• Title, Summary, Keyword: heavy thinning

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Thinning Intensity for Large Diameter Trees in Korean White Pine Plantation of South Korea

  • Lee, Daesung;Seo, Yeongwan;Park, Jiyoung;Choi, Jungkee
    • Journal of Forest and Environmental Science
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    • v.33 no.1
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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.

The Three-year Effect of Thinning Intensity on Biomass in Larix kaempferi and Pinus koraiensis Plantation

  • Chhorn, Vireak;Seo, Yeongwan;Lee, Daesung;Choi, Jungkee
    • Journal of Forest and Environmental Science
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    • v.36 no.1
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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.

Bending and Compressive Strength Properties of Larix kaempferi According to Thinning Intensity (간벌강도에 따른 낙엽송의 휨 및 종압축강도성능)

  • Chong, Song-Ho;Won, Kyung-Rok;Hong, Nam-Euy;Park, Byung-Su;Lee, Kyung-Jae;Byeon, Hee-Seop
    • Journal of the Korean Wood Science and Technology
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    • v.42 no.4
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    • pp.385-392
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    • 2014
  • The purpose of this study was to determine the effects of plantation thinning on physical and mechanical properties of Larix kaempferi. Tree samples were obtained from unthinned, moderately, heavily thinned plantations where located in Kwangryung forest research stand. The effects of different thinning methods on the bending and parallel to grain compressive strengths of Larix kaempferi were explored. Average latewood ratio with various thinning treatments revealed the trend of unthinning < moderate thinning < heavy thinning treatment. Average annual ring width with various thinning treatments showed the trend of unthinning < moderate thinning or heavy thinning treatment. Average bending and parallel to grain compressive strengths with various thinning treatments revealed the trend of unthinning > moderate thinning > heavy thinning treatment. This indicates that thinning treatment reduces average bending and parallel to grain compressive strength properties.

A Basic Study for Analysis of Moving Characteristics of Thinning Slash (숲가꾸기 산물의 이동특성 분석을 위한 기초연구)

  • Jun, Kye-Won;Lee, Ho-Jin;Yeon, Gyu-Bang
    • 한국방재학회:학술대회논문집
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    • pp.719-722
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    • 2008
  • Forest management is done to keep ecological health of forest and to enhancement of its function. Nowadays, the abnormal climate and heavy rain happen frequently. Therefore, there are opinions that the thinning slash allowed in the mountain is flowed in rivers, which can influence in flood damage. This study, we grasp moving characteristics of thinning slash through field survey and achieved basic study about the effect of thinning slash on the discharge capacity of rivers and stream structure.

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The Adequacy Assessment and Growth Effects by Methods of 1st Thinning in Chamaecyparis obtusa Forest (편백림의 1차 솎아베기 방법에 따른 생장효과와 적절성 연구)

  • Park, Joon Hyung;Son, Yeong-Mo;Lee, Kwang Soo;Park, Eun Jung;Jung, Su Young
    • Journal of Korean Society of Forest Science
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    • v.108 no.3
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    • pp.349-356
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    • 2019
  • This study examines the effect of thinning in terms of changes in the growth characteristics of Chamaecyparis obtusa stands after they were thinned with varying intensity in Gochang, North Jeolla Province, Korea. Thinning was carried out in 2000 on Chamaecyparis obtusa stands (22 years old), and the stands were categorized in terms of the thinning intensity in the experiment: very heavy, heavy, medium, light, and control. The results of monitoring up to 2018 revealed that the diameter at breast height and the growth rate of individual trees after thinning had a positive correlation with the thinning intensity, whereas the stand volume showed a negative correlation. The height to diameter (H/D) ratio decreased by up to 70-80 due to the increased diameter at breast height after thinning and thereby resulted in better quality. The relative yield index right after the first thinning was between 0.75 and 0.95, which suggests the best timing for the first thinning had been missed. This study's findings are expected to serve as a basic reference in establishing the thinning system for Chamaecyparis obtusa forests.

Wall Thinning Analyses for Secondary Side Piping of Domestic NPPs Using CHECWORKS Code (CHECWORKS 코드를 이용한 국내 원전 2차계통 배관감육 해석)

  • Hwang, K.M.;Jin, T.E.;Lee, S.H.;Kim, W.S.
    • Proceedings of the KSME Conference
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    • pp.807-812
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    • 2001
  • This paper represents the wall thinning analysis results for secondary side piping of two types of domestic nuclear power plants based on the DB establishment and F AC analysis study for NPP secondary system piping. CHECWORKS code utilized in this study has been applied world widely to wall thinning analyses for secondary side piping and its reliability has also been proved. The predicted wear rates for several piping systems of a pressurized water reactor NPP are compared with those of a pressurized heavy water reactor NPP and with the measured wear rates. On the basis of comparison results of the predicted and measured wear rates, the analysis results can be effectively applied to the development of a standard thinned pipe management program targeted all domestic nuclear power plants.

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Wood Properties of Quercus acuta due to Thinning Intensity (붉가시나무의 간벌 강도에 따른 재질 특성)

  • Hong, Nam-Euy;Won, Kyung-Rok;Jung, Su-Young;Lee, Kwang-Soo;Byeon, Hee-Seop
    • Journal of the Korean Wood Science and Technology
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    • v.43 no.6
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    • pp.721-729
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    • 2015
  • Wood properties depend on not only environmental factors such as soil, climate change, or forest stand characteristics, but also silviculture practices such as thinning, regeneration, or selection. This study report influences of the extent of thinning intensity from no thinning, moderate and heavy thinning to the wood property of Quercus acuta forest stands in Wan-do arboretum, Jeollanam-do Province. The results showed that there were close relationships between thinning intensity and anatomical, physical or mechanical properties of Quercus acuta wood. Especially, there are close relationships between thinning intensity and ring width or mechanical properties of wood. As a result, this study showed high correlations between Quercus acuta wood properties and thinning intensity of Quercus acuta forest stand. These findings are expected to be very useful as fundamental data for the implementation of silviculture practices of this specie to produce timber.

Changes in Understory Vegetation of a Thinned Japanese Larch (Larix leptolepis) Plantation in Yangpyeong, Korea

  • Son, Yo-Whan;Lee, Yoon-Young;Kim, Rae-Hyun;Seo, Kyung-Won;Ban, Ji-Yeon;Seo, Kum-Young;Koo, Jin-Woo;Kyung, Ji-Hyun;Noh, Nam-Jin
    • The Korean Journal of Ecology
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    • v.27 no.6
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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.

Thinning Intensity and Growth Response in a Quercus acuta Stand (붉가시나무림의 솎아베기 강도에 따른 생장 반응 효과)

  • Jung, Su Young;Ju, Nam Gyu;Lee, Kwang Soo;Yoo, Byung Oh;Park, Yong Bae;Yoo, Seok Bong;Park, Joon Hyung
    • Journal of Korean Society of Forest Science
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    • v.104 no.4
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    • pp.536-542
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    • 2015
  • This study was examined for the growth response of tree diameter and volume to thinning treatments from different thinning intensities using three long-term thinning trials for Japanese Evergreen Oak (Quercus acuta Thunb.) stands in Wando island, Korea. After thinning in 1999, annual tree growth of diameter and volume was highest in heavy thinned stands for individual tree and this growth pattern of thinning response showed similar tendency to the individual tree growth response in light thinned stands. By increasing diameter growth, the value of H/D ratio (HDR) as an indicator of stem form was properly decreased and improved up to 80%. Although there is significant growth response of basal area in both heavily and lightly thinned stands, the growth potential both of heavily and lightly thinned stands in total stand volume is not likely to reach at the level of unthinned stands because of basal area growth loss associated with both light and heavy thinnings.

Soil CO2 Efflux by Thinning Treatments of a Black Pine (Pinus thunbergii Parl.) Stand Disturbed by Pine Wilt Disease (소나무재선충병 발생 곰솔임분의 간벌에 따른 토양 호흡 동태)

  • Choi, Eun-Jin;Seo, Huiyeong;Lee, Kwang-Soo;Yoo, Byung-Oh;Kim, Choonsig;Cho, Hyun-Seo
    • Journal of Korean Society of Forest Science
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    • v.105 no.1
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    • pp.12-18
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    • 2016
  • This study was carried out to investigate the change on soil $CO_2$ efflux rates, soil temperature, soil water content and soil pH by thinning intensity treatments (heavy thinning, light thinning, control) of a black pine (Pinus thunbergii Parl.) stand disturbed by pine wilt disease in Wola National Experimental Forests in Jinju, Gyeongnam province. Monthly variations of soil $CO_2$ efflux rates were not significantly different between the thinning and the control treatments (P>0.05). The annual mean soil $CO_2$ efflux rates were $0.58g\;CO_2m^{-2}h^{-1}$ for the light thinning, $0.49g\;CO_2m^{-2}h^{-1}$ for the heavy thinning and $0.45g\;CO_2m^{-2}h^{-1}$ for the control treatments, respectively. There was a significant exponential relation between soil $CO_2$ efflux rates and soil temperature, but no correlation between soil water content or soil pH and soil $CO_2$ efflux rates. The values of $Q_{10}$ were 3.40 for the light thinning, 3.20 for the heavy thinning and 3.06 for the control treatments, respectively. The results indicate that soil $CO_2$ efflux rates in a black pine stand disturbed by pine wilt disease could be affected by thinning treatments.