• Journal of Forest and Environmental Science
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• v.34 no.2
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• pp.119-125
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• 2018

The tropical forests in developing countries are faced with the problem of illegal exploitation of trees. However, dearth of empirical means of expressing the dimensions, structure, quality and quantity of a removed tree has imped conviction of offenders. This study aimed at developing a model that can effectively estimate individual tree basal area (BA) from stump diameter (Ds) for Tectona grandis stands in Omo Forest Reserve, Nigeria, for timber valuation in case of illegal felling. Thirty-six $25m{\times}25m$ temporary sample plots (TSPs) were laid randomly in six age strata; 26, 23, 22, 16, 14, and 12 years specifically. BA, Ds and diameter at breast height were measured in all living T. grandis trees within the 36 TSPs. Least square method was used to convert the counted stumps into harvested stem cross-sectional areas. Six basal area models were fitted and evaluated. The BA-Ds relationship was best described by power model which gave least values of Root mean square error (0.0048), prediction error sum of squares (0.0325) and Akaike information criterion (-15391) with a high adjusted coefficient of determination (0.921). This study revealed that basal area estimation was realistic even when the only information available was stump diameter. The power model was validated using independent data obtained from additional plots and was found to be appropriate for estimating the basal area of Tectona grandis stands in Omo Forest Reserve, Nigeria.

• Korean Journal of Agricultural Science
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• v.48 no.3
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• pp.473-482
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• 2021

In this study, we attempted to estimate the degree of management of chestnut forestry households in Chungcheongnam-do and to provide information for establishing chestnut cultivation-related policies. The chestnut management standard diagnostic table consists of three major categories, namely, management base, management and sales capacity, and production technology levels, along with 19 subcategories. A survey of 309 chestnut forestry households was conducted from 2014 to 2019 in Gongju, Cheongyang, and Buyeo in Chungcheongnam-do. The average score for the 19 subcategories was 65.7 points, indicating that these areas have excellent management conditions. When the total score was higher, the output per hectare and the rate of top-grade products in the total output were also higher, indicating a significant correlation. These findings will be useful for providing consulting services to chestnut growers as they highlight the correlation between the higher scores of the indicators in the chestnut management standard diagnostic table and the management performance of the farmers. We found that the scores of the indicators for management and sale skill, such as management record and analysis, material purchase, and direct transaction with consumers, were relatively lower than those of the indicators for management base and production skill. It is assumed that the chestnut growers aging has led to negligence in recording details on incomes, expenditures, and work and lowered the willingness to make substantial profits. Therefore, it is essential to overcome these problems for profitable chestnut farming.

• Journal of Forest and Environmental Science
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• v.34 no.5
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• pp.395-404
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• 2018

Since the mass mortality of Quercus mongolica has been first reported in Gyeonggi province at 2004, the disease spread rapidly over Korean peninsula annually. Ambrosia beetle (Platypus koryoensis) was known as the insect vector of oak wilt fungus, Raffaelea quercus-mongolicae, and control methods of the disease had mainly been focused on eradication of insect vector. However, for the efficient management of the disease, combined control methods for both of the pathogenic fungus and insect vector are strongly required. As one of the efforts to suppress the pathogenic fungus, antifungal activities of Streptomyces isolated from oak forest soil were assayed in this study. Optimum culture condition for the selected isolates was also studied, As a result, Streptomyces blastmyceticus cultured in PDB (Potato Dextrose Broth) at $25^{\circ}C$ for 1 week showed the strongest antifungal activity against oak wilt fungus. Mycelial growth inhibition rates (MGIRs) of Streptomyces isolates were compared on culture media supplemented with heated and unheated culture filtrates of S. blastmyceticus. MGIRs on culture media with unheated culture filtrates were generally higher than those on culture media with heated culture filtrates. Antagonistic mechanism to get involved in the inhibition of hyphal growth and spore formation of the pathogen is due to the antifungal metabolites produced by Streptomyces. This study will provide the fundamental information in developing biocontrol agents for the environment-friendly management of oak wilt disease.

• Korean Journal of Agricultural Science
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• v.47 no.4
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• pp.727-742
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• 2020

Point cloud-based 3D maps can obtain many kinds of information for maintenance work on forest road networks. This study was conducted to compare the importance of each factor to select the factors required for the mapping of 3D forest road maps. This can be used as basic data for attribute information required to maintain forest road networks. The results of this study found that out of a total of 30 indexes extracted for mapping 3D forest roads, a total of 21 indexes related to stakeholder groups were significantly different. The importance of the index required by the civil service group was significantly higher than that of the other groups overall. In the case of the academic group, the index importance for cut slope, fill slope, and drainage facility was significantly higher. On the other hand, the index importance for the forestry cooperative and forest professional engineer group was mostly distributed between the civil servants' group and the academic group. In particular, the type of drainage system showed the highest value among the detailed indexes. Overall, drainage related factors in this survey had high coefficient values. The impact of water on forest roads was the most important part in road maintenance. In addition, the soil texture had a high value in relation to slope stability. This is thought to be because the texture of the soil affects the stability of the slope.

• Journal of the Korean Association of Geographic Information Studies
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• v.10 no.4
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• pp.22-34
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• 2007

The purpose of this study is to evaluate landscape characteristics of watersheds in the Nakdong River Basin for identifying the groups of watershed with similar landcover patterns by using Geographic Information System and statistical technique. According to the results based on the cluster analysis using cluster analysis tool in the ArcGIS 8.3 program, 22 sub-watersheds were classified into three types; "Forest watershed", "Agriculture watershed", and "Urban watershed". In the forest watershed that has the least potential of ecological disturbances by human, a forest management approach based on geographic conditions and coverage types, etc., should be developed to sustain the ecological and environmental functions of forest. For the agriculture watershed, environmental-friendly agricultural techniques should be performed in the particular enhancement of riparian buffer zone to the prevent direct inflow of soils, fertilizers, and other chemicals into the stream network. Finally, in the urban watershed, an environmental-friendly plan that may increase the ratio of pervious surface and amount of green-space to should be reserved.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.8
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• pp.370-377
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• 2018

Currently, Korea is ahead of the forest sector such as forest management, forest investigation and forest management, which is not insufficient compared with the forest advanced countries (Germany, Japan, Austria). However, there is a lack of systematic and advanced forest management plan and related research, and it is not enough to construct GIS for practical and complex analysis. Therefore, in order to perform forest analysis effectively, this study maps forest basic statistics (2010, 2015) based on GIS to map forest information. As a result, the forest area, growing stock, average growing stock, and forest rate could be produced with the maximized visual effect by detailed administrative districts, and systematic analysis of the time series changes was also possible. Forest area increased only in Goseong, Sejong, Cheolwon, Yeoncheon, Daejeon, and Seoul Guro-gu, and decreased in all other areas, while growing stock increased in most areas, Uljin, Ulleung, Seoul Nowon-gu, and Seoul Gangdong-gu. The average growing stock was found to increase in most areas excluding the four administrative districts and the forest rate was higher in 10 regions (Goseong, Yeoncheon, Gongju, Busan Dong-gu, Daegu Seo-gu, etc.) but it decreased in most regions excluding 10 regions. Based on this research, we plan to produce and analyze forest information maps for smaller administrative districts and more.

• Journal of Korean Society of Rural Planning
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• v.26 no.1
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• pp.101-112
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• 2020

Recently, public awareness regarding mountain villages' landscapes is increasing. Thus, this study aimed to provide standards for conservation, management and creation of mountain village landscape by characterizing and classifying those exist. 286 mountain villages' data were collected and 19 variables - extracted from GIS spatial information and statistic data of mountain villages, chosen as right sources according to former studies - were utilized to conduct factor and cluster analysis. As a result of the factor analysis, 7 characteristics of the mountain villages' landscapes were defined - 'Location', 'Cultivation', 'Ecology·Nature', 'Tourism', 'Residence', 'Recreation'. The K-means cluster analysis categorized the mountain villages' landscapes into four types - 'Residential', 'Touristic', 'General', 'Environmentally protected'. The classification was examined to be appropriate by field assessment, and basic guidelines of mountain village landscape management were set. The results of this study are expected to be utilized planning and implementing regarding mountain village landscape in the future.

• Journal of Environmental Science International
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• v.31 no.9
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• pp.793-801
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• 2022

This study was carried out to provide basic data for logical forest management by developing a site index curve reflecting the current growth characteristics of Cryptomeria japonica stands in Korea. The height growth model was developed using the Chapman-Richards, Schumacher, Gompertz, and Weibull algebraic difference equations, which are widely used in growth estimation, for data collected from 119 plots through the 7th National Forest Inventory and stand survey. The Chapman-Richards equation, with the highest model fit, was selected as the best equation for the height growth model, and a site index curve was developed using the guide curve method. To compare the developed site index curve with that on the yield table, paired T-tests with a significance level of 5% were performed. The results indicated that there were no significant differences between the site index curve values at all ages, and the p-value was smaller after the reference age than before. Therefore, the site index curve developed through this study reflects the characteristics of the changing growth environment of C. japonica stands and can be used in accordance with the site index curve on the current yield table. Thus, this information can be considered valuable as basic data for reasonable forest management.

• Journal of the Korean Association of Geographic Information Studies
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• v.18 no.2
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• pp.149-160
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• 2015

This study aims to estimate the forest volumes of the upper region of Nam-Han River in ecosystem zoning by forest types and age classes, and to suggest the optimal estimation method through the comparison of the standard errors according to the spatial unit. In the estimation of forest volumes, we used both of direct estimation, which uses sample plots of the target area only, and synthetic estimation, which includes sample plots of the expanded areas as well as those of the target area. As for the spatial expansion, we applied four standards for synthetic estimator: Mountainous zone, Neighbor ecosystem region, Gangwon province, and Buffer zone. The results show that average forest volume per ha, calculated by direct estimation, was $143.5m^3/ha$, while that by synthetic estimation with each standard, was estimated at $146.9m^3/ha$ by Gangwon province, $144.8m^3/ha$ by Buffer zone, $139.8m^3/ha$ by Neighbor ecosystem region, and $138.6m^3/ha$ by Mountainous zone, respectively. The standard errors of direct estimation was $1.79m^3/ha$, while those of synthetic estimation showed not a great difference among the errors. Meanwhile, considering the standard errors by forest type, the lowest was ${\pm}2.3m^3/ha$ of broad-leaved forest, followed by ${\pm}3.3m^3/ha$ of mixed forest, and ${\pm}4.8m^3/ha$ of coniferous forest.

• Journal of Cadastre & Land InformatiX
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• v.48 no.2
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• pp.21-30
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• 2018

The spatial information recently observed by various sensors and platforms has been provided by national portals through the establishment of a database over a number of time periods, with easy access to various types of information. Therefore, it is possible to analyze the changes in the national territory space according to time. This study is intend to analyze forest changes based on a case of some areas in Heongseong and Wonju using the various spatial information observed in many ways, such as aerial photographs, ortho photos, digital topographical maps, DEM and DSM. DSM created by the airborne lidar and the aerial photos was able to analyze forest change areas more effectively than DEM of topographical maps. Also, forest management and analysis could provide basic data for efficient preservation and management of forests using spatial information.