• Korean Journal of Environment and Ecology
• /
• v.23 no.4
• /
• pp.365-375
• /
• 2009

The growth characteristics of Pinus thunbergii windbreak forest around Goosipo Beach, Sangha-Myon, Gochang-Gun, Jeollabuk-Do have been investigated, and the results are summarized as follows. The soil in the site was light acid sand with pH 5.7, and the mean sodium concentration of soils was 1.42dS/m. The tree diameter, height, crown width, and shape ratio(Height/DBH) were better with tree density was coming lower. Especially, the rate of shape ratio under 60 was more in sites with low tree density. This demonstrated that the trees have grown more soundly when the tree density was lower. The direction of main winds and distribution ratio of tree inclination had a correlation. The inclined trees are seemed to be influenced by main winds when they were younger and by Typhoon partly. Eighty one vascular plant species were found in the sites, and more number of herbaceous plants (57 taxa) lived there than woody plants (24 taxa). And more plant species of dune were found at the site where dune have developed well. Some thinning works need at high tree density areas in order to ensure effects of coastal windbreak.

• Journal of the Korean Geotechnical Society
• /
• v.17 no.6
• /
• pp.15-24
• /
• 2001

In order to evaluate undrained shear strength of clayey soils using Piezocone Penetration Test (CPTu), piezoncone factor is utilized. Commonly, piezoncone factors determined by empirical basis were preferred, which were established by correlation between measurements of piezocone test and undrained strengths obtained from other shearing tests. However, previous studies on the empirical piezocone factors were site-specific and there have been no systematic investigations on the effect of both engineering characteristics of clayey soils and soil non-homogeneity on the piezocone factor. Accordingly, the direct application of the previous results to Korean clayey soils without verification may be inappropriate. In this study, empirical piezocone factors are evaluated by comparing 46 CPTu results of 10 test sites with undrained shear strength obtained from Field Vane Test (FVT) and laboratory triaxial tests. Their reliabilities are investigated by the comparison with the previous piezocone factors and the deviation of data distribution from the mean values. And the effects of referencing test methods and typical engineering characteristics of clayey soils such as overconsolidation ratio (OCR) and plastic Index (I$_{p}$) are examined. Because piezocone factors obtained for various soil conditions are widely distributed, it is not appropriate to use the mean value as a representative. Instead, it is recommended to apply the piezocone factors with OCR, which is found to be a major factor in deriving piezocone factor. The necessitated piezocone factors are presented.d.

• Journal of the Korean Geotechnical Society
• /
• v.20 no.3
• /
• pp.129-139
• /
• 2004

During the construction of circular underground pipe, the non-proper compaction along the pipe and the decrease of compaction efficiency have been the main problems to induce the failure of underground pipe or facility. The use of CLSM (controlled low strength materials) should be one of the possible applications to overcome those problems. In this research, the small-scaled model test and the numeric analysis using PENTAGON-3D FEM program were carried out for three different cases on the change of backfill materials, including the common sand, the soil from construction site, and the CLSM.. From the model test in the lab, it was found out that the use of CLSM as backfill materials reduced the vertical and lateral deformation of the pipe, as well as the deformation of the gound surface. The main reason for reducing the deformation would be the characteristics of the CLSM, especially self-leveling and self-hardening properties. The measured earth pressure at the surround of the corrugated pipe using the CLSM backfills was smaller than those in the other cases, and the absolute value was almost zero. Judging from the small-scaled model test and FEM analysis, the use of CLSM as backfill materials should be one of the best choices reducing failure of the underground pipes.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.27 no.2
• /
• pp.5-12
• /
• 2019

The study is carried out to survey the proper management and to propose an eco - friendly separation system through efficient screening and resource recovery of excavated materials containing waste from various excavating fields such as reconstruction of landfill sites for reuse, reclamation of unsanitary landfill and residential land development of waste dumping sites. The current status and screening process and analytical characteristics of the excavated materials containing waste were reviewed. Through the analysis of the samples such as separated combustibles, recyclable soils and residues collected from the on-site visits we were able to understand the characteristics of separated materials and excavated materials containing waste such as calorific value, elementary composition, TOC, foreign material content and LOI. It has been found that elimination of the moisture of excavations, removal of attached soil from the surfaces of the excavated combustibles and the quantitative supply method of the input devices are the main operating factors as essential factors for the optimal separation of excavated materials containing waste. For efficient management and recycling of excavated materials containing, it is necessary to set criteria of ash content in separated combustibles and criteria organic matter content in separated soils.

• Journal of the Korean association of regional geographers
• /
• v.3 no.1
• /
• pp.63-80
• /
• 1997

This study attempts to establish the criteria of site selection for establishing solid waste disposal facility, to determine optimal solid waste disposal sites with the criteria, and to examine the suitability of the selected sites. The Multi-Criteria Evaluation(MCE) module in Idrisi is used to determine optimal sites for solid waste disposal. The MCE combines the information from several criteria in interval and/or ratio scale to form a single index of evaluation without leveling down the data scale into ordinal scale. The summary of this study is as follows: First, the considerable criteria are selected through reviewing the literature and the availability of data: namely, percent of slope, fault lines, bedrock characteristics, major residential areas, reservoirs of water supply, rivers, inundated area, roads, and tourist resorts. Second, the criteria maps of nine factors have been developed. Each factor map is standardized and multiplies by its weight, and then the results are summed. After all of the factors have been incorporated, the resulting suitability map is multiplied by each of the constraint in turn to "zero out" unsuitable area. The unsuitable areas are discovered in urban district and its adjacencies, and mountain region as well as river, roads, resort area and their adjacency districts. Third, the potential sites for establishing waste disposal facilities are twenty five districts in Youngyang-gun. Five districts are located in Subi-myun Sinam-ri, nine districts in Chunggi-myun Haehwa-ri and Moojin-ri, and eleven districts in Sukbo-myun Posan-ri. The first highest score of suitability for waste disposal sites is shown at number eleven district in Chunggi-myun Moojin-ri and the second highest one is discovered at number twenty one district in Sukbo-myun Posan-ri that is followed by number nine district in Chunggi-myun Haehwa-ri, number seventeen and twenty three in Sukbo-myun Posan-ri, and number two in Subi-myun Sinam-ri. The first lowest score is found in number six district in Chunggi-myun Haehwa-ri, and the second lowest one is number five district in Subi-myun Sinam-ri. Finally, the Geographic Information System (GIS) helps to select optimal sites with more objectively and to minimize conflict in the determination of waste disposal sites. It is important to present several potential sites with objective criteria for establishing waste disposal facilities and to discover characteristics of each potential site as a result of that final sites of waste disposal are determined through considering thought of residents. This study has a limitation of criteria as a result of the restriction of availability of data such as underground water, soil texture and mineralogy, and thought of residents. To improve selection of optimal sites for a waste disposal facility, more wide rage of spatial and non-spatial data base should be constructed.

• Journal of Environmental Policy
• /
• v.11 no.3
• /
• pp.25-47
• /
• 2012

This research is to suggest an ecological management methods by classification of biotope type and its mapping for Tricholoma matsutake. The target area was construction site of the East Hongchun - Yangyang Highway (Yangyang section) where massive production of Tricholoma matsutakes is in place. Specifically, the 700 m long range of area around the road route, Yangyang section, which is over a total area of $19,79km^2$. The flow of this research was as follows: first studied were the characteristics of the Yangyang Tricholoma matsutakes; second, reviews on previous studies on Tricholoma matsutakes; third, the formulation of standards and processes of biotope type considering Tricholoma matsutake production; and fourth, mapping of biotope considering the production area of Tricholoma matsutake. In 24.77% of the region, slope angle measured $30{\sim}40^{\circ}C$, which is suitable for Tricholoma matsutake production. Also, 17.44% of the region had southward vegetation structures, and as for the Pinus densiflora; 26.00% had average receipts; the tree ages was $38{\pm}8.34$ years; and the average density of canopy layer was $9.55{\pm}4.89/100m^2$. The soil acidity (pH) values of 5.0 to 5.6(47.96%) > 5.6 to 7.0(42.90%) > 4.0 to 5.0(9.14%) were slightly high for Tricholoma matsutake growth; but 57.10% of the area had a soil pH of 4.0-5.6. The organic horizon (A0 layer) was $3.39{\pm}2.14cm$, and the mean depths were 4-6cm(78.03%) > 0-2cm(18.10%) > 2-4cm(3.87%). Based on the results of previous studies and field researches on the presence of vegetation (the pine dominance ratio), the topographic structure (the terrain characteristics and slopes), the receipt, the soil structure (the soil acidity and the organic layers interposed between the depths), and the vegetation density, six clusters based on the identified types of biotopes are produced in this paper. Area of distribution according to the type of biotope was Tricholoma matsutake of the potential-production (II) biotope (32.86%) > Tricholoma matsutake of the inadequate-production biotope (22.17%) > Tricholoma matsutake of the adequate (II)-production biotope (17.79%) > Tricholoma matsutake of the adequate (I)-production biotope (14.86%) > Tricholoma matsutake of the potential-production (I) biotope (9.77%) > Tricholoma matsutake of the produced biotope (2.55%).

• Geotechnical Engineering
• /
• v.13 no.5
• /
• pp.89-100
• /
• 1997

It is very improtant to evaluate the reliable nonlinear deformational characteristics of soils not only in the analysis of geotechnical structures under working stress conditions but also for the soil dynamic problems. Field testings such as crosshole and pressuremeter tests can be used to determine the modulus of soils under in-situ conditions, but it is not possible to determine the modulus over the entire strain amplitude range. Laboratory methods such as resonant column 1 torsional shear test can be used to determine the modulus over the whole strain amplitude range, but it is very difficult to obtain the representative undisturbed samples on the sixte. For the reliable evaluation of nonlinear deformation characteristics of soils on a typical site, small strain modulus obtained from field testy and nomalized modulus reduction curve determined by laboratory bests need to be combined. In this paper, laboratory and Held testy were performed at a sixte which consisted of granite wearthered residual boils to evaluate the nonlinear deformational characteristics of coils such as the effects of strain amplitude, loading frequency, confining pressure and sample disturbance. It has been shorn that when the effects of these factors are properly taken into account, the stiffness values evaluated by various field and labrotary tests are comparable to each other fairly well. Finally, the procedure to evaluate the nonlinear deformstional characteristics of the sixte was proposed.

• Journal of Korean Society of Forest Science
• /
• v.102 no.1
• /
• pp.113-121
• /
• 2013

It has been known that edges of forest fire areas play significant roles in post-fire change of forest ecosystem and recovery process. The purpose of this study was to analyze the relationships between edge formation of burned forests and landscape characteristics with consideration on spatial autocorrelation. Samcheok fire site burned in 2000 was selected as the study area. Seven hundred fifty three of 500 $m^2$ grid cells were generated for measuring landscape characteristics. This study used the topographic variables including slop, elevation, topographic wetness index, solar radiation index and proportions of fuel and land use types. In delineating landscape characteristics correlation analysis with modified t-test were performed for exploring the relationships between edge formation and landscape characteristics. The results indicated that edge formation of burned forests was positively correlated with most variables including TWI, SRI, water, paddy, developed, farm, grass, bare soil, and negatively related with elevation, slope and all fuel types. Especially TWI (r=0.437) showed a strong positive correlation with edge formation. According to the results, edge of burned forests were likely formed when proportions of heterogeneous land use types were high with mild slope and low elevation.

• Korean Journal of Environment and Ecology
• /
• v.36 no.4
• /
• pp.402-412
• /
• 2022

This study investigated each forest's stand characteristics and the NVOCs emission characteristics for Quercus acuta, Castanopsis sieboldii, Dendropanax trifidus, Camellia Japonica which are major warm temperate evergreen broad-leaved species, and Pinus thunbergii. Data were collected from May 2019 to January 2020. The seasonal temperature and humidity of each research site indicated the typical climatic characteristics of Korea, which are hot and humid in summer and cold and dry in winter. Also, the atmospheric pressure was generally high in winter and higher in autumn and winter than in spring and summer. Overall, the total volume of NVOCs (Natural Volatile Organic Compounds) from the five research sites was the highest in the summer. The concentration of TNVOCs was relatively high in the Dendropanax trifidus forest in spring and winter, the Castanopsis sieboldii forest in the autumn, and the Quercus acuta forest in the summer. According to the results of this study, it was confirmed that the concentrations of NVOCs emission of warm temperate evergreen broad-leaved species such as Quercus acuta, Castanopsis sieboldii, Dendropanax trifidus and Camellia Japonica were not lower but rather higher than Pinus thunbergii. The correlation was positive (+) between NVOCs emission and temperature (r=0.590, P=0.000) or humidity (r=0.655, P=0.000), whereas it was negative (-) between NVOCs emission and atmospheric pressure (r=-0.384, P=0.000) or wind speed (r=-0.263, P=0.018). Among the micrometeological factors, humidity (β=0.507, P=0.000) was found to have the greatest effect on NVOC emission, followed by temperature, atmospheric pressure, and wind speed.

• Korean Journal of Environment and Ecology
• /
• v.29 no.5
• /
• pp.703-709
• /
• 2015

A breeding pair of the Black-faced Spoonbill Platalea minor was firstly recorded on Chilsando Islands, Younggwang, Jeollanamdo Province in 1991. Since the mid 2000s, breeding population on the breeding sites has gradually increased. This study was conducted to identify breeding status and nest site characteristics of the species from May to August, 2013 on Chilsando Islands. We recorded number of nests, length and width of the nest base, slope around the nests, nest materials, distances from the nearest nest, presence of nest cover and nesting area. In 2013 breeding season, 25 of 49 nests produced at least one successful fledging. A total of 55 youngs were successfully fledged and number of fledging per nest was 2.20 individuals. Nesting area was $77.8m^2$ and $93.4m^2$ for Sansando and Yuksando Islet, respectively. Soil and soil mixed with tree root were preferred for substrate of nest base over rock and Brassica napus was dominantly selected as nest materials by Black-faced Spoonbills. Nest characteristics of 22 nests in Sasando and Yuksando Islet varied $49.59{\pm}6.53cm$(mean${\pm}$SD) for length of nest base, $41.00{\pm}5.82cm$ for width of nest base, $20.85{\pm}9.96^{\circ}$ for slope above the nest, $34.09{\pm}17.75^{\circ}$ for slope below the nest and $130.82{\pm}84.17cm$ for distances from the nearest nest. Fifteen pairs (68.2%) occupied where nest cover existed. Nest cover were located in front of the nest for 5 pairs, back of the nest for 9 pairs and both front and back of the nest for 1 pair.