• Journal of the Korean Applied Science and Technology
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• v.32 no.1
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• pp.148-156
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• 2015

In this study the differences in the sample size and sample input changes as characteristics of bio-oil oak(Quercus variabilis), the oak 0.5~2.0 mm of the oak weighing 300~900g was processed into bio-oil via fast pyrolysis for 1.64 seconds. In this study, the physico-chemical properties of biooil using oak were investigated. Fast pyrolysis was adopted to increase the bio-oil yield from raw material. Although the differences in sample size and sample input changes in the yield of pyrolysis products were not significantly noticeable, increases in the yield of bio-oil accounted for approximately 60.3 to 62.1%, in the order of non-condensed gas, and biochar. When the primary bio-oil obtained by the condensation of the cooling tube and the seconary bio-oil obtained from the electric dust collector were measured separately, the yield of primary bio-oil was twice as higher than that of the secondary bio-oil. However, HHV (Higher Heating Value) of the secondary bio-oil was approximately twice as higher than that of the primary bio-oil by up to 5,602 kcal/kg. The water content of the primary bio-oil was more than 20% of the moisture content of the secondary bio-oil, which was 10% or less. In addition, the result of the elemental analysis regarding the secondary bio-oil, its primary carbon content was higher than that of the primary bio-oil, and since the oxygen content is low, the water content as well as elemental composition are believed to have an effect on the calorific value. The higher the storage temperature or the longer the storage period, the degree of the viscosity of the secondary bio-oil was higher than that of the primary bio-oil. This can be the attributed to the chemical bond between the polymeric bio-oil that forms during the storage period.

• Journal of Korean Society of Forest Science
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• v.112 no.1
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• pp.57-70
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• 2023

In recent years, the frequency of warnings about particulate matter (PM) has gradually increased in Korea, along with an increase in its intensity. Because of their vast surface area, reactivity to external particles, and characteristics of their leaves, urban trees can act as biofilters, reducing PM pollution. However, the air pollutant PM can cause various types of damage not only to human health but also to vegetation. Studies performed to date on the responses of trees to PM are still insufficient. Here, we analyzed the correlation between PM adsorption and physiological and biochemical responses of four major street tree species, namely, Abies holophylla, Acer buergerianum, Pinus densiflora, and Quercus variabilis, under conditions of approximately 300 ㎍ m^-3 of fly ash emissions using a phytotron. The results showed that the physiological and biochemical responses and PM adsorption differed depending on the tree species. In correlation analysis, it was confirmed that there were positive correlations between physiological factors, and PM adsorption on adaxial leaf surfaces negatively impacted the physiological characteristics. This study provides fundamental information for selecting tree species to reduce PM pollution and develop sustainable urban forests.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.32 no.2
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• pp.116-123
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• 2014

The description of vegetation cover and floral composition was undertaken in terms of phytosociological study in Dodamsambong(scenic site no. 44) and Danyangseokmoon(no. 45). In this study a total of 17 $relev{\acute{e}}s$ containing 144 taxa were collected and analyzed. Eight plant communities are differentiated, grouped into 4 physiognomic types: forest type(Buxus microphylla var. koreana-Thuja orientalis community, Tilia mandshurica-Quercus variabilis community, and Cynanchum wilfordii-Pinus densiflora community), mantle type(Cardamine leucantha-Neillia uekii community), secondary meadow type(Galium kinuta-Spodiopogon sibiricus community, Diarthron linifolium-Zoysia japonica community), and crevice type(Patrinia rupestris-Selaginella stauntoniana community, Hypodematium glandulosopilosum community). The vegetation of Dodamsambong and Danyangseokmoon is characterized by local flora, such as calciphilous plants, geological distribution-limit species, and endemic species. The soil depth, slope, and human impact have been identified as the most important differentiating ecological factors. Buxus microphylla var. koreana-Thuja orientalis community, Tilia mandshurica-Quercus variabilis community, and Patrinia rupestris-Selaginella stauntoniana community were evaluated highly by National Vegetation Naturalness. In order to restore the value of specific landscape for scenic site, we should improve the problems of protected area such as wrong management on habitat, forest fragmentation by facilities and decline in vegetation by lack of growing the next succession.

• Journal of the Korean Wood Science and Technology
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• v.42 no.4
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• pp.460-466
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• 2014

To evaluate wood charcoal as raw material for mineral water production, dissolution of inorganic ions from charcoal to water, pH and adsorption ability of chlorine in water were investigated as main variables. More potassium ion was dissolved in water as higher temperature manufactured charcoal but other ions showed no difference with different charcoal making temperatures. Highest dissolved cation was potassium followed by calcium and sodium. Among wood species, charcoal from Quercus variabilis and Platanus occidentalis showed significantly higher potassium content in water than that of larch, red pine and white pine. Other cations had similar pattern to the potassium but their difference was not apparent as much as potassium. pH value of water treated with charcoal was higher for wood charcoals from Platanus occidentalis (pH 8.5) and Quercus variabilis (pH 8.4) which contained higher inorganic cations. In chlorine removal in water by charcoal, all wood charcoals showed greater chlorine removal than that of the control, but softwood charcoals resulted in higher removal than those of hardwoods. There was no significant difference in the dissolution of cations and pHs between particle charcoal and whole charcoal. With easy of control, whole charcoal is better for mineral water making raw material than particle charcoal does.

• Journal of Korean Society of Forest Science
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• v.106 no.2
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• pp.150-168
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• 2017

This study was carried out to compare stand structure in Bihwajin basin Samcheok-si, Gangwon-do, Korea for ten years between 2003 and 2014, in which occurred the east coastal forest fire in 2000. Data were collected from 32 quadrates that followed by the analysis of vegetation classification according to plant sociology, importance value by Mclntosh and Curtise, species diversity and similarity index. In the result of vegetation classification, the vegetation unit decreased from 7 units to 4 units, and the number of species groups changed from 11 to 7. As a result of importance value (IV) changes, IV of Quercus mongolica, Q. serrata and Q. variabilis was increased by 6.8%, 5.2% and 2.9% in the order, respectively. However, that of Pinus densiflora was decreased by 2.8%. That of major planted species such as Castanea crenata, Chionanthus retusa, Prunus armeniaca var. ansu, Acer triflorum and Koelreuteria paniculata was reduced. As a result of species diversity, it was increased from 0.252 to 0.287 in tree layer, from 0.252 to 0.434 in subtree layer, and from 1.293 to 1.333 in shrub layer. But that in herb layer was decreased from 1.745 to 1.646. As a result of similarity index, it was 0.78, 0.65, 0.72 and 0.55 by layers that showed most difference in herb stratum. Considering the results, this study would be applied to the ecosystem diagnose and management of forest fire damaged area similar to the investigated area.

• Journal of Korean Society of Forest Science
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• v.77 no.2
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• pp.166-177
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• 1988

To investigate the structure of the plant community of the Naejang Temple District in Mt. Naejang National Park, 22 plots were set up by the vegetation physiognomy and vegetation analysis by four kinds of ordination techniques(PO, PCA, RA and DCA) was carried out. Pure and mixed forest community of Quercus variabilis and Q. mongolica were major forest communities and each of them covered 31.27 and 20.77%, respectively. The degree of human disturbance of vegetation 9, 8, 7 and 6 area covered 30.9, 67.0, 0 and 0.02%, respectively. According to stand dynamic analysis by DBH class distribution, the present Pinus densiflora and Quercus communities may be succeeded to Carpinus laxiflora communities. DCA was the most effective method of this study. DCA ordination showed that successional trends of tree species seem to be from P. densiflora through Q. variabilis, Q. aliena, Sorbus alnifolia, Platycarya strobilacea to Carpinus laxiflora, Fraxinus rhynchophylla, Zelkova serrata, Cornus controversa in the tree layer, and from Rhododendron mucronulatum, Rh. schlippenbachii, Lespedeza cyrtobotrya, Rhus trichocarpa through Styrax japonica, Daphniphyllum macropodum, Sapium japonicum to Euonymus oxyphyllum, E. sieboldiana, Lindera erythrocarpa in the subtree layer.

• Journal of Korean Society of Forest Science
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• v.82 no.4
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• pp.406-419
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• 1993

In spite of the economical and sivicultural importance, tending methods of natural broad leaf tree have not been established in Korea. In the present study, the structure of crown and biomass of Quercus variabilis were analyzed to obtain the basic information on pruning practice. There was not correlated between clear length of sample tree and tree height and D.B.H. The stratum with the largest leaf and branch weight was lower part of the stratum with the largest branch increment. The degree of contribution of branch to knotless trunk production (${\Delta}{\omega}_B(Z)/{\omega}_B(Z)$ and ${\omega}_L(Z)/{\omega}_B(Z)$) decreased from the upper part to the lower part. As an example of the application of the ecological data to pruning practice, the author attempted to estimate the effect of pruning with this experimental stand. Two methods of pruning were investigated. One is the removal of branches according to a definite external indication such as clear length rate of branch, and the other is the removal of barnches according to a definite height.

• Korean Journal of Ecology and Environment
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• v.50 no.1
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• pp.126-136
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• 2017

We describe characteristics of diversity and distribution of oak forests on the Daegok-cheon gorge of the Southeastern Korean Peninsula, the oldest prehistoric site, in view of a sort of food resources of acorns. The $Z{\ddot{u}}rich$-Montpellier School's method was adopted for field investigation on the oak dominant stands. A total of 20 phytosociological $relev\acute{e}s$ composed of 193 taxa were analyzed by syntaxonomy and ecological flora. The Daegok-cheon's oak forests occupied 36.9% ($513,374m^2$) of the surveyed area, and its 99% ($507,677m^2$) was Quercus variabilis and Q. serrata stands. Oak forests of the Daegok-cheon gorge are a kind of regional vegetation type characterizing by the high relative net contribution degree (r-NCD) of Platycarya strobilacea and Sapium japonicum, which are an edaphic type of the xerophilous and thermophilic oak forests. The region of the Daegok-cheon petroglyphs is defined as an ecoregion with rich acorn supply and abundant water resources, and the warmer environment, which attracts prehistoric man.

• Journal of Korean Society of Forest Science
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• v.89 no.2
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• pp.185-197
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• 2000

This study was carried out to research structure of forest vegetation and site condition, and supply basic data for conservation of pine forest and ecologically sustainable forest management and control in Anmyondo area. The forest of Anmyondo were largely classified as four forest community : Pinus densiflora community, Pinus thunbergii community, Pinus rigida community, and Quercus variabilis community. Organic matter, total nitrogen, and other nutrients in soil of the study area were relatively low, and average soil pH was 4.9. Soil texture was sandy clay or heavy clay and so the aeration and permeability could be poor. In this study site, the methods such as the promotion of germination of pine seeds through removal of forest floor and inducement of natural regeneration through such method as regeneration under shelter wood would be better than the method such as afforestation after clear-cutting for conservation the pine forests. Also, it will be a good method to practice tending for hardwood species in the dominant areas by hardwood species.

• Korean Journal of Environment and Ecology
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• v.9 no.1
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• pp.15-29
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• 1995

To investigate plant community structure of Uiryung valley, Harujae valley, Kugi valley, Songchu valley, Tobongsan valley in Bukhansan National Park, each thirty eight, forty, twenty six. twenty eight, thirty six plots (plot size 100$m^2$) were set up and surveyed. The surveyed data were integrated and classification by TWINSPAN and DCA ordination techniques were applied to the study area. The plant community were divided into nine groups in seventy nine plots by TWINBPAN and the dividing groups were Carpinus laxiflora community(I), Quercus mongolica community(II), Pinus densiflora community(III), Q. mongolica-P. densiflora community(IV) Q. mongolica-Q. serrata- Prunus sargentii community(V), Q. mongolica Q. variabilis community(Ⅵ), Robinia pseudoacacia-Q. serrata community(Ⅶ). P. rigida-Q. serrata community(Ⅷ), Q. mongolica- Q. variabilis- Styrax obassia community(Ⅸ). So the successional trends of tree species at the natural forest seem to be from P. densiflora to Q. mongolica and at the artificial forest seem to be from R. pseudoacacia, P. rigida to Q. acutissima, Fraxinus rhynchophylla in canopy layer And in the subtree and shrub layer, it wag supposed that from Deotzia prunifolia, Rhus trichocarpa. Rhododendron yedoense var. poukhasleilse, Euonymus oxyphyllous to Magnolia sieboldii, Acer psuedo-sieboldianum, Lindera obtusiloba. In comparing successional trends with past study, it was postulated that successtion is not progressed by human disturbance and soil acidification by the air pollution.