15 communities in the middle river${\cdot}$stream riparian, 10 communities in the down river${\cdot}$stream riparian. The Phragmites japonica community in the upper and Phragmites communis community in the down was analyzed by common community of the 6 river${\cdot}$stream riparian, respectively, but none in the middle. The standing profile of vegetation across 6 river${\cdot}$stream was seen stepwise Phragmites japonica community, Salix gracilistyla community, Miscanthus sinensis var. purpurascens community, shrub community by natural waterway in the upper, Salix gracilistyla community, Phragmites communis community, Rumex crispus community, Miscanthus sacchariflorus community, Humulus japonicus community in the middle, Phragmites communis community in the down. The differences of distributional featurs of vegetation emerged from the riparian of the 6 river${\cdot}$stream, but don't from the 6 river${\cdot}$stream.

• Journal of Wetlands Research
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• v.9 no.2
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• pp.33-43
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• 2007

Distribution area, actual vegetation map, standing crop biomass, relative growth, and primary productivity of Salix spp.were investigated to provide the basic data necessary for conservation and ecotechnological application of Salix community in the Upo wetland, Changryeong County, Gyeongsangnamdo Province, Korea from April 2005 to April 2006. 1. Among seven Salix species, the dominant species was S. nipponica and S. glandulosa was subdominant. There were six kinds of Salix communities such as S. nipponica, S. glandulosa, S. koreensis, S. nipponica-S. glandulosa, S. glandulosa-S. nipponica, and S. nipponica-S. koreensis. 2. Distribution area of S. nipponica community was largest as 28.46 ha among Salix communities and those of S. nipponica-S. glandulosa community, S. glandulosa-S. nipponica community, S. nipponica-S. koreensis community, S. glandulosa community, and S. koreensis community were 6.12 ha, 6.12 ha, 2.92 ha, 1.86 ha, and 0.81 ha, respectively. 3. The tree age, tree height, and DBH of S. nipponica were 5~13year, 4.1~7.2 m, and 3.0~14.0 cm and those of S. glandulosa were 2~36year, 3.5~10.1 m, and 3.2~26.0 cm, respectively. 4. The standing crop of S. nipponica was 408 ton and that of S. glandulosa was 336 ton in the study area. 5. The productivity of S. nipponica was $235g\;m^{-2}yr^{-1}$ and the annual production was 86.4 ton, and those of S. glandulosa were $1,006g\;m^{-2}yr^{-1}$ and 80.3 ton in the study area.

• Journal of Wetlands Research
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• v.23 no.3
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• pp.201-212
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• 2021

In wetland protection areas, a phytosociological research was conducted on willow forests, which plays an important ecological and environmental role and is the main material for ecological restoration. A total of 61 relevés were collected according to the Z-M(Zürich-Montpellier) school's method and the characteristics of plant communities and the composition of the species were identified. A total of 9 plant communities including 237 taxa were differentiated. Willow species showing the high r-NCD(relative net contribution degree) value in study areas were Salix koriyanagi, Salix chaenomeloides, Salix triandra subsp. nipponica, Salix gracilistyla and Salix pierotii. Poaceae was the most diverse in species, followed by Asteraceae, Apiaceae, Polygonaceae and Fabaceae. Life form type of willow forests in wetland protection areas was determined to be Th(therophytes)-R₅(non-clonal form)-D₄(clitochores)-e(erect form) type. The naturalized plants and invasive alien species were identified as 24 taxa and 4 taxa, respectively. Naturalized and disturbance indices were 10.1% and 41.4%, respectively. The results of the site-species ordination by Non-Metric Multidimensional Scaling(NMDS), wetland types and altitude gradient were the main ecological factors determining the spatial distribution of plant communities. Diversity index and evenness index were high in mountainous palustrine wetlands with relatively high altitude, and the disturbance index, naturalized index and appearance rate of annual plant were high in riverine and lacustrine wetlands with low altitude.

• Journal of Wetlands Research
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• v.12 no.1
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• pp.15-22
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• 2010

We measured net primary productivity, annual accumulation of organic carbon and leaf decomposition of Salix community in the flood plain of the Han River and the Nakdong River. Net primary productivity, annual accumulation of organic carbon of the Salix community were 22.5ton/ha/yr(16.7ton/ha/yr-31.2ton/ha/yr) and 9.7ton C/ha/yr(7.5ton C/ha/yr-14.0ton C/ha/yr) respectively, which showed the highest values among the woody plant communities reported in the Korea. It means that planting Salix in the flood plain of the river is the best way to remove carbon dioxides. The faster leaf decomposition occurred around, under and the herb of Salix community in order. Leaf decomposition rate of Salix was higher than that of mesophytes, but lower than that of hydrophytes.