• Journal of Korean Society of Forest Science
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• v.78 no.4
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• pp.381-395
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• 1989

The main purpose of this research is to provide scientific informations about standard wage and performance tariffs in forest management with special reference to working time for thinning. To identify relationships between net working time and tree characteristics, three geographically different sample plots were established at Yangsan, Bongpyung and Jinan and 460 oaks, 372 Japanese larches, 232 red pine and 240 pitch pine mere selected at each sample plots. The results of statistical analysis using multiple regression are as follows ; 1. Five independent variables of breast height diameter(DBH), mid-diameter(MD) large end diameter(LD), log-length(L), No. of branches(NOB) were stable independent of worker and tree species. 2. Comparing correlation coefficient of five independent variables, the best predictive variables, breast height diameter and No. of branches, were selected. Breast height diameter and No. of branches were identified as the most important independent variables in terms of effect on the dependent variable of the working time. 3. Comparing coefficient of determination (Rp) and residual mean square (MSEp), the best Linear regression equation for each tree species was selected as follower : $WT=a+b1{\times}NOB+b2{\times}DBF$ 4. Proportion of hang-up time to total working time in thinning were 66% in oak stand, 74%, in Japanese larch stand, 55%, in red pine stand and 52% in pitch pine stand, respectively. 5. Based on the best regression equation, a table of working time was made by strata of number of branches and breast height diameter. 6. Total working time using the best regression equation in Table 5 can be predicted in terms of felling time, limbing time, hang-up time, i.e., total working time increases by 11 to 13 seconds with every 1 centimeter increase in breast height diameter from 7 to 16 centimeter.

• Korean Journal of Environment and Ecology
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• v.23 no.2
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• pp.143-150
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• 2009

To investigate the vegetation structure of the mountain ridges ranging of Shins un-Bong, this research set up 14 plots($400m^2$) as survey target areas. As a result of the analysis of woody plant cluster, it was classified as two groups-Quercus variabilis-Quercus serrata community and Carpinus tschonoskii community. Quercus variabilis and Quercus serrata was found as a mostly dominant woody plant species in the ridge areas of Shinsun-Bong, while Carpinus tschonoskii were mixed up partly in high altitudes. High negative correlations were shown between Quercus variabilis-Sambucus sieboldiana and relatively high positive correlation were found to exist between Styrax japonicus-Quercus serrata, Sambucus sieboldiana-Rhododendron schlippenbachii, Tilia amurensis, Styrax obassia-Cornus kousa, Rhododendron schlippenbachii-Carpinus laxiflora, Cornus kousa-Tilia amurensis. Species diversity index(H') of investigated groups were ranged from $1.237{\sim}1.497$, and it was relatively high value compared to that of the vegetation structure of other national park.

• Korean Journal of Environment and Ecology
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• v.21 no.2
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• pp.113-119
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• 2007

To investigate the vegetation structure at Orimok of Hallasan national park, 28 plots$(2,000m^2)$ were surveyed by random sampling method. Carpinus tschonoskii was a major woody species in the studied area in Orimok, and Quercus gorsseserrata, Quercus serrata, and Quercus mongolica were partly occupied. High negative correlations were shown between C. tschonoskii and Ilex macropoda, Lindera erythrocarpa, Quercus mongolica Comus walteri and Symplocos coreana, and relatively high positive correlations were proved to exist between Acer pictum var. mono and Carpinus cordata, Quercus gorsseserrata Ilex macropoda and Lindera erythrocaypa, Q. mongolica Abies nephrolepis and Prunus sargentii, Kalopanax septemlobus Taxus cuspidata and Symplocos coreana. Species diversity(H') was 0.771, and it was relatively low numerical value compared to that of other national parks.

• Korean Journal of Agricultural and Forest Meteorology
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• v.14 no.1
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• pp.39-44
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• 2012

This study was carried out to determine the relationships between cellulose decomposition and soil environmental factors in larch (Larix leptolepis) and pine (red pine: Pinus densiflora; rigitaeda pine: P. rigida ${\times}$ P. taeda) species planted in the same year (1963). The variation of cellulose mass loss with soil temperature, soil pH, soil $CO_2$ efflux rates, and soil water content was measured monthly for 4 months (July, August, September and October 2006) from three coniferous plantations. Mean mass loss rates during the study period were generally more rapid in rigitaeda pine (6.5 $mg\;g^{-1}\;day^{-1}$) than in red pine (6.2 $mg\;g^{-1}\;day^{-1}$) or larch (6.1 $mg\;g^{-1}\;day^{-1}$) plantations, although the mass loss rates were not significantly different among three tree species (P > 0.05). Cellulose mass loss rates among three tree species were positively correlated with soil temperature (red pine: r = 0.77, P < 0.05; rigitaeda pine: r = 0.59, P < 0.05; larch: r = 0.48, P < 0.05) at the 20 cm soil depth, while the mass loss rates were negatively correlated with soil pH (red pine: r = -0.63, P < 0.05; rigitaeda pine: r = -0.47, P < 0.05; larch: r = -0.43, P < 0.05). There was a significant correlation between cellulose mass loss and soil $CO_2$ efflux rates except for regitaeda pine plantation, while no significant correlation (P > 0.05) between cellulose mass loss and soil water content in larch or rigitaeda pine. The results suggest that cellulose mass loss rates in soil layers depend on the different soil environmental factors caused by tree species.

• Journal of KIISE:Software and Applications
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• v.26 no.4
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• pp.568-583
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• 1999

대량의 말뭉치(corpus)로부터 구문 정보나 의미 정보를 컴퓨터를 사용하여 자동으로 발췌하려는 연구가 활발하다. 그러나 실용적인 자연언어처리 시스템이 되기 위해 필요한 망라성(coverage)과 견고성(robustness)을 갖기 위해 어느 정도 규모의 말뭉치가 필요한지에 대한 연구는 극히 미비하다. 본 연구는 '우리말큰사전'상의 주요 4가지 품사에 속하는 단어들을 중심으로 상이 단어(different words) 수와 말뭉치 크기간의 상관관계를 통계적으로 고찰하여 수학적 예측함수(estimating functions)를 구한다. 그리고 이를 통해 자료 빈약성(data sparseness)현상을 타당한 수준으로 감소시켜 말뭉치를 기반 자연어처리의 신뢰도를 높이기 위해 요구되는 말뭉치 크기를 예측한다. 또한 예측된 말뭉치 크기를 근거로 합리적인 말뭉치 구축 방법을 제안한다.

• Journal of Forest and Environmental Science
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• v.24 no.2
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• pp.111-118
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• 2008

Pull-out resistance tests of root were carried out for 7 shrub species which are mainly used greening of deteriorated forest slope. Mean pull-out resistance forces of Aralia elata, Salix koreensis and Stephanandra incisa were 37.26 kgf, 34.56 kgf and 26.00 kgf, respectively. The pull-out resistances were high as collar diameter and volume of the root increased. Correlations between root collar diameter and root volume were high in Rubus crataegifolius, but on the other hand, the correlation was lowest in Zanthoxylum schinifolium. There were significant differences in pull-out resistance by root collar diameters, and the difference of pull-out resistance by species showed only below 20 ml root volume.

• Korean Journal of Environment and Ecology
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• v.23 no.2
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• pp.220-232
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• 2009

The objective of this study was to understand the relationships between forest vegetation characteristics and the damage of Oak wilt disease. Field surveys were carried out for two groups. One group(Group A) consists of Oak wilt infected 18 sites from 7 provinces, and the other group(Group B) consists of 5 permanent sites where data on the relative density of entrance holes drilled by Platypus koryoensis., the vector of Oak wilt disease, were available. Survey results showed that 17 of 18 sites were dominated by Quercus spp.(Group A) and also showed a significant positive relationship($R^2=0.89$, P<0.05) between the relative density of entrance holes and the relative density of Quercus spp.(Group B) implying that the susceptibility to Oak wilt disease is related with the high dominance of Quecus spp. in a forest stand.

• Korean Journal of Environment and Ecology
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• v.27 no.4
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• pp.462-472
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• 2013

This study was carried out to provide a basic data for preservation of Pinus desiflora forest as cultural landscape forest by analyzing characteristics of plant community of P. desiflora forest in Geumjeongsan(mountatin) in Busan city. In order to analyze plant community of P. densiflora in Geumjeongsan, we set up 10 study plots inside and 8 plots outside of Geumjeongsansung(mountain fortress, hereinafter 'Sansung')(unit area: $400m^2$), a total of 18 plots. TWINSPAN analysis divided these 18 study plots into 6 communities which are Querqus serrata-P. desiflora community, P. desiflora community, P. desiflora-Q. serrata community, P. thunbergii-P. densiflora community, P. densiflora-P. thubergii-Q. acutissima community, and P. densiflora-Platycarya strobilacea community. Importance Percentage (I.P.) of each area and DBH class distribution of main species showed that P. densiflora community would succeed to Q. serrata community or C. tschonoskii community. Analysis on tree age found out that communities in the Sansung were 32~37 years old and those outside the Sansung were 44~57 years old. Shannon's species diversity index ranged from 0.4826 to 1.2499. Regarding correlation between species, P. densiflora had negative correlation with Styrax japonica. Based on abovementioned result we expected ecological succession from P. densiflora community to Q. serrata community inside of the Sansung. Outside the Sansung, succession from P. densiflora-P. thunbergii community to C. tschonoskii-Q. serrata community was expected. In order to manage P. densiflora forest as cultural landscape forest, Q. spp in the understory and shrub layer and deciduous broad-leaved arboreal trees should be managed. Tree crown management of deciduous broad-leaved trees in competition with P. desiflora, is also required.

• Journal of Korean Society of Forest Science
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• v.64 no.1
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• pp.47-51
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• 1984

Hybrids among some southern pines, Pinus rigida, Pinus taeda and Pinus serotina, were tested in Chunbuk area in order to investigate their adaptability to Korean climate and soils. The results were summarized as follows; 1) Hybrids between P. rigida and P. raeda showed good growth among interspecific hybrids of southern pines tested. In particular, P. taeda${\times}$P. rigida showed remarkable growth in Chunbuk area. 2) The survival rate of P. taeda was extremely low, probably because of cold susceptibility. 3) Volume growth was correlated with width and length of cone, length of needle and needle sheath at the 1% level. 4) Hybrids were generally located between the parents in cluster analysis.

• Korean Journal of Environment and Ecology
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• v.35 no.2
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• pp.164-180
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• 2021

Plants Social Network(PSN) analysis combines the plant sociological method and the social network analysis to understand plant society focusing on environmental-to-plant and plant-to-plant relationships. PSN is at an early stage of research and require comparing plant society analyses in various environments and existing interspecies binding analysis. This study conducted a vegetation structural analysis of Mudeungsan National Park and compared the existing interspecies connection analysis with the PSN. A total of 60 plots were established for a survey on the Old Trail. The TWINSPAN and DCA analysis showed that the 60 survey plots were divided into the Quercus serrata-Pinus densiflora community (Community I) and the Quercus mongolica community (Community II) based on an altitude of 800 meters. We performed the interspecies correlation with more than 30% emergence frequency and the DCA analysis and compared the results with a focus on the major species in each colony. The results showed that Quercus serrata had a correlation of -0.450^** and -0.375^** with Pinus densiflora and Quercus mongolica, respectively. The DCA analysis also confirmed that Quercus serrata was located close to Pinus densiflora and far from Quercus mongolica along one axis. For the PSN analysis of PSN, 40 survey plots were added to investigate the species appearing in a total of 100 survey plots. The network structural analysis showed 378 links and a species having an average of 6 interspecies bindings. The density was 0.097, the diameter was 7, and the average path distance was 2.788, similar to the PSN analysis results of the Busan Metropolitan City. The plant social network analysis showed similar results to the existing interspecies combination analysis, enabling analyzing more data than the existing methods and observing the structure of plant society.