• Proceedings of The Korean Society of Agricultural and Forest Meteorology Conference
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• 2005.09a
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• pp.19-20
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• 2005

• Proceedings of The Korean Society of Agricultural and Forest Meteorology Conference
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• 2015.08a
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• pp.59-63
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• 2015

• Journal of Korea Water Resources Association
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• v.52 no.spc2
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• pp.777-789
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• 2019

The purpose of this study is to evaluate changes in water quality and aquatic ecosystem health by additional dam release of stream maintenance flow from multipurpose dams in Han river basin ($34,148km^2$) using SWAT (Soil and Water Assessment Tool). The period of additional release was spring (April to June) and autumn (August to October) to evaluate the changes with the data of aquatic ecosystem health survey. The amount of additional release was set proportional to the present dam release, and the maximum release amount was controlled not to exceed the officially notified stream maintenance flow from dam. The 10 percent to 50 percent additional releases showed that the stream water quality (T-N, $NH_4$, T-P, and $PO_4-P$) concentrations except $NO_3-N$ decreased in spring while increased in autumn period. Using the stream water quality results and applying with Random Forest algorithm, the grade of aquatic ecosystem health index (FAI, TDI, and BMI) was improved for both periods especially in the downstream of basin. This study showed that the additional release of stream maintenance flow was more effective in spring than autumn period for the improvement of water quality and aquatic ecosystem.

• Korean Journal of Agricultural and Forest Meteorology
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• v.18 no.4
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• pp.348-356
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• 2016

Carbon dioxide ($CO_2$) gases concentration in atmosphere has been growing since preindustrial times. By sequestering a large amount of atmospheric carbon (C), terrestrial ecosystems are thought to offer a mitigation strategy for reducing global warming. Woody agro-ecosystems such as fruit tree are among the least quantified and most uncertain elements in the terrestrial carbon cycle. $CO_2$ and energy fluxes were measured by the eddy covariance method on a 15-year old apple orchard of South Korea in 2006. Environmental parameters (net radiation, precipitation, etc.) were measured along with fluxes. The results showed that during late June, the ability to sequestrate C was significant at an apple orchard ecosystem and it reached on the peak of $-6.5g\;C\;m^{-2}\;d^{-1}$. We found that in the apple orchard, the daily average of net ecosystem exchange of $CO_2$ (NEE) and cumulative NEE on a yearly basis were $-1.1g\;C\;m^{-2}$ and $-396.9g\;C\;m^{-2}$, respectively. These results reveal that there is high carbon sequestration in the apple orchard of South Korea, which is the same magnitude with repect to that of a natural forested ecosystem of the same biome rank (temperate-humid deciduous forest).

• Proceedings of the KSRS Conference
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• v.2
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• pp.543-546
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• 2006

NDVI has been very frequently used to estimate several biophysical parameters that are required for ecosystem models. Leaf area index (LAI), canopy closure, and biomass are among those biophysical parameters that are estimated by empirical relationship with NDVI. However, the type of remote sensing signals (raw DN value, at-sensor radiance, atmospherically corrected reflectance) used can vary the calculation of NDVI. In this study, we tried to attempt to compare the influence of NDVI linked with forest LAI for the watershed-scale ecosystem models to estimate evapotranspiration. Landsat ETM+ data were used to obtain various NDVI values over the study area in central Korea. The NDVI-based LAI and the resultant evapotranspiration estimation were greatly varied by the remote sensing signal applied.

• The Korean Journal of Ecology
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• v.23 no.2
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• pp.131-134
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• 2000

Forest vegetation in Korea can be largely divided into warm temperate, cool temperate and frigid forest zone. The cool temperate forest zone of them occupies the largest part of the Korean peninsula and it is generally divided into three subdivisions such as northern, central and southern subzone. The Forestry Research Institute established three long-term ecological research sites at Kwangnung Experiment Forest in the central subzone of the cool temperate forest zone, at the Mt. Kyebangsan Forest in the northern subzone of the cool temperate forest zone. and at the Mt. Keumsan Forest in the warm temperate forest zone. The objectives of long-term ecological research in the Forestry Research Institute, Korea are to study long-term changes of the forest ecosystems in energy fluxes, water and nutrient cycling, forest stand structure, biological diversity, to quantify nutrient budgets and fluxes among forest ecosystem compartments and to integrate ecological data with a GIS - assisted model. To achieve the objectives, forest stand dynamics. environmental changes in soil properties, stream water quality, nutrient cycling, air pollution and biological diversity have been investigated and plant phonology as an indicator of climate change has been monitored in the LTER sites.

• Journal of Korean Society of Forest Science
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• v.96 no.5
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• pp.572-579
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• 2007

Tree species diversity is an important aspect of forest ecosystem stability. Tree species inventories at defined sites and in minimum diameter classes give a reliable indicator of the diversity level as well as the structural stability level of a study site. This study was conducted to investigate the species composition and the stand structure of the natural forest, timber-harvested forest (logged-over forest) and degraded forest of the Oak-twin Township in the Bago Yoma Region of Myanmar. Natural forest showed the highest family and species richness in all the investigated forests. At the family level, Verbenaceae occupied the highest importance value index (IVI) in all the forest stands while teak (Tectona grandis Linn. f.) occupied the highest IVI at the species level. However, the small diameter classes of T. grandis and other commercial species were less than those of big diameter classes in all the investigated forests. This abnormal pattern of diameter distribution could be a problem for the sustainable production of commercial timber species in the near future.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.8 no.3
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• pp.73-85
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• 2005

Natural disturbance and environmental pressure on natural ecosystems are gradually increasing, and the cause is significantly related to large-scale environmental pollution, global warming, decreasing biodiversity and habitat fragmentation. Environmental impact assessment(EIA) in Korea has been focused on distribution and composition of fauna and flora as major evaluation aspects in ecosystem assessment. It is well known that those characteristics of flora and fauna strongly depend on characteristics and quality of habitat and ecosystem. However, there is no items to assess habitat and ecosystems of spatial ecological system in EIA. Many countries are trying to develop the EIA items to consider the spatial characteristics of habitat and ecosystem and those ecological dynamics as well as species level. In this stream, landscape ecology is emerging discipline to examine spatial pattern and ecological process within/between habitats and ecosystems. Landscape ecological analysis, as a special tool for ecosystem evaluation, has been appropriately adopted to the EIA system in the advanced countries. This review paper tries to introducing the possibilities of landscape ecological concept into the Korean EIA system.

• Journal of the Korean Institute of Landscape Architecture
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• v.32 no.5
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• pp.102-118
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• 2004

The purpose of this study was to propose an ecological management plan by the comprehensive analysis of biotope structures on Namsan Urban Natural Park in Seoul. Classified by actual vegetation, structure of layer and vegetation damage, biotope structures were composed of forest area, compact management area, herb area, cultivated area and non-ecology(urban) area. Succession had seened to stop in the Native forest. Artifical forest was divided into two types. The first, upper layer, was too dense to accommodate lower layer plants, the other case was the appearance of Quercus spp. and the first stage plants of succession following the declination of the upper layer plants. The soil pH of Nam-san Urban Park was 4.21∼4.51, which meant the soil was becoming acid. As the result of acidity, leaching of available nutrition(K/sup +/, NH₄/sup +/, Ca/sup ++/ etc.) was immediately influenced by the natural ecosystem, influence of acid rain was disturbed to becoming organic matter which was use to plants. In the case of a biotope structure management plan, the urban area was prohibited to spread outside. Cultivated and herb area was regenerated to natural forest. In the forest area, the compact management area was maintained with its present condition, and then it is desirable to make a preservation area and to plant shrubs. Planted Pinus densiflora Community was needed to eliminate competitive species of canopy layer, and plant shrubs. Management of deciduous broad-leaved Comm. was maintained in its present conditionand it is desirable to raise the diversity of the understory and shrub layer. The management of the artifical forest seems to be suitable for Q. spp. community. The care of naturalized plants prevents the expansion and restores the structure of wild plants. The soil management was a marked restoration soil ecosystem in order to prevent soil acid and drying.

• Journal of Ecology and Environment
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• v.43 no.4
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• pp.364-375
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• 2019

Background: Ecologists continue to investigate the factors that potentially affect the pattern and magnitude of tree damage during catastrophic windstorms in forests. However, there still is a paucity of research on which trees are more vulnerable to direct damage by winds rather than being knocked down by the fall of another tree. We evaluated this question in a mixed hardwood-softwood forest within the Big Thicket National Preserve (BTNP) of southeast Texas, USA, which was substantially impacted by Hurricane Rita in September 2005. Results: We showed that multiple factors, including tree height, shade-tolerance, height-to-diameter ratio, and neighborhood density (i.e., pre-Rita stem distribution) significantly explained the susceptibility of trees to direct storm damage. We also found that no single factor had pervasive importance over the others and, instead, that all factors were tightly intertwined in a complex way, such that they often complemented each other, and that they contributed simultaneously to the overall susceptibility to and patterns of windstorm damage in the BTNP. Conclusions: Directly damaged trees greatly influence the forest by causing secondary damage to other trees. We propose that directly and indirectly damaged (or susceptible) trees should be considered separately when assessing or predicting the impact of windstorms on a forest ecosystem; to better predict the pathways of community structure reorganization and guide forest management and conservation practices. Forest managers are recommended to adopt a holistic view that considers and combines various components of the forest ecosystem when establishing strategies for mitigating the impact of catastrophic winds.