• Journal of Korean Society of societal Security
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• v.1 no.1
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• pp.45-51
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• 2008

The purpose of this study is to suggest some effective ways to implement the regeneration projects for the zones vulnerable to natural disasters which have been delayed due to shortage of the financial resources, and thereby complete the disaster prevention projects as early as possible and thus secure the financial resources for the projects continuously. For this purpose, the researcher reviewed the statutory grounds and designation procedures or the zones vulnerable to natural disasters, and thereupon, examined and analyzed the regeneration projects being implemented in Gyeonggi-do in view of contents by zone, history of damages, annual investment plans and financial resources for investments. In addition, the researcher examined the criteria for reserve of the disaster management fund and its uses and investigated the fund sources and expenditures and thereby, addressed the problems of the statutory reserve and suggested their solutions. All in all, the researcher suggested that the disaster management fund should be invested in regeneration projects for the zones vulnerable to natural disasters in order to remove the disaster risks earlier and that the uses of the fund should be adequately deregulated with a reserve fund ceiling system to secure the financial resources for the disaster prevention projects continuously.

• Journal of Forest and Environmental Science
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• v.40 no.3
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• pp.210-226
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• 2024

Old-growth mixed-conifer forests in Bhutan are characterized by remarkable tree species compositional heterogeneity. However, our knowledge of tree species assemblages and their structural attributes in these forests has been limited. Therefore, forest classification has been reliant on a single dominant species. This study aimed to distinguish tree species assemblages in an old-growth mixed conifer forest in Western Bhutan and to describe their natural compositional and stand structural characteristics. Furthermore, the regeneration status of species was investigated and the quantity and quality of accumulated coarse woody debris were assessed. Ninety simple random sampling plots were surveyed in the study site between 3,000 and 3,600 meters above sea level. Tree, standing deadwood, regeneration, and coarse woody debris data were collected. Seven tree species assemblages were distinguished by Hierarchical Cluster Analysis and Indicator Species Analysis, representing five previously undescribed tree species associations with unique set of consistent species. Principal Component Analysis revealed two transitional pathways of species dominance along an altitudinal gradient, highly determined by relative topographic position. The level of stand stratification varied within a very wide range, corresponding to physiognomic composition. Rotated-sigmoid and negative exponential diameter distributions were formed by overstorey species with modal, and understorey species with negative exponential distribution. Overstorey dominant species showed extreme nurse log dependence during regeneration, which supports the formation of their modal distribution by an early natural selection process. This allows the coexistence of overstorey and understorey dominant species, increasing the sensitivity of these primary ecosystems to forest management.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.47 no.5
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• pp.335-340
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• 2002

To evaluate the efficiency of anther floating culture according to the maturing group, the varietal difference and classification of fifty varieties was conducted in N6 liquid medium containing 1mg $l^{-1}$ NAA, 0.25 mg $l^{-1}$ kinetin. The efficiency of callus induction was widely ranged from 0 to 113.4%, but the mean callus induction was not significantly different among maturing groups. The efficiency of anther floating culture showed the highest variation in early-maturing group among three maturing groups. The varieties with the best callus induction were Sambaegbyeo and Jinbuolbyeo, while the recalcitrant variety was Obongbyeo in early-maturing group. The efficiency of plant regeneration showed the highest trends in late-maturing group among three maturing groups. The fifty varieties were classified into three groups (distance=0.78) by cluster analysis based on the callus formation and plant regeneration. Group including only two varieties, Shinunbongbyeo and Sambaegbyeo had the excellent androgenic efficiency, and the medium efficiency of Group was included thirty-six varieties. Whereas twelve varieties, including three Tongil varieties were fell into the bad efficiency of Group. Especially, Tongil varieties containing Japonica rice, Obongbyeo were the recalcitrant genotypes for the anther floating culture.

• Journal of Korean Society of Forest Science
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• v.85 no.3
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• pp.524-531
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• 1996

The objective of this study was to determine the important factors affecting the early natural regeneration of Pinus densiflora S. et Z. Seed germination, survival and height growth of the pine seedlings were examined at four experimental plots of P. densiflora forests including forest roadside. Plots I and III were thinned in 1992, plot II was treated with hexazinone in 1993 after seed tree method was applied in 1982 and 1989. Seedlings emerged after thinning and the rate of their emergence depended on forest floor conditions. Seedling survival was related with light conditions, herbaceous vegetation, and degrees of rainfall. More seedlings emerged in forest hauling roads than within the forest because soil scarification due to logging provided better conditions for seed germination and seedling growth. Seed supply was enough, but germination rate was very low in the forest compared with that in the greenhouse because micro-environments such as organic layer and herbaceous plant acted as limiting factors. Weed control was needed for 4 to 5 years until seedlings grew upto about 50cm in height which was similar to that of herbaceous plants. But 10-40% coverage of herbaceous vegetation was needed to protect small seedlings from heavy rain. Forest works such as thinning and logging, over 40% of light were important factors to help the pine regeneration. However, over 70% coverage of herbaceous vegetation, and heavy rain inhibited rather survival and growth of pine seedlings.

• Korean Journal of Environment and Ecology
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• v.17 no.2
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• pp.105-111
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• 2003

To develope reforestation methods for enviromentally sound and ecological forest management, Fraxinus rhynchophylla stand structure and radial growth of the trees were invstigated and compared by study sites. Plantation forest studied on Fraxinus rhynchophylla, was located at Jawoon-ni Nae-myeun, Hongcheon-gun and natural forest studied on Fraxinus rhynchophylla, was located at Jangjeon-ni Jinbu-myeun, Pyeungchang-gun. In 7,8 years after planting, differences of annual diameter increment among three stand origins were significant. The highest mean annual diameter increments of F. rhynchophylla, 4.60 mm/year was measured in sprouting trees, and followed by natural seedlings 4.59 mm/year. The lowest values, 4.18mm/year did in planting trees. Early radial growth of planting F. rhynchophylla was measured lower than that of sprouting or natural seedlings. These facts mean that planting F. rhynchophylla is not proper regeneration methods. Other regeneration methods of F. rhynchophylla forest, by sproutings, direct seeding and natural seeding, might be researched and recommended.

• Korean Journal of Environment and Ecology
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• v.17 no.4
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• pp.309-315
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• 2004

To estimate planting results of deciduous broad-leaved species, forest structure and radial growth of the trees were investigated and compared by species and studied sites. Plantation forest studied on Juglans mandshurica, was located at Jawoon-ni Nae-myeun, Hongcheon-gun and natural forest studied on Juglans mandshurica, was located at Jangjeon-ni Jinbu-myeun, Pyeungchang-gun. In 9 years after planting, differences of annual diameter increment among three stand origins were significant. The highest mean annual diameter increments of J. mandshurica, 7.31mm/year was measured in natural seedlings, and followed by sprouting trees 6.93mm/year. The lowest values, 5.28mm/year did in planting trees. Early radial growth of planting J. mandshurica was measured lower than that of sprouting or natural seedlings. These facts means that planting J. mandshurica is not proper regeneration methods. Other regeneration methods of J mondshurica forest, by sproutings, direct seeding and natural seeding, might be researched and recommended.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.45 no.1
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• pp.34-42
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• 2019

Objectives: Various bone graft substitute materials are used to enhance bone regeneration in the maxillofacial skeleton. In the recent past, synthetic graft materials have been produced using various synthetic and natural calcium precursors. Very recently, eggshell-derived hydroxyapatite (EHA) has been evaluated as a synthetic bone graft substitute. To assess bone regeneration using EHA in cystic and/or apicectomy defects of the jaws through clinical and radiographic evaluations. Materials and Methods: A total of 20 patients were enrolled in the study protocol (CTRI/2014/12/005340) and were followed up at 4, 8, 12, and 24 weeks to assess the amount of osseous fill through digital radiographs/cone-beam computed tomography along with clinical parameters and complications. Wilcoxon matched pairs test, means, percentages and standard deviations were used for the statistical analysis. Results: The sizes of the lesions in the study ranged from 1 to 4 cm and involved one to four teeth. The study showed significant changes in the formation of bone, the merging of material and the surgical site margins from the first week to the first month in all patients (age range, 15-50 years) irrespective of the size of the lesions and the number of teeth involved. Bone formation was statistically significant from the fourth to the eighth week, and the trabecular pattern was observed by the end of 12 weeks with uneventful wound healing. Conclusion: EHA showed enhancement of bone regeneration, and healing was complete by the end of 12 weeks with a trabecular pattern in all patients irrespective of the size of the lesion involved. The study showed enhancement of bone regeneration in the early bone formative stage within 12 weeks after grafting. EHA is cost effective and production is environment friendly with no disease transfer risks. Thus, natural bioceramics will play an important role in the reduction of costs involved in grafting and reconstruction.

• Journal of Periodontal and Implant Science
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• v.29 no.2
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• pp.297-313
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• 1999

The ultimate goal of periodontal treatment is the regeneration of periodontal tissues which have been lost due to periodontal disease. Recently, many natural medicines have been studied for their potential of anti-bacterial, anti-inflammatory and regenerative effects in periodontal tissues. Safflower seeds have been traditionally used as a drug for treatment of fracture and blood stasis in oriental medicine. The objective of the present study is to examine the biologic effects of safflower seeds extract on bone formation and regeneration of rat calvarial defects. The calvarial defects were made with 8mm trephine bur and extract of safflower seeds were placed directly at these defects. 24 rats were divided into control and experimental groups, and each group was sacrificed at 1 week, 4 weeks and 8 weeks. To study a histopathology related to bone regeneration, Goldner's Masson Trichrome stain and histomorphologic measuring was done at each weeks. In the early phase of bone healing, less inflammatory infiltration and capillary proliferation was found in experimental group compared to control. Dense bony tissues and matured bone structures in defect areas were found in experimental groups. And area of new bone formation was significantly increased at 8 weeks in experimental group. These results indicate that direct local application of safflower seeds extract reduces the early inflammatory response and promotes the regeneration of new bone in calvarial defects of rats.

• Journal of Korean Society of Forest Science
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• v.112 no.3
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• pp.280-289
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• 2023

Diverse native tree species are distributed in Korean forests; however, information on their regeneration strategies is limited. This study analyzed seed rain from 2011 to 2013, seedling emergence, seedling survival, lifespan distribution, and the relationship between seedling mortality and herbaceous vegetation for 3 years, from 2012 to 2014, to understand the natural regeneration and early survival characteristics of Fraxinus rhynchophylla Hance in natural broad-leaved forests. Seed rain and emerged seedling density significantly differed among the years (p < .05). An increase in seed rain was followed by an increase in seedling emergence in the following year. Seed rain in 2013 and seedling emergence in 2014 showed a significant correlation (p < .05), confirming the trait of F. rhynchophylla seeds that germinate in the following year after seed production. Seedlings emerged in late spring and early summer. Of the seedlings, 78% emerged in the early summer of 2014. Most seedlings died immediately after emergence. Of the seedlings that emerged in August 2012, 56% died within 2 months, and 38% of those that emerged in July 2014 died within 1 month. Shade and competition against ground vegetation chiefly affected the seedling survival of F. rhynchophylla. Fraxinus rhynchophylla showed mast seeding, with a large number of seed production in a particular year. A surge of seedling emergence followed in the early summer of the next year. However, most seedlings died in the same year of emergence. Fraxinus rhynchophylla has a high seedling mortality, but mast seeding and the resulting high seedling emergence produce a few survived seedlings, enabling the continuation of the F. rhynchophylla population. Efforts and research on the natural regeneration of native tree species are required to effectively manage natural forests in Korea.

• Journal of Ecology and Environment
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• v.41 no.6
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• pp.152-164
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• 2017

Background: Natural regeneration of seedlings as well as saplings of Korean fir has been significantly impacted by the browsing from the early stages of their development, potentially, by roe deer for the last two to three decades at the study site since late 1980s. This study was carried out to investigate current status of the disturbance in the seedling development of Korean fir (Abies koreana) on Mt. Hallasan, Jeju Island, Korea. Methods: Field survey was carried out during June and August in 2016 to measure the characteristics of study site and understory vegetation by applying systematic sampling to 125 plots of $5m{\times}5m$ quadrat located on eastern slope of the mountain. Correlation and regression analyses were applied to the variables quantified from the data sets using the SAS software. Results: No saplings with their diameters at breast heights smaller than 5.0 cm were found at the study site indicating the serious disturbance in the natural regeneration of Korean fir at the study site. No seedlings with their heights taller than 36.0 cm were found at the study site indicating even more serious disturbance during earlier stage of the natural regeneration of Korean fir at the study site. A total of 616 individuals of the seedlings of Korean fir were found at 54 out of 125 sampling plots. One hundred thirty-eight seedlings (22.4%) out of 616 individual seedlings have the vestiges for being grazed, potentially, by roe deer. Conclusions: Due considerations should be given to the effects of browsing of the seedlings by roe deer to promote the natural regeneration of Korean fir, ultimately to restore Korean fir. It is needed for the managers of the forest to install fences around the forest area. Exclosure experiments as well as enclosure experiments of different densities of browsing should be carried out. In addition, treatment with different densities of Jeju dwarf bamboo should also be included in the experiment on Mt. Hallasan National Park, Jeju Island, Korea.