• Journal of Forest and Environmental Science
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• 제11권1호
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• pp.72-80
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• 1995

강원대학교 부속 연습림의 낙엽활엽수림에서 임상유기물(O층)의 집적에 미치는 표고의 영향을 조사하였다. 표고가 높아짐에 따라 O층의 두께는 증가하였으며, 이러한 경향은 F2층과 H층에서 뚜렷하였다. O층의 두께(X, cm)와 무게(Y, $kg/m^2$)의 관계는 직선회귀식 Y($kg/m^2$) = aX(cm)에 근사였으며, F2층, H층 및 F2 + H층에 대한 계수 "a" 의 값은 각각 0.43, 0.61 및 0.53이었다. 유기물의 용적중은 F2층, H층 및 F2+H층에서 각각 $45g/dm^2$, $60g/dm^2$ 및 $55g/dm^2$ 전후로 추정되었다. O층의 양은 표고 280m에서의 13ton/ha으로부터 표고 710m의 41ton/ha의 범위에 있었으며, F1, F2및 H층은 각각 5~10ton/ha, 5~11ton/ha 및 13~40ton/ha의 범위를 차지하였다.

• Journal of Forest and Environmental Science
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• 제21권1호
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• pp.75-82
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• 2005

이 시험 연구는 울폐된 천연활엽수림 내에 수하식재한 2-2 잣나무 묘목의 생육 성적을 평가하기 위하여 실시되었다. 식재 후 7년 동안의 생존률과 생장율에 대하여 상층 임관의 효과가 평가되었다. 7년생 잣나무 치수의 활착율은 약 80%로 조사되었으며, 평균 수고는 0.9m, 최소치는 0.3m, 최고치는 2.1m로 측정되었고, 평균 근원경은 1.7cm, 최소치는 l.4cm, 최고치는 3.5cm로 조사되었다. 개벌 후, 인공 조림한 잣나무의 생육 상황과 비교해 볼 때, 이 시험에서 수하식재된 잣나무 치수의 생육 상황은 공한지 인공 조림목에 비해서 매우 열등하여, 수고는 약 30%, 직경은 약 20%에도 미치지 못하는 것으로 파악되었다. 내음성이 있는 잣나무 치수라 할지라도 정상 생육하기에 상층의 울폐도가 너무 높다고 판단된다. 잣나무의 정상적인 생장과 발달을 위해서는 천연림 보육 작업에 준하는 벌채를 통하여 우량 활엽수를 잔존시키면서 50% 이상의 상층 임관을 열어 주어 광선 조건을 개선시켜야 할 것이다.

• 한국산림과학회지
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• 제108권1호
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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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• 제44권1호
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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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• 제6권1호
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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.

• 한국산림과학회지
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• 제89권2호
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• pp.185-197
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• 2000

안면도 지역의 산림 식생 구조와 입지조건을 파악하고 소나무림의 보존 대책 및 생태적으로 안정되고 지속가능한 산림경영과 관리방안을 수립하는데 필요한 기초 자료를 제공하고자 조사를 실시하였다. 안면도의 산림식생은 주로 침엽수로 구성되어 있으며 소나무군락(Pinus densiflora community), 곰솔군락(Pinus thunbergii community), 리기다소나무군락(Pinus rigida community), 굴참나무군락(Quercus variabilis community)으로 구분되었다. 산림 토양의 특성은 토양 산도가 pH 4.4~5.5(평균 4.9) 정도로 강산성을 나타내며 유기물함량과 전질소 등의 양료가 비교적 낮은 값을 보였다. 토성은 대부분 중식토 또는 사질식토로 비교적 견밀하여 통기성과 투수성은 다소 불량한 것으로 나타났다. 소나무림을 지속적으로 보전 하기 위해서는 개벌(皆伐)작업 후에 조림사업을 실시하기보다는 우수한 형질의 소나무가 많이 분포되어 있으므로 산벌갱신(傘代更新) 등과 같은 방법을 택하여 천연갱신을 유도하고, 아울러 유기물층의 제거를 통하여 소나무 종자의 발아를 촉진시키는 방법이 필요할 것으로 사료된다. 또한 이미 활엽수종이 우점한 지역에는 경제적 측면과 생태적 측면을 고려하여 활엽수종을 위주로 한 무육작업이 유리할 것으로 판단된다.

• Journal of Ecology and Environment
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• 제43권2호
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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.

• 한국환경과학회지
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• 제19권12호
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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.

• 한국산림과학회지
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• 제86권2호
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• pp.200-207
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• 1997

임분의 수종구성에 따른 수문의 변화와 강우차단 정도를 비교하기 위하여 경기도 광주군 서울대학교 농업생명과학대학 부속 중부연습림에서 1995년 5월부터 11윌 사이에 잣나무림, 낙엽송림 및 참나무림을 대상으로 수간류 수관통과류 및 강우차단량 등을 조사하였다. 이 기간 동안 총 강우량은 1,821mm이였으며 이 중 잣나무림에서 15.7%, 낙엽송림에서는 19.4% 그리고 참나무림에서 21.8%의 강우 차단비율을 보였다. 강우는 세임분 모두 수관통과류 형태가 가장 큰 비중을 차지하였으나 특히 잣나무림이 높게 나타났다. 수간류의 경우에는 잣나무림이나 낙엽송림 모두 1.1%의 낮은 비율을 보였지만 참나무림에서는 5%의 비율을 차지하였다. 수관통과류량 및 수간류하량은 모두 강우량과 높은 상관관계를 나타냈다.

• The Korean Journal of Ecology
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• 제19권5호
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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.