• Journal of Korean Society of Forest Science
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• v.95 no.3
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• pp.370-377
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• 2006

This study was conducted to develop an efficient method of sampling design appropriate for the sustainable forest management. For this, data were collected in Yangpyung-Gun, Gyunggi Province based on three different sampling designs such as systematic design, systematic cluster design, and stratified cluster design. Based on evaluation statistics, the sampling designs were compared to select a sampling method fitted to sustainable forest management. It was found that the systematical cluster sampling is the most efficient sampling method in terms of feasibility for sustainable forest management. It was also recommended that the sample plots should be made as a cluster of triangle-shape. The clusters should be consisted of a main plot and three sub-plots. And the sub-plots should be arranged with a distance of 50m from the main plot in the center of cluster.

• Journal of Korean Society of Forest Science
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• v.99 no.5
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• pp.736-743
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• 2010

This study examined the ecological attributes of classified forest community by cluster analysis in the mixed forest of Mt. Seokbyung Experimental Forest of Gangwon-Do. The vegetation data were collected in randomly established 51 sample plots (2.04 ha) and analysis adopted the cluster analysis, importance value index, and Shannon's diversity index. Main results were as follows; 1) the study area was classified into 4 clusters (A, B, C and D). 2) The cluster A was dominated by Pinus densiflora with an importance value of 71.6%. The most dominant species in the cluster B and cluster C were Larix leptolepis (57.1%) and Quercus mongolica (40.2%), respectively. Finally, The cluster D was dominated by P. densiflora (30.6%) and Q. mongolica (31.0%) with the mixed forest. 3) In the P. densiflora community (cluster A), distribution of DBH class showed a reverse J-shaped curve. In the L. leptolepis community (cluster B), individuals of dominant species had the bell-shaped distribution. Oak species indicated uniform distribution of DBH class (under 25 cm) in the mixed P. densiflora - Q. mongolica community (cluster D). 4) The species diversity index of the communities in descending order were: Pinus densiflora - Q. mongolica community > Larix leptolepis community > Pinus densiflora community > Quercus mongolica community.

• Journal of Korean Society of Forest Science
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• v.99 no.3
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• pp.304-311
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• 2010

Korea National Forest Inventory System has been adopting different cluster plot design and new equations to estimate growing stock volumes since 2006. These changes have resulted in volume estimations which show some difference from previous ones. This study is to find out the source of such difference. For this, relevant data was collected from 80 plots of 20 cluster samples according to the cluster plot design applied to 4th and 5th National Forest Inventory. Then growing stock volumes were estimated by using current and previous individual tree volume equations respectively. An investigation was made to detect whether such difference in volume estimates was originated from the changes in cluster plot design or from using different volume equations. T-test results showed that the difference from changes in cluster plot design was negligible. Instead, changes in volume equations had statistically significant effects in volume estimation. Since the volume estimation by the 5th National Forest Inventory would bring overestimation by applying different volume equations, all the volume estimations made prior to 2006 would require necessary modifications for international reporting.

• Journal of The Korean Astronomical Society
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• v.44 no.5
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• pp.195-200
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• 2011

We have revisited the ACS Virgo Cluster Survey (ACSVCS), a Hubble Space Telescope program to obtain ACS/WFC g and z bands imaging for a sample of 100 early-type galaxies in the Virgo Cluster. In this study, we examine 51 nucleated early-type galaxies in the ACSVCS in order to look into the relationship between the photometric and structural properties of stellar nuclei and their host galaxies. We morphologically dissect galaxies into five classes. We note that (1) the stellar nuclei of dwarf early-type galaxies (dS0, dE, and dE,N) are generally fainter and bluer with g > 18.95 and (g-z) < 1.40 compared to some brighter and redder counterparts of the ellipticals (E) and lenticular galaxies (S0), (2) the g-band half-light radii of stellar nuclei of all dwarf early-type galaxies (dS0, dE, and dE,N) are smaller than 20 pc and their average is about 4 pc, and (3) the colors of red stellar nuclei with (g - z) > 1.40 in bright ellipticals and lenticular galaxies are bluer than their host galaxies colors. We also show that most of the unusually "red" stellar nuclei with (g-z) > 1.54 in the ACSVCS are the central parts of bright ellipticals and lenticular galaxies. Furthermore, we present multi photometric band color - color plots that can be used to break the age-metallicity degeneracy particularly by inclusion of the thermally pulsing-asymptotic giant branch (TP-AGB) phases of stellar evolution in the stellar population models.

• Communications for Statistical Applications and Methods
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• v.15 no.1
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• pp.65-76
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• 2008

Biplots are the multivariate analogue of scatter plots. They approximate the multivariate distribution of a sample in a few dimensions, typically two, and they superimpose on this display representations of the variables on which the samples are measured(Gower and Hand, 1996, Chapter 1). And the relationships between the observations and variables can be easily seen. Thus, biplots are useful for giving a graphical description of the data. However, this method does not give some concise interpretations between variables and observations when the number of observations are large. Therefore, in this study, we will suggest to interpret the biplot analysis by applying the K-means clustering analysis. It shows that the relationships between the clusters and variables can be easily interpreted. So, this method is more useful for giving a graphical description of the data than using raw data.

• Journal of Korean Society of Forest Science
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• v.83 no.4
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• pp.486-497
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• 1994

The objective of this study was to examine the effects of air pollution on Pinus thunbergii forests surrounding Sasang industrial complex in Korea. The injury index, contents of chlorophyll and mineral elements, and concentrations of water soluble sulfur in needles were investigated at sample plots surrounding industrial complex and compared with those of control far from industrial complex. The results obtained are as follows ; 1. Discoloration of Pinus thunbergii needles was severe in the vicinity of industrial complex, and the older needle age classes was the more severe its injury appeared. Injury index was increased in the vicinity of industrial complex. 2. Water-soluble sulfur concentration was high in the vicinity of industrial complex at all of needle age classes, and those of all plots were higher than that of control. 3. Chlorophyll a contents were lower at surrounding industrial complex than that at control. It was supposed that chlorophyll a was destroyed by air pollutants. Total chlorophyll contents and content ratio of chlorophyll a to b were influenced by decrease of chlorophyll a contents. 4. Phosphorus contents in needles were decreased even in remoted regions with the increase of needle age classes. Colcium contents in needles were decreased near industrial complex at all needle ages classes. 5. There were negative correlation, between injury index and chlorophyll contents, injury index and calcium contents, and there were positive correlation between injury index and calcium contents. 6. Cluster analysis was carried out to divide the injured regions on sample plots. As a result of the analysis, there were devided 3 regions, severe regions(1-8 plots), medium regions(9, 10, 11, 12, 15, 17 plot), slight(13, 14, 16, 18, 19 plot and control). 7. The cross section of visible injured needle showed the destruction of mesophyll cell, sclerenchyma cell in the outside of resin duct and endodermis, partially.

• Journal of Magnetics
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• v.12 no.4
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• pp.149-151
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• 2007

The AlCrN films were grown by RF reactive sputtering method under the selected conditions. The Cr concentration was varied by the number of Cr pieces placed on the Al target. The sample quality has been studied by XRD, Auger spectroscopy, optical absorption and electrical resistant measurements. The XRD and Auger results show that the samples consist of a major phase with the $Al_{1-x}Cr_xN$ formula, which has a hexagonal structure, and a few percents at. of oxygen, which may form $Al_2O_3$. There exist the Cr clusters in the samples with high concentration of Cr. The optical absorption measurement provides the information about the band gap that relates strongly to the quality of samples. The quality of samples is also clearly reflected in electrical measurement, i.e., the temperature dependence of resistance exhibits a semiconductor characteristic only for the samples that have no Cr cluster. In these cases, the values of ionization energies $E_a$ can be derived from R(T) plots by using the function R(T) = Ro exp $(E_a/k_BT)$.

• Journal of Korean Society of Forest Science
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• v.101 no.1
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• pp.138-147
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• 2012

For biomass estimation of Phyllostachys pubescens stands by optimal survey method we established 9 bamboo sample plots in the research forests of KFRI (Korea Forest Research Institute). The dry weight of culm segment determined by relative heights of total bamboo height show us two groups of 1st to 5th culm segment (up to 0~55% culm of tree height from the bottom area) and 6th to 8th culm segment (55~100%) by the results of cluster analysis for dry weight ratio. This results show that upper and lower part of 55~70% reference height from the bottom area against total culm height can be used in obtaining 1 kg of a sample bamboo, respectively, rather than 2.0 m stem segments of other forest tree species. In above-ground biomass estimation by $W=aD+bD^2$ having the highest coefficient of determination in this study, above ground stand biomass was 57.77 ton/ha (culm 40.47 ton/ha, branch 9.29 ton/ha, and leaf 8.01 ton/ha) of which 70% was contributed by culm component followed by branch (16%) and leaf (14%). Below-ground biomass was 53.35 ton/ha in total.

• Journal of Korean Society of Forest Science
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• v.105 no.1
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• pp.19-41
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• 2016

This study examined the flora and community classification in the Forest Genetic Resources Reserves (FGRR) at Mt. Daeseng and Juparyeong to understand the degree of disturbance and the state of forest stand development within the Civilian Control Line (CCL) and to provide baseline data for preservation and management. Of the vascular plants dispersed throughout the study site, there were 98 families, 311 genera, 507 species, 6 subspecies, 65 varieties, and 10 forms, for a total of 588 taxa. Of these, 92 families, 290 genera, 459 species, 6 subspecies, 58 varieties, and 9 forms, for a total of 532 taxa of native plants, were determined to be dispersed around the FGRR at Mt. Daeseng, and 94 families, 259 genera, 364 species, 6 subspecies, 50 varieties, and 8 forms, for a total of 428 taxa of native plants, were confirmed to be dispersed around the FGRR at Juparyeong. There were 21 taxa of endemic Korean plants growing in the FGRR at Mt. Daeseng, with 14 taxa growing in the FGRR at Juparyeong. In terms of rare plants, 26 taxa were confirmed in the FGRR at Mt. Daeseng, and 10 taxa were confirmed in the FGRR at Juparyeong. A Cluster analysis was performed using vegetation data taken from 58 sample plots in each FGRR. The results showed a total of three representative community classifications from Mt. Daeseng: mixed mesophytic forest, Quercus mongolica-Acer pseudosieboldianum, and Quercus mongolica-Fraxinus rhynchophylla communities. Four representative community classifications were observed from Juparyeong: Quercus mongolica-broad leaved forest, Fraxinus rhynchophylla-broad leaved forest, Quercus mongolica, and Quercus communities. On the whole, the species diversity of the communities in Mt. Daeseng FGRR was greater than for the communities in Juparyeong FGRR. At Mt. Daeseng, the mixed mesophytic forest had the highest species diversity index at 1.590, while at Juparyeong, the Fraxinus rhynchophylla-broad leaved forest had the highest species diversity index at 1.319. These study results should serve as useful baseline data for future preservation and management of the demilitarized zone (DMZ) and the surrounding area.

• Journal of agriculture & life science
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• v.50 no.1
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• pp.105-115
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• 2016

This study was carried out to establish the optimum forest management plan for the Cryptomeria japonica plantations in southern inland and Jeju island in Korea. Sixty seven circular sample plots of 0.04ha were established and we surveyed vegetation structure and growth characteristics from three layers(upper, middle, and lower). As a result of cluster analysis obtained by importance values of each tree species, the community type of C. japonica stands were classified into C. japonica group(C1) and C. japonica-C obtusa group. C. obtusa community were also sbudivided into P. thunbergii-Q. serrata group(C2) and Q. serrata-C obtusa group(C3). In tree layers importance value(IV) of C. japonica were 97.2% in C1, 80.7% in C2, and 47.6% in C3 and in sub-tree layers IV were 8.9% in C1, 15.2% in C2, and 5.7% in C3. Especially in C3 there are bamboo species (Smilacina japonica var. lutecarpa and Pseudosasa japonica) it is necessary for us to control them. In shrub layers C. japonica were found in C1(9.2%) and C2(7.0%), but except for C3. In tree layer species diversity indices of each community ranged from the lowest 0.059 in C1 to the highest 0.548 in C3. Dominance ranged from 0.958 in C1 to 0.393 in C3 which may caused by interspecific competition. Current annual increment of diameter growth ranged from 7.01mm/yr to 8.04mm/yr. As a result of our study we recommend the application of proper thinning and pruning for C1 and C2.