• Journal of People, Plants, and Environment
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• v.24 no.2
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• pp.219-227
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• 2021

Background and objective: Urban street trees play an important role in carbon reduction in cities where greenspace is scarce. There are ongoing studies on carbon reduction by street trees. However, information on the carbon reduction capacity of street trees based on field surveys is still limited. This study aimed to quantify carbon uptake and storage by urban street trees and suggest a method to improve planting of trees in order to increase their carbon reduction capacity. Methods: The cities selected were Sejong, Chungju, and Jeonju among cities without research on carbon reduction, considering the regional distribution in Korea. In the cities, 155 sample sites were selected using systematic sampling to conduct a field survey on street environments and planting structures. The surveyed data included tree species, diameter at breast height (DBH), diameter at root collar (DRC), height, crown width, and vertical structures. The carbon uptake and storage per tree were calculated using the quantification models developed for the urban trees of each species. Results: The average carbon uptake and storage of street trees were approximately 7.2 ± 0.6 kg/tree/yr and 87.1 ± 10.2 kg/tree, respectively. The key factors determining carbon uptake and storage were tree size, vertical structure, the composition of tree species, and growth conditions. The annual total carbon uptake and storage were approximately 1,135.8 tons and 22,737.8 tons, respectively. The total carbon uptake was about the same amount as carbon emitted by 2,272 vehicles a year. Conclusion: This study has significance in providing the basic unit to quantify carbon uptake and storage of street trees based on field surveys. To improve the carbon reduction capacity of street trees, it is necessary to consider planning strategies such as securing and extending available grounds and spaces for high-density street trees with a multi-layered structure.

• Journal of Ecology and Environment
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• v.46 no.4
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• pp.324-333
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• 2022

Background: The Korean scarlet dwarf, Nannophya koreana Bae (Odonata: Libellulidae), is anendangered dragonfly with an increasing risk of extinction owing to rapid climate changes and human activities. To prevent extinction, the N. koreana population and their habitat should be protected. Therefore, suitable habitat evaluation is important to build the N. koreana restoration project. The habitat suitability index model (HSI) has been widely used for habitat evaluation in diverse organisms. Results: To build a suitable HSI model for N. koreana, 16 factors were examined by seven experienced researchers. A field survey for N. koreana observed sites and spatial analysis were conducted to improve the model. Five factors were finally selected by this procedure (crown density, open water surface, water depth, pioneer plant cover, and type of water source). Finally, the N. koreana HSI model was generated with the five adjusted factors based on interview, field survey, and spatial analysis. This model was validated by a current N. koreana habitat in 2021. With this model, 46 sites in Uljin-gun, Korea, were surveyed for N. koreana habitats; five sites were identified as core habitats and seven as potential core habitats. Conclusions: This model will serve as a strong foundation for the N. koreana restoration project and as a reference for future studies on N. koreana and other endangered insect populations. Further analysis and long-term data will improve the efficacy of this model and restore endangered wildlife.

• Journal of Environmental Science International
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• v.31 no.6
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• pp.479-490
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• 2022

This study was to evaluate the utilization of terrestrial light detection and ranging for forest inventory in coniferous forests. Heights and diameter of the stand trees were measured manually using the traditional measurement method and the method using terrestrial LiDAR. The results of two methods were compared and analyzed to evaluate accuracy and feasibility. The terrestrial LiDAR used fixed and handy types to compare the accuracy between different operational methods. Comparative analyses used a paired t-test and Bland-Altman plot analysis. In the case of tree heights, the average of difference between the traditional method and terrestrial LiDAR for each plot was 0.81 m, -0.07 m, and 0.13 m for fixed type; 2.88 m, 1.19 m, and 0.93 m for the handy type. In the case of tree diameter at breast height, the average value of the difference between traditional methods and terrestrial LiDAR for each plot was 0.13 cm, -0.66 cm, and -0.03 cm for fixed type; 2.36 cm, 2.13 cm, and 1.92 cm for the handy type. The values from the method using the fixed type was highly consistent with that using the traditional measurement methods; the average difference was closer to zero. The crown density influences the precision of the height measurement using terrestrial LiDAR in coniferous forests. Therefore, future studies should focus on verifying the accuracy of terrestrial LiDAR in forests and on expanding the utilization of terrestrial LiDARs according to their operational methods.

• Journal of The Geomorphological Association of Korea
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• v.27 no.3
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• pp.87-103
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• 2020

The purpose of this study is to evaluate the risk of cropland and man-made infrastructures in a landslide-prone area using a GIS-based method. To achieve this goal, a landslide inventory map was prepared based on aerial photograph analysis as well as field observations. A total of 550 landslides have been counted in the entire study area. For model analysis and validation, extracted landslides were randomly selected and divided into two groups. The landslide causative factors such as slope, aspect, curvature, topographic wetness index, elevation, forest type, forest crown density, geology, land-use, soil drainage, and soil texture were used in the analysis. Moreover, to identify the correlation between landslides and causative factors, pixels were divided into several classes and frequency ratio was also extracted. A landslide susceptibility map was constructed using a bayesian predictive model (BPM) based on the entire events. In the cross validation process, the landslide susceptibility map as well as observation data were plotted with a receiver operating characteristic (ROC) curve then the area under the curve (AUC) was calculated and tried to extract a success rate curve. The results showed that, the BPM produced 85.8% accuracy. We believed that the model was acceptable for the landslide susceptibility analysis of the study area. In addition, for risk assessment, monetary value (local) and vulnerability scale were added for each social thematic data layers, which were then converted into US dollar considering landslide occurrence time. Moreover, the total number of the study area pixels and predictive landslide affected pixels were considered for making a probability table. Matching with the affected number, 5,000 landslide pixels were assumed to run for final calculation. Based on the result, cropland showed the estimated total risk as US $ 35.4 million and man-made infrastructure risk amounted to US $ 39.3 million.

• Journal of The Geomorphological Association of Korea
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• v.26 no.3
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• pp.53-67
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• 2019

The purpose of this study is to identify the quality of landslide susceptibility in a landslide-prone area (Jinbu-myeon, Gangwon-do, South Korea) by spatial prediction modeling approach and compare the results obtained. For this goal, a landslide inventory map was prepared mainly based on past historical information and aerial photographs analysis (Daum Map, 2008), as well as some field observation. Altogether, 550 landslides were counted at the whole study area. Among them, 182 landslides are debris flow and each group of landslides was constructed in the inventory map separately. Then, the landslide inventory was randomly selected through Excel; 50% landslide was used for model analysis and the remaining 50% was used for validation purpose. Total 12 contributing factors, such as slope, aspect, curvature, topographic wetness index (TWI), elevation, forest type, forest timber diameter, forest crown density, geology, landuse, soil depth, and soil drainage were used in the analysis. Moreover, to find out the co-relation between landslide causative factors and incidents landslide, pixels were divided into several classes and frequency ratio for individual class was extracted. Eventually, six landslide susceptibility maps were constructed using the Bayesian Predictive Discriminant (BPD), Empirical Likelihood Ratio (ELR), and Linear Regression Method (LRM) models based on different category dada. Finally, in the cross validation process, landslide susceptibility map was plotted with a receiver operating characteristic (ROC) curve and calculated the area under the curve (AUC) and tried to extract success rate curve. The result showed that Bayesian, likelihood and linear models were of 85.52%, 85.23%, and 83.49% accuracy respectively for total data. Subsequently, in the category of debris flow landslide, results are little better compare with total data and its contained 86.33%, 85.53% and 84.17% accuracy. It means all three models were reasonable methods for landslide susceptibility analysis. The models have proved to produce reliable predictions for regional spatial planning or land-use planning.

• Journal of The Geomorphological Association of Korea
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• v.27 no.2
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• pp.65-80
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• 2020

This paper deals with risk assessment of life in a landslide-prone area by a GIS-based modeling method. Landslide susceptibility maps can provide a probability of landslide prone areas to mitigate or proper control this problems and to take any development plan and disaster management. A landslide inventory map of the study area was prepared based on past historical information and aerial photography analysis. A total of 550 landslides have been counted at the whole study area. The extracted landslides were randomly selected and divided into two different groups, 50% of the landslides were used for model calibration and the other were used for validation purpose. Eleven causative factors (continuous and thematic) such as slope, aspect, curvature, topographic wetness index, elevation, forest type, forest crown density, geology, land-use, soil drainage, and soil texture were used in hazard analysis. The correlation between landslides and these factors, pixels were divided into several classes and frequency ratio was also extracted. Eventually, a landslide susceptibility map was constructed using a logistic regression model based on entire events. Moreover, the landslide susceptibility map was plotted with a receiver operating characteristic (ROC) curve and calculated the area under the curve (AUC) and tried to extract a success rate curve. Based on the results, logistic regression produced an 85.18% accuracy, so we believed that the model was reliable and acceptable for the landslide susceptibility analysis on the study area. In addition, for risk assessment, vulnerability scale were added for social thematic data layer. The study area predictive landslide affected pixels 2,000 and 5,000 were also calculated for making a probability table. In final calculation, the 2,000 predictive landslide affected pixels were assumed to run. The total population causalities were estimated as 7.75 person that was relatively close to the actual number published in Korean Annual Disaster Report, 2006.

• Journal of Korean Society of Forest Science
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• v.107 no.1
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• pp.1-15
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• 2018

In order to determine the effects of thinning on mushroom fruiting, microclimate and air temperature in Quercus mongolica forests, this study investigated changes in crown density, soil temperature, air temperature and throughfall in the natural Q. mongolica forest which was thinned by approximately 45% four years ago. The results showed that crown density was smaller than control by 6% from April to October, The soil temperature and air temperature in the thinned stands were significantly higher than those of the control by $1{\sim}2^{\circ}C$ until August and differences in air and soil temperature. The average daily temperature difference was higher than control by $0.2{\sim}0.7^{\circ}C$ until October. Throughfall from July to September in the thinned was approximately 135 mm higher than in the control. The maximum difference in throughfall per unit time was 3.5 mm/h. Soil moisture in the thinned site increased by approximately 5% compared with the control and reduced to the normal moisture after 4 days in both sites. 55 mushroom species were found in the thinned area between July and September. The thinned site contained 10 mycorrhizal mushrooms more than the control and 1 saprophytic mushroom species more than the control. Shannon-Wiener Index was 3.2, approximately 0.5 higher than the control. Tylopilus neofelleus, etc., occurred in the thinned site more quickly, but Aaricus subrutilescens, Clitocybe sp, occurred later. In the thinned site, the dominance of Tylopilus neofellelus and Armillaria sp. increased approximately 6% and 30% and yield about 1.5 times and 20 times, respectively. In conclusion, thinning in the Q. mongolica forest increased the soil and air temperature, soil moisture, throughfall and the diversity of mushroom species, and advanced the period of occurrence, and increased dominance and yield of some mycorrhizal mushrooms and Amillaria sp.

• Korean Journal of Environment and Ecology
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• v.24 no.2
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• pp.157-165
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• 2010

This study was carried out to suggest the basic data of planting method for construction of buffer green space based on the land use in case of reclaimed land by analyzing land structure, planting concept, and planting structure in buffer green space, Rokko Island, Kobe, Japan. Rokko Island(total area: 580ha) is divided into port and logistics industry area and urban area by constructing the box type large-scale buffer green space. The land structure of buffer green space were biased mounding type, parallel mounding type, and complex mounding type. The width of buffer green space was 50meters in case of northern area, from 28 to 32meters in case of eastern area, and 37.5meters in case of western area, and the slope of that was from 18 to 25 degrees and the height of that was from 2 to 15meters. There were applied landscape and buffer planting concept on the sea side area of northern buffer green space, on the other hand landscape and shade planting concept on the Inner city side area of that. According to the result of planting structure analysis of northern buffer green space, the main woody species were those of deciduous-evergreen species grow in warm-temperate forest zone such as Quercus glauca, Cinnamomum camphora, Machilus thunbergii, Elaeagnus maritima. The results of maximum number of species and planting density by $100mm^2$ was that 9 species 22 individuals in canopy layer, 9 species 15 individuals in understory layer, 3 species 67 individuals in shrub layer, and 14 species 104 individuals in total. The plant coverage of northern buffer green space based on the ecological planting method was from 69 to 139% in case of canopy layer, from 26 to 38% in case of understory layer, from 6 to 7% in case of shrub layer, and from 101 to 184% in total. Index of plant crown volume of northern buffer green space based on the ecological planting method was from 1.40 to $3.12m^3/m^2$ in case of canopy layer, from 0.43 to $0.55m^3/m^2$ in case of understory layer, $0.06m^3/m^2$ in case of shrub layer, and from 1.89 to $3.73m^3/m^2$ in total.

• Journal of Korean Society of Forest Science
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• v.81 no.4
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• pp.303-309
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• 1992

This study eras carried out to investigate the ecological changes on the plant community at erosion controlled area in Yoju-gun, Kyonggi-do. The results of the study were as follows : 1. The depth of organic matters in the soil profile from 4 to 14 years was estimated to be $Y_{(cm)}=0.436X_{(yr)}-0.931$(r=0.978), and 02 layer was $Y_{(cm)}=0.339_{(yr)}-0.931$ (r=0.954). 2. On upper plant layer. Alnus spp. was decreased, on an average, 32% of relative coverage, 12.4% of relative density and 16.8% of relative frequency in each plot for 3 years, as this area was damaged by Agelastica coerulea Baly for 2-3 years. 3. On upper plant layer, relative coverage of Pinus spp. was increased after 6, 7 years in erosion controlled area and was taked the highest plant (more then 40%) from 10 to 14 years. 4. On lower plant layer, relative density of Quercus ssp. (these species has not been planted and sown on erosin controlling) was increased all the plot. 5. The increase of the whole crown projection area was estimated to be $Y_{(m^2)}=18.020X_{(yr)}+18.834$(r=0.954) 6. The biomass was estimated to be 14.88t/ha on elapsed 6 years, 22.84t/ha on 8 years, 35.08t/ha on 10 years, 47.80t/ha on 12 years, 58.13t/ha on 14 years.

• The Korean Journal of Ecology
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• v.28 no.3
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• pp.141-147
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• 2005

To clarify seed distribution in sediment and its burial properties of Suaeda japonica, the vertical and horizontal distribution of seeds, organic content of sediment, and sediment content delivered by crabs were studied in mud tidal-flat of Walgot-dong, Siheung, Gyeonggi Province, from March 1999 to October 2000. The 94% and 6% of S. japonica seeds were buried under and outside the maternal plant crown, respectively. Organic matter contents of sediment were higher at the area (17%) covered than at the one (8%) uncovered by S. japonica. In the area covered by S. suaeda, organic matter profiles of sediment showed vertical variation from 19% in surface (1 cm depth) to 14% in 6 cm depth. S. japonica seeds buried in sediment decreased from 45% in 2 mm depth to 0% in 12 mm depth. The density of crabs was higher in the vegetated area than in the non-vegetated one. Especially, the density of Cleistostoma was about 8 times higher in the former than in the latter In the vegetated area, the amount of sediment delivered by crabs was estimated to be 2,409 $cm^3{\cdot}m^{-2}$, and this could ascend the height of sediment to 2.4 mm. Consequently, it might be interpreted that plant debris (organic matters) of maternal plants and sediment delivered by crabs made the S. japonica seeds bury well. By relationship between crab distribution and vegetation, it was thought that crabs got a benefit from S. japonica.