• Journal of Forest and Environmental Science
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• 제33권1호
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• pp.74-77
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• 2017

The purpose of this study is to analyze the effect of thinning intensity on the growth of large diameter trees in Korean white pine (Pinus koraiensis S. et Z.) plantation. Eight thinning plots were analyzed by categorizing into heavy thinning, light thinning, no thinning (control) according to thinning intensity. As a result, average DBH increased more in heavy thinning plots than in light thinning or unthinned plots. The number of large trees (DBH>25 cm) were obviously shown the most in heavy thinning plots. It is considered that heavy thinning is needed for the production of the large diameter trees.

• Journal of Forest and Environmental Science
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• 제36권1호
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• pp.17-24
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• 2020

This study aimed to figure out and compare the increment of biomass by thinning intensity focused on the plantation of the two major coniferous species (Larix kaempferi and Pinus koraiensis) of South Korea. The inventory interval was three years under the effects of three types of thinning treatments; control (no thinning), light (20% thinning) and heavy (40% thinning). The results showed standing biomass increment of both species decreased as thinning intensity increased (heavylight>control). Meanwhile, the lowest of on-site biomass changes occurred in the control plot, and the greatest was in the heavy thinning plot because thinning was involved with leaving the felling residual biomass (leaves, branches and roots) on the site. According to the results from this short-term study, unthinned stands is preferable for maximizing standing biomass as well as carbon sequestration. However long-term investigation should be considered in order to see more clear results.

• 한국환경농학회지
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• 제42권2호
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• pp.104-111
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• 2023

As apple trees mature, it is important to maintain good light distribution within the canopy to produce marketable fruits. Tree thinning is the selective removal of a proportion of trees growing in the orchard to provide more growing space and a good light environment for the remaining trees. This study was conducted over 3 years (14-16 years after planting) to investigate the influence of tree thinning on vegetative growth, yield, fruit quality, and blooming in the 14 years old slender spindle 'Fuji'/M.9 apple trees planted with the tree space of 3.2×1.2 m. The trees were placed in a control group (no thinning; 260 trees per 10 a) or a tree thinning group (thinned 50% of the control; 130 trees per 10 a). The tree thinning successfully improved light penetration, yield per tree, fruit red color, and yield efficiency for 3 years, and the tree thinning controlled the occurrence of biennial bearing. However, tree thinning significantly decreased accumulated yield per 10 a compared with the control. The vegetative growth, yield per tree, soluble solid contents, and blooming were not clear by the occurrence of biennial bearing in the control. These results indicated that tree thinning was a good method for improving light penetration and preventing biennial bearing in the old 'Fuji'/M.9 high-density apple orchards.

• 생물환경조절학회지
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• 제12권1호
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• pp.17-21
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• 2003

참외재배시 저광도 조건시 상품수량의 급격한 저하를 막기 위하여 본 연구가 수행되었다. 과실 비대기에 해당되는 착과후 10일부터 400 $\mu$mol$.$m$^{-}$2$.$S$^{-1}$정도의 저광도 조건이 지속되면 광합성 속도도 떨어지고, 엽록소 함량도 낮았으며 특히 요소 무엽면시비구의 광합성속도는 크게 저하되었다 당도에 있어서는 자연광에 비해 저광도 처리구가 전반적으로 낮았는데, 착과수가 많고 무엽면시비구일수록 낮았다. 발효과 발생률은 요소 엽면시비 유무에 관계없이 자연광에서는 4% 미만으로 발생되었는데, 저광도 조건에서는 10% 이상 발생되었다. 특히 저광도 조건에서 적과수를 적게 한 처리구일수록 발효과 발생률이 높았는데, 적과를 하지 않은 처리구는 각각 39와 48%로 매우 높은 발생율을 보였다. 수확시기 지연은 요소 엽면시비 유무와 관계없이 자연광에 비해 저광도 조건에서 늦어지는 경향을 보였는데, 적과수가 적을수록 지연정도는 심했다 주당 상품수량에 있어서는 저광도 조건하에서 자연광에 비해 16∼34% 수준 정도로 매우 낮은 수량을 보였는데, 요소 0.5% 액을 엽면시비하고 2개를 적과한 처리구가 34%수준으로 자연광에 비해 다른 처리보다 높은 상품수량을 보였다. 따라서 참외재배시 과실 착과후 10일경부터 강우 등에 의해 장기간 저광도 조건이 지속될 것으로 전망되면 상품수량의 급격한 저하를 막기 위하여 주당 6개의 착과 과실중에서 2개를 적과하고, 요소 0.5%액을 2회 정도 엽면시비 해주는 것이 바람직 할 것으로 사료된다.

• Journal of Ecology and Environment
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• 제34권4호
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• pp.347-355
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• 2011

Effects of forest thinning on community level properties have not been understood yet in Korea. We investigated regeneration patterns and trajectories after a disturbance by applying a chronosequence approach. Light availability, litter and woody debris cover, and species composition were determined for twenty 50 m line-transect samples representing a disturbance duration gradient (within 11 years). Environmental factors such as light availability and coverage of woody debris and litter changed abruptly after thinning and then returned to the pre-disturbance state. Although species richness was gained at shrub and ground layer in a limited way in both forests, cover of various functional types revealed diversity in their responses. Notably, Alnus firma stands exhibited a larger increment of cover in woody plants. Ordination analysis revealed different regeneration trajectories between natural and planted stands. Based on ordination analysis, rehabilitated stands showed movement to alternative states compared with natural ones, reflecting lower resilience to perturbation (i.e., lower stability). Our results suggest that community resilience to artificial thinning depends on properties of the dominant species. But to get more explanatory ecological information, longer-term static observations are required.

• Archives of Plastic Surgery
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• 제44권2호
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• pp.157-161
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• 2017

Background Thin hairs are critical to achieve natural result in female hairline correction surgery. However, there are few studies on the usefulness of hair thinning by intense pulsed light (IPL) after hairline correction surgery in East Asian females. Methods Hair thinning using IPL was performed in 54 women who had complained about thick hairs along the frontal hairline after hairline correction surgery. Patient mean age was 31.2 years old and patients were an average of 2.1 years post-hairline correction surgery. Initial treatment used 10 J, while second and third sessions were conducted with 10 to 15 J according to responsiveness to treatment. Results Mean thickness of individual hairs assessed before the procedure was $78.86{\mu}m$. The mean number of procedures was 1.6 per patient. Forty of 54 subjects (74%) achieved satisfactory hair thinning with only one procedure from 78.01 to $66.14{\mu}m$ after treatment. The measured thickness was $66.43{\mu}m$ at the end of the first year in patients who were satisfied after one procedure. Thirteen cases achieved satisfactory hair thinning after two sessions. Mean thickness was $74.44{\mu}m$ and $67.51{\mu}m$, before and after the second session. One case required a third session with 15J, thinning from 89.00 to $66.50{\mu}m$. Conclusions Hair thinning by IPL is a very useful method to provide a natural look after hairline correction surgery in East Asians, who have naturally thick hair.

• Journal of Ecology and Environment
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• 제48권2호
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• pp.137-143
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• 2024

Background: The study was carried out to analyze the temporal changes of trade-offs (TOs) between two ecosystem services (ESs) before and after thinning in a Pinus koraiensis plantation on Mt. Gari from 2006 to 2021. As target variables, aboveground carbon (AGC) storage and species richness (SR) were chosen for regulating and supporting services. Thinning was applied from 2007 through 2008 with three treatments: 1) light thinning (LT), 2) heavy thinning (HT), and 3) control (Con). Results: Thinning influenced both AGC and SR. In 2021, AGC in the Con (111.1 t C ha^-1) was significantly higher compared to the LT (82.0 t C ha^-1) and HT (60.4 t C ha^-1) after thinning from 2007 to 2008. Also, SR was marginally higher in the LT (94 species) than in the Con (55 species) and HT (87 species) in 2011. Relative benefits of AGC and SR showed similar trends with the obtained values. In addition, the effects of thinning on TO varied among treatments and over time, demonstrating different degrees of TO between the two ESs. In the LT, TO was 0.13 in 2006 and slightly increased to 0.2 by 2021. TO in the HT exhibited a relatively rapid increase from 0.22 in 2006 to 0.58 by 2021, while To in the Con fluctuated, rising to 0.36 in 2011 from 0.1 in 2006 and decreasing to 0.25 by 2021. Among the three treatments, the degree of TOs between the two ESs was the lowest in the LT. Conclusions: Depending on thinning intensities, the responses of ESs and the degree of TOs vary. Regarding the balance between enhancements and TOs in ESs among treatments, the LT treatment showing intermediate carbon storage, higher SR, and lower TOs will be a proper silvicultural application.

• The Korean Journal of Ecology
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• 제27권6호
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• pp.363-367
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• 2004

Photosynthetically active radiation (PAR) beneath the forest canopy, understory species richness and diversity, and biomass were measured in a Larix leptolepis plantation seven years after thinning in Yangpyeong. Four different thinning intensities (control, $10\%,\;20\%\;and\;40\%$ stocking reduction) were applied in 1997. The current PAR values were lower than those measured four years after thinning, and PAR at the heavy thinning plots was significantly higher than that of other thinning intensities. A total of 23 species including 9 tall-trees and 14 shrubs were found for the high layer while a total of 82 species including 10 tall-trees, 29 shrubs, and 43 herbs for the low layer. Species richness and diversity generally increased with thinning intensities, and the trends were more evident for the low layer. Aboveground biomass significantly differed among thinning intensities for both shrubs and herbs. Also there was a negative correlation between biomass and the current number of stems per hectare. The current study suggested that the effects of thinning on light conditions at the forest floor, species richness and diversity and production of understory vegetation continued seven years after the treatment.

• 한국산림과학회지
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• 제99권3호
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• pp.397-403
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• 2010

본 연구는 서로 다른 강도로 간벌 시행 후 4년이 경과한 경기도 광릉시험림 내 46년생 잣나무(Pinus koraiensis Siebold et Zuccarini) 인공림에서 간벌 강도가 토양 온도, 수분, 광 유효도(photosynthetically active radiation, PAR) 및 직경 생장량 변화에 미치는 초기 영향에 대하여 알아보고자 수행되었다. 간벌은 2004년 흉고단면적($m^2$/ha)을 기준으로 45%(T45)와 60%(T60)를 제거하는 방법으로 실시되었다. 대조구, T45 및 T60의 평균 토양 온도는 각각 8.9, 10.0, $10.2^{\circ}C$, 평균 토양 수분 함량은 14.3, 16.1, 16.1%이었으며, 평균 토양 온도는 대조구 포함 각 처리구 사이에서, 평균 토양 수분 함량은 대조구와 간벌 처리구간 통계적으로 그 차이가 인정되었다(p<0.05). 대조구, T45 및 T60의 평균 PAR는 각각 44, 143, 178 ${\mu}mol/m^2$/sec로 나타나 각 처리구 간 통계적으로 유의한 차이가 인정되었다(p<0.05). 간벌 후 4년간 측정한 연평균 직경 생장량은 대조구, T45 및 T60에서 각각 0.4, 1.5, 1.2 mm으로 조사되어 간벌 처리구가 대조구에 비해 직경 생장량이 높았다. 결론적으로 간벌 후 4년이 경과한 시점에서도 토양 온도, 수분 및 임분 내 유입되는 광 유효도는 지속적으로 간벌에 의해 영향을 받는 것으로 나타났다.

• 인간식물환경학회지
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• 제24권6호
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• pp.629-638
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• 2021

Background and objective: This study was conducted to develop diameter growth models for thinned Quercus glauca Thunb. (QGT) stands to inform production goals for treatment and provide the information necessary for the systematic management of this stands. Methods: This study was conducted on QGT stands, of which initial thinning was completed in 2013 to develop a treatment system. To analyze the tree growth and trait response for each thinning treatment, forestry surveys were conducted in 2014 and 2021, and a one-way analysis of variance (ANOVA) was executed. In addition, non-linear least squares regression of the PROC NLIN procedure was used to develop an optimal diameter growth model. Results: Based on growth and trait analyses, the height and height-to-diameter (H/D) ratio were not different according to treatment plot (p > .05). For the diameter of basal height (DBH), the heavy thinning (HT) treatment plot was significantly larger than the control plot (p < .05). As a result of the development of diameter growth models by treatment plot, the mean squared error (MSE) of the Gompertz polymorphic equation (control: 2.2381, light thinning: 0.8478, and heavy thinning: 0.8679) was the lowest in all treatment plots, and the Shapiro-Wilk statistic was found to follow a normal distribution (p > .95), so it was selected as an equation fit for the diameter growth model. Conclusion: The findings of this study provide basic data for the systematic management of Quercus glauca Thunb. stands. It is necessary to construct permanent sample plots (PSP) that consider stand status, location conditions, and climatic environments.