• Journal of the Korean Wood Science and Technology
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• v.34 no.5
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• pp.42-51
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• 2006

The this study, the effect of rice husk flour (RHF) as scavenger on formaldehyde emission rate and formaldehyde content from urea-formaldehyde (UF) resin bonded RHF content wood particleboards (PB). Two type of particle size ($30{\mu}m$ and $300{\mu}m$) of RHF was premixed with the UF resin at 5% and 15% by weight. The performance of UF resins is greatly influenced by the curing characteristics in their curing processing. The curing behavior was monitored activation energy ($E_a$) by DSC and pH variation according to RHF contents. PB with dimensions of $27cm{\times}27cm{\times}0.7cm$ was prepared at a specific gravity of 0.75 using $E_1$ and $E_2$ class UF resins. Formaldehyde emission and formaldehyde content from RHF filled PB bonded with UF resin was measured by 24 h desiccator and perforator method, respectively. RHF causes an increased pH of UF resin. $E_a$ of the modified UF resin decreased independently of RHF particle size. As the pH and the $E_a$ variation of the UF resin containing RHF increased, the amount of formaldehyde content decreased. The formaldehyde emission and formaldehyde content levels of the PB bonded with 15 wt% of $30{\mu}m$ RHF and $E_2$ type UF resin were low and satisfied grade $E_1$, as measured by 24 h desiccator and perforator method. The result of a comparison between 24 h desiccator and perforator test using PB showed that the linear regression analyses show a good correlation between the results for the 24 h desiccator and the perforator tests. The linear regression of a correlation between the desiccator and the perforator was Y=4.842X-0.064 ($R^2=0.989$). RHF was effective at reducing formaldehyde emission and formaldehyde content in urea-formaldehyde adhesives when used as scavenger.

• Korean Journal of Environment and Ecology
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• v.33 no.6
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• pp.734-747
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• 2019

This study surveyed the visitors to the Seoseokdae Peak of the Mudeungsan National Park, to analyze the factors that affected user behavior, perception of the National Park, and satisfaction with the visit and establish the strategy for the management of the Mudeungsan National Park. The analysis result showed that Gwangju residents (78.1%) accounted for the majority of the visitors to the Seoseokdae Peak and that the Mudeungsan National Park showed the attributes of both mountain type and suburb type. Most visitors (91.2%) perceived that columnar joints, including the Seoseokdae Peak, possessed the largest resource value in the Mudeungsan National Park, and the visitors showed concern over the potential damage to vegetation in the Seoseokdae Peak as the result of the overcrowded visitors. Over half of the visitors showed a positive response to the measures like partially restricted access or detour of mountain path to preserve and restore the Seoseokdae Peak. The total visitors and the regional visitors (residents of Gwangju, Damyang, and Hwasun), indicated that the facility management aimed at facilitating visitor experience affected the most on the satisfaction with park management. Moreover, the regional visitors answered that the visit management to control disorder and overcrowding would increase satisfaction. The result of the importance-satisfaction analysis showed a difference between the total visitors and the regional visitors in needed improvements as the total visitors believed that "amenities and information facilities" should be improved while the regional visitors believed that the focus should be on the "prevention of illegal and disorderly behaviors" and the "amenities and information facilities."

• Journal of Wetlands Research
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• v.19 no.1
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• pp.144-154
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• 2017

The riparian vegetation is one of corridor type ecosystems, an ecotone and able to improve the ecological soundness by structural and functional link. And they act as habitats, sources and sinks of species, conduits, filters and barriers. This study was carried out to develop the vegetation model for the fluctuation areas of lake reservoirs consider of hydrologic and soil environments according to the vegetation structure of the reference ecosystem. To develop the case study, 2 sites within 10degree slope of the Daecheong Lake were selected. The riparian vegetation models were built by the results of GIS analysis, remote satellite analysis, field survey results, consider of water level, flooded frequency, soil and topographic index, land cover or land use etc. 1) study area varied from FWL to -5m of NFWL, 2) slope 10% below, 3) vegetations flooded below 100days yearly are Salix koreensis, Salix chaenomeloides, Salix gracilistyla, 4)land cover type classified wildlife grassland, abandoned paddy field, cropland according to landuse (or landcover), 5)finally model was constructed as ecological landscape forest. The model designs were suggested by 2 types in Daecheong lake reservoir. The model for the riparian vegetation corridors could be the basic and useful data to improve the ecological and landscape properties.

• Journal of Korea Water Resources Association
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• v.49 no.5
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• pp.373-380
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• 2016

The NRCS-CN (Natural Resources Conservation Service-Curve Number) method has been practically applied for estimating the effective precipitation. However, there are no criteria which reflect the geographic characteristics of Korea having more than 70% of mountainous and rice paddy areas, leading to significant errors in runoff calculation. Thus, it is required to estimate the runoff curve number considered Korea land use classification, however there are practical difficulties to conduct the accurate research and experimentation. In this study, after selecting target areas (urban, agriculture, forest), we performed the runoff analysis to redetermine CN values for the selected basins. To do this, curve numbers for soil type A were estimated using genetic algorithm, and then curve numbers for soil type (B, C, D) were estimated using CN aligner equation. Comparing the initial curve numbers with the estimated curve numbers, it was observed that the slightly differences at Chunwang(0), Choonyang(-1), Janggi(-3). Through the above process, this study proposed new curve numbers to reflect observed rainfall-runoff.

• Journal of the Korean Association of Geographic Information Studies
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• v.10 no.4
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• pp.122-131
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• 2007

This study estimates how soil loss in a basin has been occurred according to the change of land cover, and analyzes which type of land cover has the largest soil loss by classifying the land-cover type into each area and a whole basin. Musimcheon, the second branch stream of GeumGang, is chosen as a research area. The result of analysis shows that the average soil loss occurs most largely in a crop land and a paddy field. The yearly soil loss of watershed estimates approximately 14,000 ton/yr in case of using 100-year-frequency rainfall data. A forest area, which takes the largest area in watershed, shows the soil loss occurs approximately 1,000ton/yr. A crop field shows that soil loss increased most largely 4,900 ton/yr (34.6%) in 1985 to 8,100 ton/yr (56.1%) in 2000. The change of land cover in a crop land increased 8% to 14%, and this change influences on the increase of soil loss. As a result of analyzing the area over $200ton/km^2/yr$, the soil loss in a crop field accounts for 74% to 96%.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.15 no.3
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• pp.45-54
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• 2012

This study intended to analyze growth condition of each object by protected tree's ground for 45 places registered to Pyeongtaek protected tree list in locational characteristics, conduct exchange analysis for impediment extent rate in crown area and tree type to the result and suggest the measures to manage artificial impediment which is an effect on protected tree condition. In this study, the tree whose area of impediment for crown area is less than 21% is tree condition of grade 1~2, less than 21~50% is grade 2~3 and more than 50% is grade 3~5. The more impediment is, the more inconvenience causes on growth and development. So, it verified that the area rate must maintain less than 21% for the root system management of protected tree. For the standard of managing artificial impediment which is an effect on the tree condition of protected trees, the below matters intend to be suggested. The first, the impediment in crown area should be less than 21%. But, if there is not artificial impediment out of crown area, the rate of impediment area is considered to increase somewhat. The second, growth space of protected tree should be maintained by crown area at least and impediment should be established out of the crown area. The third, during the national project and land development, surroundings of protected tree must be applied as park, resting place, etc. and the establishment area of impediment (artificial impediment and natural impediment) in crown area must be limited. The forth, publicity for regional people (especially, land owner) is necessary for the protection of natural inheritance and the value of dependence on local government and village which are the subject of management must be announced widely through the internet media, etc, so its importance must be recognized. The fifth, the matters related to protected tree management must be able to limit artificial damage which is for surroundings of protected tree through the mutual connection among the local governments; construction, civil engineering, architecture, water and sewage, agriculture and forest and others. Also, following studies on the effects of kinds, thickness, etc. of impediment around the protected tree on trees should be continued.

• Economic and Environmental Geology
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• v.37 no.2
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• pp.207-223
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• 2004

The purpose of this study is to reveal spatial relationships between landslide and geospatial data set, to map the landslide susceptibility using the relationship and to verify the landslide susceptibility using the landslide occurrence data in Boun area in 1998. Landslide locations were detected from aerial photography and field survey, and then topography, soil, forest, and land cover data set were constructed as a spatial database using GIS. Various spatial parameters were used as the landslide occurrence factors. They are slope, aspect, curvature and type of topography, texture, material, drainage and effective thickness of soil. type, age, diameter and density of wood, lithology, distance from lineament and land cover. To calculate the relationship between landslides and geospatial database, Bayesian probability methods, weight of evidence. were applied and the contrast value that is >$W^{+}$->$W^{-}$ were calculated. The landslide susceptibility index was calculated by summation of the contrast value and the landslide susceptibility maps were generated using the index. The landslide susceptibility map can be used to reduce associated hazards, and to plan land cover and construction.

• Korean Journal of Plant Taxonomy
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• v.41 no.4
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• pp.345-352
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• 2011

The morphological characters of Scrophularia kakudensis Franch. and its relatives were examined. The major features of S. kakudensis were determined to resolve the taxonomic confusion with the closely related taxa of S. kakudensis var. microphylla, S. pilosa and S. cephalantha. S. kakudensis is characterized by its flowering in Jul. to Sep., the node numbers on a stem, the size of the leaves, the development of inflorescences and the presence of glandular trichomes on its stems and leaves. S. cephalantha is distinct from S. kakudensis by the earlier flowering season, fewer node numbers on a stem, and fewer numbers of flowers on shorter rachis. Smaller sizes of S. kakudensis var. microphylla, considered to be a problematic character previously, are stable and distinctive from other taxa in the natural habitats of the multiple populations investigated in the study. Therefore, the taxon should remain as a variety of S. kakudensis. An examination of the diagnostic characteristics of S. pilosa, such as its inflorescence type and the presence of a stem with pubescence, does not provide sufficient distinction from S. kakudensis. A type specimen and habitat survey also support the merging of the two taxa. S. pilosa should be treated as a synonym of S. kakudensis, because it is considered to be a misidentification of S. kakudensis.

• Korean Journal of Plant Taxonomy
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• v.38 no.4
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• pp.573-582
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• 2008

We report a newly found natural habitat of Abeliophyllum distichum in mountainous slope range of Yeongdong-gun, Chungbuk Province. Abeliophyllum distichum Nakai is one of the Korean monotypic endemic species. Natural growth habitats of this species have been recorded from seven sites up to now, and all of the natural habitats are located in middle (Chungbuk Prov.) and middle west (Jeonbuk Prov.) parts of South Korea. Among the previously recorded seven natural habitats, six sites have been designated as Korean national monuments and protected with in situ conservation. New natural habitat of A. distichum is located on northwest slope of stiff hillock area beside the small stream, Seolgye-ri, Yeongdong-eup, Yeongdong-gun, Chungbuk Province. Total growing area is nearly $3,000 m^2$. It is 10-25 cm in soil depth and pH 5.0-6.5 in soil acidity in that area. And many of A. distichum are clustered with 2-5 individuals extended by stoloniferous asexual reproduction. And the total numbers of A. distichum are about 700 individuals with only typical white flowers, and the ratio between pin type and thrum type is 37% and 63%, respectively. The huge population of A. distichum is growing with Quercus mongolica-Fraxinus rhynchophylla association in a mixed forest, and it shows high affinity with Stephanandra incisa, Ligustrum obtusifolium, Euonymus alatus for. ciliatodentatus, and Smilax sieboldi.

• Journal of the Korean Institute of Landscape Architecture
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• v.17 no.3
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• pp.21-34
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• 1990

Trail and campground deteriorations and their environmental changes of soil and vegetation were studied in Tonghwa -Sa district of Mt. Palgong Natural Park through 1988 into 1989. The results are summarized as follows : 1. The bare width of trail as one of the trail condition factor was significantly greater on the more heavily used trail. Deterioration types of trail which had higher frequency for a total of 45 observations were rock exposure(42%), trail deepening(40%) and root exposure(18%) in the high order. And also sound type on which the trail was not deteriorated at all amounted to 33% of all observations. 2. Ecological changes of soil and vegatation of trailsides were not found at a uniform tendency except that soil hardness was slightly decreased from trail edge to the forest, but they could be grouped by the type of user\`s behavior and site conditions. Use impacts on the natural environment of trailside in Mt. Palgong are still far from the severe harmulness. 3. Worse damages to compground condition were appeared in Bawi-gol than Susu-gol campsite. Types of mechanically damaged trees were tree with exposed root(63% ), scared tree(43% ), mutilated tree(30 % ) and felled tree in highly frequent order. And diameter increments of trees in campsites were oppressed by the campers. 4. Tree damage types and their frequencies could be basic as a means of which grasp the bounds of user's impacts. User's disturbance on campsite extended to the distance of 70∼90m from the core of campsite at Pawi-gol and 20∼30m at Susu-gol respectively. As the tolerant trees to use impact, Lespedeza maximowiczii, Rhus trichocarpa, Acer palmatum, Rubus crataegifolius and Celastrus orbiculatus were considered.