• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
• /
• 2005.05a
• /
• pp.254-259
• /
• 2005

Big fire such as mountain fire my cause the prevention of the functions of the overhead cables and insulators, which may affect the operation of the transmission lines. Therefore, in order to understand the effect of the mountain fire on the polymeric insulator for transmission lines, the author observed the deformation of the sheds of the polymeric insulators and the change of the discs of the porcelain insulators under fire, and investigated the electrical and mechanical characteristics of the insulators after the ignition test. As the result the following conclusions were obtained. First, the porcelain insulator was degraded in electrical characteristics when the insulator was subjected to the fire for approximately 5 minutes; whereas, the polymeric insulator was not degraded though there were some damage on its sheds. Second, after 20 minute exposure to the fire, the polymeric insulator lost a lot of parts of sheds, but the electrical characteristics was lowered by around 20%, but the porcelain insulators were electrically degraded by more than 80%.

• Journal of Korean Society of Forest Science
• /
• v.96 no.3
• /
• pp.269-282
• /
• 2007

The purpose of this study is to investigate the causes of the dramatic process in forest policies from July of 1972 to June of 1973. In 1972, the core forest problem calling for an immediate solution was the severe forest degradation such as a low growing stock ($11m^3/ha$) and lots of non-tree forest land corresponding to 12% of total forest land. There could have been various approaches to solve the problem at that time. By the end of 1972, the Korean government was afoot to choose the management-oriented approach to carry out reforestation as a part of forest management. In order to implement this approach, the Korean government established the Forest Development Law enforcing establishment of the Forest Management Corporation as a public organization to carry out forest management in the special development land. However, the Korean government changed the management-oriented approach into the administration-oriented approach to carry out reforestation as a part of forest greening in order to rehabilitate severe degraded forests as soon as possible in early 1973. The Forestry Administration (refer to Forest Service) was transferred from the Department of Agriculture and Forestry to the Department of Interior for the efficient rehabilitation in advance, before the 1st 10-year National Greening Project. After the organization's transfer, the government established the 1 st 10-year National Greening Project aiming to reforest one million ha from 1973 to 1982 to use activities like the national greening campaign and the administrative organization mobilization including police force. Reforestation policy as a part of forest management lost effect due to the greening-oriented approach choice. Moreover, the Government struggled to provide 20 billion won for the establishment of the Forest Management Corporation. After all, on March 5th of 1973, the management-oriented approach dropped a curtain deleting the clauses defining the establishment of the Forest Management Corporation. Park, Chung-hee who was the then president of Korea might have felt the 'time restriction' to lose no time to habilitate degraded forests. Due to his awareness, the approach regarding reforestation was changed into administration-oriented activities. The president's awareness was considered as an invisible cause at that time.

• Korean Journal of Remote Sensing
• /
• v.32 no.1
• /
• pp.1-11
• /
• 2016

Since forest is an important part of ecological system, the deforestation is one of global substantive issues. It is generally accepted that the climate change is related to the deforestation. The issue is worse in developing countries because the forest is one of important natural resources. In the case of North Korea, the deforestation is on the rise from forest reclamation for firewood collection and food production. Moreover, a secondary effect from flood intensifies the damage. Also, the political situation in North Korea presents difficulty to have in-situ measurements. It means that the accurate information of North Korea is nearly impossible to obtain. Thus, assessing the current situation of the forest in North Korea by indirect method is required. The objective of this study is to monitor the forest status of North Korea using multitemporal Landsat images, from 1980s to 2010s. Since the deforestation in North Korea is caused by local residents, we selected two study areas of high population density: Pyeongyang and Hyesan. In North Korea, most of clean Landsat images are acquired in fall season. The fall images have an advantage that we can easily distinguish agriculture areas from forest areas, also have an disadvantage that the forests cannot be easily identified because some of trees have turned red. To identify the forests exactly, we proposed a modified Normalized Difference Vegetation Index (mNDVI) value. The deforestation in Pyeongyang and Hyesan was analyzed by using mNDVI. The dimension of forest has decreased approximately 36% in Pyeongyang for 27 years and approximately 25% in Hyesan for 16 years. The results show that the forest areas in Pyeongyang and Hyesan have been steadily reduced.

• Journal of Forest and Environmental Science
• /
• v.39 no.3
• /
• pp.167-179
• /
• 2023

The extent of change in the Land use/Land cover (LULC) of Okomu National Park (ONP) and fringe communities was evaluated. High resolution Landsat imagery was used to identify the major vegetation cover/land use systems and changes around the national park and fringe communities while field visits/ground truthing, involving the collection of coordinates of the locations was carried out to ascertain the various land cover/land use types identified on the images, and the extent of change over three-time series (2000, 2010 and 2020). The change detection was analyzed using area calculation, change detection by nature and normalized difference vegetation index (NDVI). The result of the classification and analysis of the LULC Change of ONP and fringe communities revealed an alarming rate of encroachment into the protected area. All the classification features analyzed had notable changes from 2000-2020. The forest, which was the dominant LULC feature in 2000, covering about 66.19% of the area reduced drastically to 36.12% in 2020. Agricultural land increased from 6.14% in 2000 to 34.06% in 2020 while vegetation (degraded land) increased from 27.18% in 2000 to 38.89% in 2020. The magnitude of the change in ONP and surroundings showed the forest lost -247.136 km² (50.01%) to other land cover classes with annual rate change of 10%, implying that 10% of forest land was lost annually in the area for 20 years. The NDVI classification values of 2020 indicate that the increase in medium (399.62 km² ) and secondary high (210.17 km² ) vegetation classes which drastically reduced the size of the high (38.07 km² ) vegetation class. Consequent disappearance of the high forests of Okomu is inevitable if this trend of exploitation is not checked. It is pertinent to explore other forest management strategies involving community participation.

• Korean Journal of Environment and Ecology
• /
• v.34 no.6
• /
• pp.558-572
• /
• 2020

The purpose of this study was to classify the types of degraded areas of Mt. Jirisan section in Baekdudaegan and survey the actual condition of each damage type to use it as basic data for the direction of the restoration of damaged areas according to damage type based on the vegetation information of reference ecosystem. The analysis of the Mt. Jirisan section's actual degraded conditions showed that the total number of patches of degraded areas was 57, and the number of patches and size of degraded areas was higher at the low average altitude and gentle slope. Grasslands (deserted lands) and cultivated areas accounted for a high portion of the damage types, indicating that agricultural land use was a major damage factor. The survey on the conditions of 14 degraded areas showed that the types of damage were classified into the grassland, cultivated area, restoration area, logged-off land, and bare ground. The analysis of the degree of disturbance (the ratio of annual and biennial herb, urbanized index, and disturbance index) by each type showed that the simple single-layer vegetation structure mostly composed of the herbaceous and the degree of disturbance were high in the grassland and cultivated land. The double-layer vegetation structure appeared in the restoration area where the pine seedlings were planted, and the inflow of naturalized plants was especially high compared to other degraded areas due to disturbances caused by the restoration project and the nearby hiking trails. Although the inflow of naturalized plants was low because of high altitude in bare ground, the proportion of annual and biennial herb was high, indicating that all surveyed degraded areas were in early succession stages. The stand ordination by type of damage showed the restoration area on the I-axis, cultivated area, grassland, logged-off land, and bare ground in that order, indicating the arrangement by the damage type. Moreover, the stand ordination of the degraded areas and reference ecosystem based on floristic variation showed a clear difference in species composition. This study diagnosed the status of each damage type based on the reference ecosystem information according to the ecological restoration procedure and confirmed the difference in species composition between the diagnosis result and the reference ecosystem. These findings can be useful basic data for establishing the restoration goal and direction in the future.

• Journal of Korean Society of Forest Science
• /
• v.96 no.5
• /
• pp.567-571
• /
• 2007

This study was conducted to clarify the differences in breeding bird communities between deciduous forests of Gwangneung and Mt. Namsan areas from April to August 2006. Two 10ha area were selected for territory mapping of breeding bird community in both study area. The DBH distribution of trees and average foliage profiles were significantly different between study areas. Also, breeding bird communities were different. Number of breeding species and pairs, breeding density, and bird species diversity were higher in Gwangneung area than in Mt. Namsan area. When examining relationship between forest habitat structure and bird community, Number of bird species and breeding pairs belonged to hole and canopy guild were increase as the increase of coverstory coverage and number of large trees. Therefore, it is necessary to make vertical structure more various to plant bushes, and to make DBH distribution more diverse for enhancing bird species diversity in the degraded ecosystem.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.43 no.2
• /
• pp.49-56
• /
• 2011

Mulching technique is used to control the temperature and moisture content of soil by covering the ground surface. Most kinds of mulching film are made of polyethylene which is non-biodegradable synthetic polymer. Utilizing these films has been one of the main sources in soil pollution. Thus residual films under the ground should be removed after a certain period of time. Therefore, an alternative mulching material made of biodegradable functional paper is considered instead of non-biodegradable films. The mulching sheet produced from paper basis has a functionality to be naturally degraded and then recycled to the bio-materials on soil. In this study, the paper based-mulching sheet coated with biodegradable polymer was specially produced using a laboratory bar coater. Coating colors prepared by dissolving PBS/PLA in chloroform were applied to kraft paper. The mechanical strength and aging properties of this mulching sheet were investigated. The burst strength of polymer-coated paper was decreased with the increase of the PBS ratio in PBS/PLA blends, and, in particular, 30/70 blending condition led to good stability in heat-aging atmosphere for 60 days.

• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.13 no.5
• /
• pp.146-153
• /
• 2010

Urban development typically results in many species being confined to small, isolated and degraded habitat fragments. Fragment size and isolation underpin many studies of modified landscape to prevent biodiversity loss. However, habitat characteristics such as vegetation structure and edge effects are less frequently incorporated in planning. The relative influence of biogeographic (e.g. size, isolation) and vegetation parameters on assemblages is poorly understood, but critical for conservation management. In this study, the relative importance of biogeographic and vegetation parameters in explaining the diversity of forest-interior dwelling birds in forest fragments in Chungcheong Province Area. Fragment size and vegetation characteristics were consistently important predictors of bird diversity. Forestinterior bird richness was influenced by fragment size (0.437), wood age (0.332), wood diameter (0.068), and patch shape (-0.079). To preserve bird diversity of Chungcheong Province Area, it is important to consider differing responses of bird diversity to landscape change, move beyond a focus primarily on spatial attributes (size, isolation) to recognize that landscape change also has profound effects on habitat composition and quality. The result is very useful for long-term aspect of biodiversity conservation plan in regional scale.

• Journal of Forest and Environmental Science
• /
• v.39 no.2
• /
• pp.96-104
• /
• 2023

The successful restoration program requires a comprehensive understanding of variables influencing seedling efficiency. Below-ground is hypothesized to have a major impact on seedling performance of species when planted in agriculture, and degraded areas with different types of mulching. This study investigated on Sg. Terla Forest Reserve in Cameron Highlands Pahang, Malaysia. In this study randomized complete block design (RCBD) was used. The excavation method was applied to study the root system development, above, and below ground biomass distributions under different types of mulching: coconut mulching (CM), oil palm mulching (OM), plastic mulching (PM) and control (CK). The root diameter, main root length, lateral root length, root coiling, and root direction toward to sun were recorded. The results in this study indicate that mulching had significant effect on root diameter, main root length, and root distributions among treatments while for lateral root length, root: shoot ratio, dry biomass distributions, and above and below ground biomass did not showed significant effect among treatments. The highest values for root diameter, lateral root length, main root length, root distributions, dry biomass distributions and above and below ground biomass were showed in CM treatments. However 75% of root coiling was observed in seedlings between treatments.

• Korean Journal of Environment and Ecology
• /
• v.17 no.1
• /
• pp.71-82
• /
• 2003

To set out restoration plan of Evergreen Broad-Leaved Forests(EBLF), a case study was done at Wando arboretum, Sinjido and Jangdo(Island). Firstly, basic environmental survey was done and the degrade levels of EBLF was assessed. And the forest functions and restoration goal of vegetation have been established before considering and setting restoration types of vegetation and restoration techniques. Taking social demand and restoration goal etc. into consideration, the forest functions were classified into a ecosystem preservation, scenery conservation and timber production. Quercus acuta Forest, Castanopsis siebodii Forest, Persea thunbergii Forest, Cinnamomum japonicum Forest, Dendropanax morbifera Forest etc. were suggested as a restoration goal of vegetation. Restoration types of vegetation were classified into a preservation type, restoration type, reconstruction type and afforestation type. And restoration techniques were subdivided into a preservation, induction, improvement, and creation according to the degraded levels of EBLF.