• Journal of Forest and Environmental Science
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• v.11 no.1
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• pp.72-80
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• 1995

Altitudinal effects on the accumulation of O layer were examined for deciduous broad-leaved forests in the experimental forest of Kangwon National University. There found a marked increased towards the higher altitudes in the thickness of O layer. These trends could be observed conspicuously on the F2 and H layers. The relation between thickness (X, cm) and dry weight (Y, $kg/m^2$) of O layer was approximated by linear regression equations;Y($kg/m^2$ = aX(cm). The values of coefficient "a" for the F2, H and F2+H layers were 0.43, 0.61 and 0.53, respectively. Bulk densities of the accumulated organic matter estimated nearly to be $45g/dm^2$ in F2 layer, $60g/dm^2$ in H layer and $55g/dm^2$ in F2+H layer. The amount of O layer ranged from 13ton/ha for the forest at 280m in altitude to 41ton/ha for the upper forest at 710m in altitude. Among these total amount of the O layer, F1, F2 and H layer occupied to be 5~10ton/ha, 5~11ton/ha and 13~40ton/ha, respectively.

• Journal of Forest and Environmental Science
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• v.21 no.1
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• pp.75-82
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• 2005

The experimental study was carried out to evaluate the performance of underplanted Pinus koraiensis 2-2 seedlings in the closed canopy natural deciduous forest. Overstory density effects on seedling survival and growth were assessed 7 years after underplanting. Seedling survival rate was 80%, average height was 0.9m with minimum of 0.3m and maximum of 2.1m, and average diameter at butt end was 1.7cm with minimum of 1.4cm and maximum of 3.5cm. Compared with the growth rate of the pine plantation after clearcutting, the growth performance of underplanted pine seedlings was so poor that the height growth was less than 30% and diameter growth was less than 20%. Even though the Pinus koraiensis seedlings would be shade tolerant, the establishment and performance of underplanted Pinus koraiensis seedlings could be promoted by more than 50% of canopy regulation that provide adequate light at the forest floor and should exhibit a strong positive response following overstory removal by tending operation.

• Journal of Korean Society of Forest Science
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• v.108 no.1
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• pp.21-28
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• 2019

This study was conducted to determine the carbon (C) and nitrogen (N) response of litterfall components as affected by N addition in compound fertilizer in a Korean red pine (Pinus densiflora S. et Z.) stand in southern Korea. Litterfall in a mature red pine stand was collected for two years following compound fertilizer application ($N_3P_4K_1$; $P_4K_1$) and no fertilization (control). The C concentration of litterfall components was not significantly (P > 0.05) different between the $N_3P_4K_1$ and the control plots, whereas the N concentration of the litterfall components was significantly higher in the $N_3P_4K_1$ plot than in the control plot. The $N_3P_4K_1$ and $P_4K_1$ additions induced a lower C/N ratio of litterfall components compared with the control plot. Annual C and N fluxes via litterfall components were not affected by the $N_3P_4K_1$ addition over the study period, except for reproduction litter. Annual N fluxes via reproduction litter were significantly higher in the $N_3P_4K_1$ plot than in the control plot. Thus, the $N_3P_4K_1$ and $P_4K_1$ additions could modify differently nutrient distribution of the forest floor and mineral soils in a red pine stand. These results indicate that N concentration and C/N ratio in litterfall components are more susceptible to fertilizer application than the C response in litterfall components.

• Steel and Composite Structures
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• v.44 no.1
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• pp.49-63
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• 2022

This study aims to develop ensemble machine learning (ML) models for estimating the peak floor acceleration and maximum top drift of steel moment frames. For this purpose, random forest, adaptive boosting, gradient boosting regression tree (GBRT), and extreme gradient boosting (XGBoost) models were considered. A total of 621 steel moment frames were analyzed under 240 ground motions using OpenSees software to generate the dataset for ML models. From the results, the GBRT and XGBoost models exhibited the highest performance for predicting peak floor acceleration and maximum top drift, respectively. The significance of each input variable on the prediction was examined using the best-performing models and Shapley additive explanations approach (SHAP). It turned out that the peak ground acceleration had the most significant impact on the peak floor acceleration prediction. Meanwhile, the spectral accelerations at 1 and 2 s had the most considerable influence on the maximum top drift prediction. Finally, a graphical user interface module was created that places a pioneering step for the application of ML to estimate the seismic demands of building structures in practical design.

• The Korean Journal of Ecology
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• v.6 no.1
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• pp.22-32
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• 1983

The paper is investigation of the secondary vegeation and succession at the forest fire area in Mt. Palgong. The survey was carried out from April, 1981 to Stempter, 1982. The floristic compositions were as follows: 50 families, 116 genera, 127 species, 15 varieties and 3 formae(145 kinds). Among them, the floristic composition of the pine floor vegetation of the unburned area was 43 families, 80 genera, 88 species, 10 varieties and 1 forma(99 kinds), and that of the secondary vegetatiion after forest fire was 46 families, 106 genera, 120 species, 14 varieties and 3 formae(137 kinds). Index of similarity between the burned and unburned area was 0.77. The biological type succeeded in $H-D_1-R_5$type, and the erect form(s) was prevailed. Carex humilis var. nana, Miscanthus sinensis var. purpurascens, and lespedeza cyrtobotrya were dominant species in the $ B_1; and; B_2$ area of the seventh year after forest fire. In the degree of succession, species diversity, and evenness index, DS, H, and e of the $B_1$ area were higher than those of the $B_2$ area. In the soil properties, it assumed that pH, total nitrogen, and available phosphores of the burned area were nearly recovered to those of the unburned area.

• 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.

• Journal of Ecology and Environment
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• v.43 no.2
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• pp.161-182
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• 2019

Quantifying the amount of carbon pools in forest ecosystems enables to understand about various carbon pools in the forest ecosystem. Therefore, this study was conducted in the Chilimo dry afromontane forest to estimate the amount of carbon stored. The natural forest was stratified into three forest patches based on species composition, diversity, and structure. A total of 50 permanent sample plots of 20 m × 20 m (400 ㎡ ) each were established, laid out on transects of altitudinal gradients with a distance of 100 m between plots. The plots were measured twice in 2012 and 2017. Tree, deadwood, mineral soil, forest floor, and stump data were collected in the main plots, while shrubs, saplings, herbaceous plants, and seedling data were sampled inside subplots. Soil organic carbon (SOC %) was analyzed following Walkely, while Black's procedure and bulk density were estimated following the procedure of Blake (Methods of soil analysis, 1965). Aboveground biomass was calculated using the equation of Chave et al. (Glob Chang Biol_20:3177-3190, 2014). Data analysis was made using RStudio software. To analyze equality of means, we used ANOVA for multiple comparisons among elevation classes at α = 0.05. The aboveground carbon of the natural forest ranged from 148.30 ± 115.02 for high altitude to 100.14 ± 39.93 for middle altitude, was highest at 151.35 ± 108.98 t C ha^-1 for gentle slope, and was lowest at 88.01 ± 49.72 t C ha^-1 for middle slope. The mean stump carbon density 2.33 ± 1.64 t C ha^-1 was the highest for the middle slope, and 1.68 ± 1.21 t C ha^-1 was the lowest for the steep slope range. The highest 1.44 ± 2.21 t C ha^-1 deadwood carbon density was found under the middle slope range, and the lowest 0.21 ± 0.20 t C ha^-1 was found under the lowest slope range. The SOCD up to 1 m depth was highest at 295.96 ± 80.45 t C ha^-1 under the middle altitudinal gradient; however, it was lowest at 206.40 ± 65.59 t C ha^-1 under the lower altitudinal gradient. The mean ecosystem carbon stock density of the sampled plots in natural forests ranged from 221.89 to 819.44 t C ha^-1. There was a temporal variation in carbon pools along environmental and social factors. The highest carbon pool was contributed by SOC. We recommend forest carbon-related awareness creation for local people, and promotion of the local knowledge can be regarded as a possible option for sustainable forest management.

• Journal of Environmental Science International
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• v.19 no.12
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• pp.1397-1402
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• 2010

In recently, building greening to improve the urban environment is a very important areas. Thus, in order to promote the building greening is needed for the arrangement of its related system. In this study, analyzed the related system in Japan and the results obtained are as follows. Related system in Japan are to promote the spread of compulsory and dissemination of guidance. And to promote the spread of dissemination of guidance are to allowed a system to be included in green area of the site required, plans to loan the costs of greening, plans to subsidize the cost of greening, tax reduction and exemption, incentive on floor area ratio, plant supply and other technical guidance system. In conclusion, in order to promote the building greening note the related system of Japan and our related system should be arranged.

• Journal of Korean Society of Forest Science
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• v.86 no.2
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• pp.200-207
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• 1997

The throughfall, stemflow and precipitation interception during the period of May to November 1995 were compared between three stands of Pinus koraiensis, Larix leptolepis and Quercus species stand growing at Kwangju-Gun, Kyunggi-Do. The total amount of precipitation during the period in the study area was 1,821mm, higher than average precipitation. The amount of interception showed 21.8% of the total precipitation in Quercus stand, whereas 15.7 and 19.4 in P. koraiensis and L. leptolepis stands, respectively. Precipitation leached on forest floor was occupied mainly by throughfall for all the stands, and it was specially higher in P. koraiensis stand. The amount of stemflow was appeared higher in Quercus stand(5.0%) than P. koraiensis stand(1.1%) or L. leptolepis stand(1.1%). The relationship between throughfall or stemflow and total precipitation in all the stands were highly significant.

• The Korean Journal of Ecology
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• v.19 no.5
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• pp.417-430
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• 1996

This study was conducted to investigate the developmental process of plant community during the secondary succession and the dynamics of soil properties in the burned and unburned areas of Mt. Ch’oly-san. Owing to the forest fire occurred on April, 1989, the red pine(Pinus densiflora) forest and its floor vegetation were burned down. The floristic composition of burned and unburned areas were composed of 53 and 49 species of vascular plants, respectively. The dominant species based on SDR4 of the burned sites were lespedeza cyrtobotrya (89.62), Miscanthus sinensis var. purpurascens (62.50), and Carex humilis (58.73), Quercus serrata (43.33). In contrast, Pinus densiflora (83.56), Lespedeza cyrtobotrya (55.57), Miscanthus sinensis var. purpurascens (51.88) and Carex humilis (50.41) were dominant in the unburned area. The biological spectra showed the $H-D_1-R_5-e$ type in both the burned and unburned areas. The indices of similarity ($CC_S$) between the two areas were 0.74. Degree of succession (DS) was 604 in the burned area and 802 in the unburned area. From these facts, it is assumed that the succession is rapidly progressing because of the recovery of vegetation. The species diversity ($\={H}$) and evenness index(C) in the burned and unburned areas were 0.15 and 0.18, respectively. Red pine tree did not resprout after scorch by the forest fire, but Lespedeza, Quercus, Rhododendron, Albizzia, and Zanthoxylum resprouted from the roots and trunks after the forest fire. It seems that these species are the fire-resistant species. Soil properties such as soil pH, content of organic matter, available phosphous, total nitrogen, tatal carbon, exchangeable potssium, sodium, calcium, and magnesium increased due to forest fire. These results suggest the intensity of forest fire in the study area was relatively weak. Monthly changes of soil properties were of little significance except for some cases.