• Korean Journal of Environment and Ecology
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• v.35 no.4
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• pp.408-423
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• 2021

We established and monitored survey sites in seven regions of Mt. Jiri to investigate population decline and change of the Korean fir (Abies koreana) over a ten-year period from 2009 to 2018. With the exception of one site (Seseok), the six remaining ones all showed a four-layer stratification structure. The importance value of Korean firs in all of the survey areas decreased significantly by 28.5%, from 55.7% in 2009 to 39.8% in 2018. The average population of objects with a diameter at breast height (DBH) of 5cm or more in all survey sites was 711 objects/ha in 2018, and the cumulative death rate from 2009 to 2018 was 10.8%. Among the death types, DS (dead standing) was the most dominant, comprising 82.4% of the total survey area. However, in Banyabong 1, which had a high gradient of 35°, the death types other than DS accounted for 44.2%. We estimate that A. koreana can maintain a stable population as its distribution type for each diameter class in the Saeseokpyeongjeon site showed a reverse-J shape. The average annual ring growth in all survey sites was 1.09 mm/year, with the most abundant growth observed in the Seseokpyeongjeon site, which was formed mainly by a subtree layer. The growth ring survey showed the estimated average age of A. koreana population in the Byeoksoryeong and Banyabong 1 sites to be 102 and 91 years, respectively, a general downward trend of vitality since 2013.

• Journal of Korean Society of Forest Science
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• v.98 no.6
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• pp.772-779
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• 2009

This study was conducted to estimate the carbon (C) contents in pure and mixed stands of pine (Pinus densiflora) and oak (Quercus spp.) trees for establishing the C inventory of forest ecosystems. A total of fifteen 20 m${\times}$20 m pure and mixed stands of pine and oak trees were chosen in natural forests in Hoengseong, Kangwon based on the basal area of all trees ${\geq}$ 5 cm DBH: three of 95% of pine and 5% oak trees [pine stand], three of 100% of oak trees [oak stand], and nine of 20 to 70% of pine and 80 to 30% of oak trees [mixed stand]. To estimate C contents in the study stands, biomass in vegetation, forest floor and coarse woody debris (CWD) were calculated and C concentrations in vegetation, forest floor, CWD and soil (0-30 cm) were analyzed. There was no significant difference in vegetation C contents among the stands; 147.6 Mg C/ha for the oak stand, 141.4 Mg C/ha for the pine stand and 115.8 Mg C/ha for the mixed stand. Forest floor C contents were significantly different among the stands (p<0.05); 12.7 Mg/ha for the pine stand, 9.9 Mg/ha for the oak stand, and 8.4 Mg/ha for the mixed stand. However, CWD C contents were not significantly different among the stands (p>0.05); 2.2 Mg/ha for the mixed stand, 1.7 Mg/ha for the oak stand, and 1.1 Mg/ha for the pine stand. Soil C contents up to 30 cm depth were not significantly different among the study stands; 44.4 Mg C/ha for the pine stand, 41.6 Mg C/ha for the mixed stand, and 33.3 Mg C/ha for the oak stand. Total ecosystem C contents were lower in the mixed stand than those in the pure stands, because vegetation C contents which occupied almost total ecosystem C contents were lower in the mixed stand than those in the pure stands; 199.6 Mg C/ha for the pine stand, 192.5 Mg C/ha for the oak stand and 169.1 Mg C/ha for the mixed stand. Lower vegetation C contents in the mixed stand might be influenced by interspecific competition between pine and oak trees and intraspecific competition among the oak trees resulted from high stand density. We suggest that forest management such as thinning to enhance C storage is indispensible for minimizing the competition in forest ecosystems.

• Korean Journal of Environment and Ecology
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• v.22 no.5
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• pp.514-520
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• 2008

The permanent monitoring plots were installed in 2001 for long-term monitoring the structure of forest communities at the Piagol(Valley) and Daeseonggol(Valley) in the Jirisan National Park, and monitored the forest structure in the studied sites in 2001 and 2006. Dominant species at Piagol and Daeseonggol was Carpinuslaxiflora and Quercus mongolica respectively. Based on the distribution of major species' stem diameter, the species diversity index was higher in Piagol than that of Daeseonggol. The distribution of diameter in major tree species in the studied sites showed a stable plant community structure. The forest of Piagol, which is positioned in the valley, showed a quite a different composition of species from that of Daeseonggol, which is positioned on the slope. In the last five years, the overall grows rate of Piagol Forest decreased by $6.4m^2$ per hectare, while Daeseonggol Forest increased by about $8.27m^2$ per hectare. I think that this is because of the fact that a lot of large old trees have died.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.39 no.4
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• pp.211-221
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• 2021

The Rabbit grass(Trifolium Repens, call it 'Clover') is a representative harmful plant of lawn, and it starts growing earlier than lawn, forming a water pipe on top of the lawn and hindering the photosynthesis and growth of the lawn. As a result, in competition between lawn and clover, clover territory spreads, but lawn is damaged and dried up. Damage to the affected lawn area will accelerate during the rainy season as well as during the plant's rear stage, spreading the area where soil is exposed. Therefore, the restoration of damaged lawn is causing psychological stress and a lot of economic burden. The purpose of this study is to distinguish clover which is a representative harmful plant on lawn, to identify the distribution of damaged areas due to the spread of clover, and to review of changes in vegetation before and after the eradication of clover. For this purpose, a time series analysis of three vegetation indices calculated based on images of convergence Drone with RGB(Red Green Blue) and BG-NIR(Near Infra Red)sensors was reviewed to identify the separation between lawn and clover for selective eradication, and the distribution of damaged lawn for recovery plan. In particular, examined timeseries changes in the ecology of clover before and after the weed-whacking by manual and brush cutter. And also, the method of distinguishing lawn from clover was explored during the mid-year period of growth of the two plants. This study shows that the time series analysis of the MGRVI(Modified Green-Red Vegetation Index), NDVI(Normalized Difference Vegetation Index), and MSAVI(Modified Soil Adjusted Vegetation Index) indices of drone-based RGB and BG-NIR images according to the growth characteristics between lawn and clover can confirm the availability of change trends after lawn damage and clover eradication.

• Korean Journal of Environment and Ecology
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• v.21 no.2
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• pp.161-167
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• 2007

To investigate the structure and the conservation strategy of Korean native species, the Abies koreana forest at sub-alpine zone centering on the Witsaeorum(1,714m) shelter in Hallasan National Park was selected for a survey subject with 20 plots $(10{\times}10m)$ set up with random sampling method. Mean importance percent(MIP) of Abies koreana showed the highest numerical value-57.7%, and that of faxus cuspidata was the next value-16.2%. High positive correlations were shown between Taxus cuspidata and Prunus maximowiczii, Euonymus alatus; Betula ermani and Berberis amurensis var. quelpaertensis, Prunus sargentii; Prunus maximowiczii and Euonymus alatus; Berberis amurensis var. quelpaertensis and Prunus sargentii. Vigor of Abies koreana was so low that as much as 6.44% of total number of Abies Koreana investigated were dead. DBH of dead individuals ranged mainly from 5cm to 15cm.

• Journal of the Korean Geosynthetics Society
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• v.14 no.2
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• pp.71-79
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• 2015

This paper describes vegetation based soil-media hydroseeding measures that have been previously applied as slope revegetation methods show problems such as insufficient binding force, drying, and insufficient organic matter. In particular, in the case of slope faces in regions where scattering is severe, a vicious circle exists in which remarkably low vegetation cover rates and increases in withering rates over time lead to further decreases in vegetation cover rates, which lead to further increases in erosion and scattering. Therefore, in the present study, environment friendly soil stabilizers were applied for resistance against erosion or scattering and engineering evaluations such as long-term immersion tests and flow resistance tests were conducted to determine appropriate mixing ratios. According to the results of long-term immersion tests utilizing environment friendly soil stabilizers and existing greening soil based materials, 100% collapse occurred at 30 hours and 40 days in the case of soil stabilizer mixing ratios of 0% and 2%, respectively. While the original form of the samples remained intact until the experiment was completed in the case of mixing ratios exceeding 4% indicating that 2% or higher soil stabilizer mixing ratios could affect the maintenance of forms even under extreme conditions. In addition, artificial rainfall tests were conducted on 40, 45, and 55 degree slope faces to evaluate the structural stability of vegetation based materials. Flow resistance tests were conducted on soil stabilizer mixing ratios of 0, 4, 8% to evaluate erosion resistance capability. Based on the results of the tests, environment friendly soil stabilizers applied for prevention of scattering or resistance against erosion by rainwater are considered to provide large effects to reduce losses and loss rates showed a tendency of decreasing rapidly when soil stabilizers were mixed.

• Korean Journal of Environment and Ecology
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• v.5 no.1
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• pp.25-31
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• 1991

To investigate the structure and the conservation of Abies koreana forest at Banyabong area in Chirisan, 38 plots(100$m^2$) set up with random sampling method. Dead individuals of Abies koreana were 12.81%. were observed mainly upper-layer trees. A few seedlings of Abies koreana were observed. Three groups were classified by cluster analysis. High positive correlations was proved between Abies koreana and Rhododendron mucrolunulatum var. ciliatum, and High negative correlations was proved between Abies koreana and Fraxinus sieboliana, Carpinus cordata, Sasa purpurascens and Cornus controversa. Species diversity(H') of investigated area was calculated 1.9796-2.7509. To conserve Abies koreana forest at Banyabong area in Chirisan. Research and prescription on the declining of Abies koreana was needed and Quercus mongolica, Acer pseudo-sieboldianum, Fraxinus sieboliana, Carpinus cordata, Sasa purpurascens and Cornus controversa in the Abies koreana forest should be cleared out.

• Journal of Korean Society of Forest Science
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• v.99 no.4
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• pp.590-596
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• 2010

To investigate and to compare the structure of Picea jezoensis forests at Chunwangbong area in the Jirisan National Park, 33 plots(400) were set up by a random sampling method. Dead individuals of Picea jezoensis trees were 15.6%, these were observed mainly in the upper-layer trees. A few seedlings of Picea jezoensis were found in this investigation area. This result indicates that Picea jezoensis might be gradually decreased in the future. Picea jezoensis stands were classified into two major groups by cluster analysis. There were strong positive correlations between Syringa reticulata and Acer pseudosieboldianum, Tripterygium regelii, Quercus serrata; Betula ermani and Lonicera maackii; Euonymus macropterus and Acer ukurunduense; Acer pseudosieboldianum and Tripterygium regelii, and relatively weak negative correlations were showed between Picea jezoensis and Abies koreana; Betula ermani and Acer ukurunduense; Acer pseudosieboldianum and Tripterygium regelii. Species diversity index(H') of investigated groups ranged from 1.0000 to 1.3010.

• Korean Journal of Environment and Ecology
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• v.27 no.6
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• pp.704-717
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• 2013

This study aims to provide basic data for management and prevention of infection damage by Oak wilt disease through mapping method of status with infected level in damaged area of Bukhansan National Park. Survey was carried out in the distributed area of oak trees with mapping unit of polygon of actual vegetation and mapped of infection ratio and infection index applying weight according to infected level. Infection ratio of oak trees in Bukhansan National Park was 58.5%, and lightly damaged ratio was 29.6%, half of the damaged ratio was 16.1%, seriously damaged ratio was 8.8% and withered ratio was 4.1%. It was serious to be infected from Beomgol ridge in Wondobong district to Hyeongjaebong in Jeongrung district. Although the infected ratio of the western part of Songchu district, Sanseong district and Gugi district centering main ridge of Bukhansan National Park was low, it of ridge and main valley was high. Infection index of hardly damaged area was 39.1% of whole area, and slightly damaged area was 41.0%, half of the damaged area was 16.1%, seriously damaged area was 3.3% and alarmed withering area was 0.4%. Infection index was high around Musugol valley in Dobong district and Jaunbong, and it of Bohyunbong of Jeongrung district and the part of Hyojari valley of Sanseong district was serious. Predicted numbers of the trees affected Oak wilt disease compared to the distributed area of oak trees was 1,585,937 trees among 2,709,147 trees of Quercus spp. 352,931 trees among the 306,161 trees of oak were infected in Woi district, the most seriously infected area and 53,141 trees among the 145,747 trees of oak was infected in Gugi district, the most slightly infected area.

• Journal of Korean Society of Forest Science
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• v.99 no.4
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• pp.553-558
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• 2010

This study was conducted to clarify the differences in rodents population densities between natural restored and red pine silvicultured forests after forest fire in Samcheok, Gangwon Province, Korea from March to December 2008. One ha size of 3 study plots were set up in each natural restored and silvicultured stand. We trapped the small rodents during 4 consecutive nights every 2 months in each stand. Understory coverage and number of shrub stems were higher in silvicultured stand than in natural restored stand. Coverage of overstory, suboverstory and midstory, number of tree stem, woody seedling stems and dead wood, and amount of coarse woody debris were higher in natural restored stand than in silvicultured stand. Six hundred eighty eight individuals of four species, such as Apodemus agrarius, A. peninsulae, Eothenomys regulus and Tamias sibiricus were captured in our study. Number of captured small rodents were higher in natural restored stand than in silvicultured stand. Also, species compositions were differed in both stands. The captured number of A. agrarius and A. peninsulae were most highest in April and December. E. regulus were shown higher number of captured in April and June, and T. sibiricus were in June and October. Removal of coarse woody debris and silvicultural practice would not be good for the inhabitation of small rodents. For the conservation of small rodents diversity, management of understory and canopy would be needed in forest fired area.