• Korean Journal of Plant Taxonomy
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• v.47 no.3
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• pp.207-221
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• 2017

Thymelaeaceae in Korea includes ten species in five genera (Daphne, Diarthron, Edgeworthia, Stellera, and Wikstroemia). This study investigated the morphology of these species using herbarium specimens and fresh materials obtained during fieldwork to understand the variation level and to delineate each taxon in the family. Our comparative morphological analysis showed that the Korean taxa in Thymelaeaceae were easily distinguished based on their morphologies. It is easy to distinguish Daphne from Wikstroemia when the Korean taxa are considered. However, Daphne genkwa is morphologically similar to Wikstroemia based on the leaf arrangement, pubescence of the leaves, and the ovary shape. The results here suggest that further systematic studies of the Daphne group using more data are necessary.

• Korean Journal of Environment and Ecology
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• v.24 no.5
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• pp.547-555
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• 2010

To investigate the vegetation structure of mountain ridge from Bammeorijae to Woongseokbong, 25 plots($400m^2$) selected by random sampling method were surveyed. Three groups of Quercus mongolica - Pinus densiflora community, Q. dentata community and Q. mongolica - Q. dentata community were classified by cluster analysis. Q. dentata, Q. variabilis, Pinus densiflora, Acer pseudosieboldianum and Q. mongolica were found as mostly dominant woody plant species in the Woongseok-bong area. In the future, the importance percentage of Pinus densiflora might be eventually decreased, but those of Q. mongolica, Q. variabilis and Q. dendata might be gradually increased. There were strong positive correlations between Pinus densiflora, Zanthoxylum piperium and Lindera obtusiloba; Q. mongolica and Rhododendron mucronulatum; Styrax obassia and R. schlippenbachii; Fraxinus sieboldiana, Zanthoxylum piperium and Styrax obassia; Acer pseudosieboldianum and Fraxinus sieboldiana; Cornus controversa and Corylopsis coreana were relatively weak negative correlations between Q. dentata and Q. mongolica; Lindera erythrocarpa, Q. mongolica and Q. variabilis; Q. mongolica, Larix leptolepis and Q. variabilis; Symplocos chinensis for. pilosa and Rhododendron mucronulatum. Species diversity index(H') of investigated groups was ranged from 0.09832 to 1.1102.

• Korean Journal of Plant Resources
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• v.34 no.4
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• pp.346-361
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• 2021

The range of D. spathulata identified in this survey was between N 35° 24' 58" ~ N 35° 26' 35", E 129° 05' 43" ~ E 129° 07' 04". It is located at an altitude of 98~592 m. The soil pH was strongly acidic in the range of 4.2~4.9, with a canopy openness of 18.56% and a chlorophyll index of 36.74 ± 2.80. As a result of the TWINSPAN analysis, 20 plots of 100 m² each were divided in 4 communities: Pinus densiflora community, Quercus monglica-Diabelia spathulata community, Quercus serrata-Diabelia spathulata community and Carpinus tschonoskii subassociation. The result of species diversity was 0.7615, and evenness and dominance were found to be 0.6077 and 0.3923, respectively. The height of D. spathulata is up to 3.4 m, and the average height is 1.1 m, with most of the species distributed as shrubbery and herbaceous. The average population density of the 20 plots was 1.635 individuals/m², the height range of flowering was 1.0 ~ 1.8 (aver. 1.39 m) and the rate of flowering was 27.37%. It's propagation pattern was mainly formed by extending the rhizome to the side, creating a colony of ground stems.

• Korean Journal of Plant Taxonomy
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• v.35 no.2
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• pp.81-98
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• 2005

Leaf morphology was examined for Prunus species from Jeju Island. Analyzed were the leaf blade length, petiole length, width of blade, number of veins and angle of the base to the mid-vein as quantitative characters and the distribution of trichome, position of glandsand leaf features qualitative characters. A total of 25 OTU were phenetically analyzed by UPGMA. The resuling phenograms slightly differ from the currently recognized taxonomic system in two points. Prunus mume was clustered with P. padus and P. buergeriana. Prunu spendula and P. yedoensis were separated from the cluster of P. jaamasakura, P. speciosa, P. sargentii and P. jamasakura var. quelpaertensis. Except for the members of subgenus Cerasus, subgenera Padus (P. buergeriana and P. padus), Microcerasus (P. japonica) and Amygdalus were well defined. Some morphological characters of leaves such as the ratio of blade length to width, the length of blade to petiole, number of veins, the distance between the gland and base, the angle of base to mid-vein, and the distribution of trichome were useful as diagnostic features for Prunus from Jeju Island.

• Journal of the Korean Data and Information Science Society
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• v.20 no.1
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• pp.179-190
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• 2009

In the financial industry, the decision tree algorithm has been widely used for classification analysis. In this case one of the major difficulties is that there are so many explanatory variables to be considered for modeling. So we do need to find effective method for reducing the number of explanatory variables under condition that the modeling results are not affected seriously. In this research, we try to compare the various variable reducing methods and to find the best method based on the modeling accuracy for the tree algorithm. We applied the methods on the pension insurance of a insurance company for getting empirical results. As a result, we found that selecting variables by using the sensitivity analysis of neural network method is the most effective method for reducing the number of variables while keeping the accuracy.

• Korean Journal of Plant Taxonomy
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• v.44 no.3
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• pp.202-207
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• 2014

Lonicera insularis Nakai (Caprifoliaceae) is Korean endemic plant that lives along the shore of Ulleungdo and Dokdo. The aim of this study is to construct a phylogenetic relationship within six species (L.maackii, L.chrysantha, L.subsessilis, L. harai, L. morrowii) of genus Lonicera L. and Wigela subsessilis as outgroup and intraspecific variation of L. insularis using chloroplast DNA five regions sequences. Sequence analysis revealed that both L. insularis and L. morrowii showed complete homologies in the intergenic regions of trnL-trnF, trnS-trnG, psbM-trnD and matK coding region. However, sequence in the petN-psbM intergenic region showed a single nucleotide difference between both species, thus we designated them as CP01 and CP02. The plants having CP01 are prevalent in the Ulleungdo and Dokdo, while L. insularis and L. morrowii from Ulleungdo and of Dokdo, and Japan have CP02. This confirmed the existence of two cp DNA lineages with different geographical distributions. We can infer the allopatric speciation by geographical barrier. The result will provide the important basal data to study speciation and specie evolution of ocean islands such as Ulleungdo and Dokdo.

• Journal of Korean Society of Forest Science
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• v.86 no.2
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• pp.146-157
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• 1997

To investigate the structure and the conservation strategy of Korean native species, Abies koreana forest at Cheonwangbong-Deokpyungbong area in Chirisan National Park, 48 plots($10{\times}10m$) were set up with random sampling method. Three groups - Abies koreana community, Abies koreana-Quercus mongolica community, Picea jezoensis-Betula ermanii community - were classified by cluster analysis. High positive correlations were shown between Picea jezoensis and Sorbus commixta : Quercus mongodica and Fraxinus sieboldiana, Symplocos chinensis : Euonymus macroptera and Vaccinium koreanum, and high negative correlations were shown between Quereus mongolica and Sorbus commixta. Species diversity(H') of investigated area was calculated 0.7208-1.2074. Vigor of Abies koreana was depressed, 12.24 of total number of Abies koreana investigated were dead. DBH of dead individuals ranged mainly 10-30cm.

• Journal of Korean Society of Forest Science
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• v.106 no.2
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• pp.130-149
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• 2017

The subalpine zone which is vulnerable to climate change could be functioning as a habitat for northern plant species especially in the Korean peninsula. In this study, classification of phytosociological community type and investigation on flora of vascular plants of Daecheongbong area in Mt. Seorak were carried out in order to provide a basic information for an ecological restoration and management of the vegetation through community ecological approach. Vegetation data were collected from 31 of quadrates from May to October, 2016. We analyzed vegetation types with phytosociological method, importance value with Curtis & McIntosh method, CCA using PC-ORD program tool, and flora of vascular plants. As a result, the forest vegetation was classified into Abies nephrolepis community. The community was divided 3 groups such as Pinus pumila group, Rhododendron brachycarpum group and Angelica decursiva group. Therefore, the vegetation had 3 kinds of units. The differential species group, it was classified into total of 7 species group units including Thuja koraiensis and Smilacina bicolor differential species group. The mean importance percentage (MIP) in VU 1 was shown Pinus koraiensis (24.1), A. nephrolepis (23.6) and Betula ermanii (10.5), and in VU 2, it was P. koraiensis (26.2), A. nephrolepis (20.8) and B. ermanii (10.5), and in VU 3, it was P. koraiensis (22.2), A. nephrolepis (16.4), B. ermanii (13.5) in the order, respectively. As for importance values of P. koraiensis and A. nephrolepis representative competition species, were different at each layers. The former (46.7) was higher than the latter (26.1) in tree layer, but the latter was higher than the former in subtree and, shrub and herb layers of VU 1. VU 2 and VU 3 also indicated the same tendency. P. pumila group and A. decursiva group were shown to have positive correlation with altitude and present species, respectively. The designated as the endemic plant was 11 taxa and, as the rare plant 24 taxa and 62.5% of vascular plant was northern plant species. It is necessary to continue further long-term monitoring of 3 vegetation units, IV of main competition species (P. koraiensis and A. nephrolepis) with stratum and main specific species (rare plants and endemic plants) considering vegetation science and, population and community ecology approaches.

• Journal of Korean Society of Forest Science
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• v.94 no.6
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• pp.410-419
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• 2005

Community structure of evergreen broad-leaved forest of Mt. Yeogwi in Jin-do was investigated to secure sustainable conservation of evergreen broad-leaved forest. Twenty survey plots of $20m{\times}20m$ were established along the elevation from 200 m to 390 m above the sea level in the northwestern slope. The woody species were tallied at each plots. DBH distribution of the major evergreen broad-leaved trees was investigated to find out the spatial distribution. Cluster analysis was applied to a set of vegetation data, that is, importance value to classify the forest community. Species diversity, evenness and species correlation were analysed. Canonical correspondence analysis was also applied to vegetation data and soil environmental data. Cluster analysis showed that the forests of Mt. Yeogwi were classified into 2 community groups, such as Camellia japonica community group and Quercus acuta community group. C japonica community group was subdivided into C japonica- evergreen broad-leaved trees community, C. japonica-Neolitsea sericea community, and C. japonica-deciduous broad-leaved trees community. Q. acuta community group was subdivided into Q. acuta-C. japonica community, and Q. acuta community. C. japonica, Q. acuta, N. sericea, Machilus thunbergii and Illicium religiosum were dominant evergreen broad-leaved tree species, while Styrax japonica, Lindera erythrocarpa, Cornus kousa, Prunus sargentii, Albizzia julibrisin and Quercus acutissima were major deciduous tree species. Species diversity was greater in Q. acuta community group (0.8231 for Q. acuta-C. japonica community, and 0.8135 for Q. acuta community) than in C. japonica community group (0.7674 for C. japonica-evergreen broad-leaved trees community, 0.6164 for C. japonica-N. sericea community, and 0.7931 for C. japonica-deciduous broad-leaved trees community). DBH 2 cm~10 cm of major evergreen broad-leaved trees occupied 80% of all. C. japonica of less than DBH 5 cm tended to aggregate but distribute randomly or regularly with increasing DBH. Q. acuta distributed more aggregately than C. japonica and Machilus thunbergii for more than 15 cm of DBH. C. japonica correlated negatively with Q. acuta, I. religiosum and C. kousa, but positively with N. sericea. with significance at 1% level. Q. acuta correlated negatively with C. japonica, N. sericea and M. thunbergii but positively with l. religiosum. There were also negative correlation between N. sericea and C. kousa. CCA showed that forest communities were correlated with soil variables such as CEC, soil organic matter and soil pH. With increased soil organic matter and CEC, and decreased soil pH, C. japonica was dominant and forest community and Q. acuta and N. sericea tended to develop in the evergreen broad-leaved forest.

• Korean Journal of Environment and Ecology
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• v.19 no.2
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• pp.75-82
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• 2005

To investigate the vegetation structure of the region from Dongchanggyo to Deogjusa in Woraksan National Park, 23 plots$(400m^2)$ set up with random sampling method were surveyed. Three groups Quercus mongolica-pinus densiflora community, Pinus densiflora-Quercus molica community, Mixed Broad-leaved community were classified by cluster analysis. Quercus mongolica, pinus densiflora, Quercus serrata and Fraxinus rhynchophyllai were found as a major woody plant species in Woraksan National Park region. In this area, Quercus mongolica and Pinus densiflora were dominated partially. In the future, the importance percentage of Pinus densiflora might be decreased, but those of Quercus mongolica, Quercus serrata and Fraxinus rhynchophyllai might be increased. High positive correlations were proved between Acer pic tum and Corylus heterophylla, Betula schimidtii; Acer pseudosieboldianum, Cornus controversa ; Stephanandra incisa and Symplocos sawafutagi, Lespedeza maximowixzii ; Symplocos sawafutagi and Fraxinus rhynchophyllai, Lespedeza maximowixzii; Fraxinus rhynchophyllai and Acer pseudosieboldianum, Lespedeza maximowixzii; Quercus variabilis and Fraxinus sieboldiana; Corylus heterophylla, and Rhododendron schlippenbachii; Acer pseudo sieboldianum and Lespedeza maximowixzii, and relatively high negative corrlations was proved between Quercus serrata and Betula schimidtii; Quercus mongolica and Quercus serrata; Corylus heterophylla and Lindera erythrocarpa. Species diversity(H') of investigated groups were ranged from $1.2393\~1.3674$ and it was relatively high compared to those of the ridge area of other national parks.