• 제목/요약/키워드: TREE GROWTH INCREMENT

검색결과 68건 처리시간 0.031초

직류 전계하 LLDPE/EVA혼합필름의 절연파괴특성 (Breakdown Characteristics of LLDPE/EVA mixture film under DC field)

  • 고시현;김형주;이종필;신현택;이충호;홍진웅
    • 한국항해항만학회:학술대회논문집
    • /
    • 한국항해항만학회 2000년도 추계학술대회논문집
    • /
    • pp.65-68
    • /
    • 2000
  • Polyethylene, has long history and is widely used, was researched due to good electrical properties by many authors. But PE under stress has the critical defects of space charge accumulation and tree growth, so various methods such as catalyst, additives and blend to improve these problems have been execute, of which we selected blending method. As in our previous papers we investigated electrical conduction, dielectric and AC dielectric breakdown characteristics, we did DC dielectric breakdown characteristics in this paper. We selected pure LLDPE, pure EVA and LLDPE films mixed with EVA as specimens, which were mixed with the weight percentages of 50, 60, 70 and 80[wt%] to be thin film. DC applying voltage speed was 500[V/sec]. The relation between dielectric breakdown characteristics and the variations of super structure due to mixing was investigated, and especially trap level at amorphous region, threshold energy increment of conductive electron at free volume were considered.

  • PDF

직류 전계하 LLDPE/EVA혼합필름의 절연파괴특성

  • 고시현;김형주;이종필;신현택;이충호;홍진웅
    • 한국전기전자재료학회:학술대회논문집
    • /
    • 한국전기전자재료학회 2000년도 추계학술대회 논문집
    • /
    • pp.65-68
    • /
    • 2000
  • Polyethylene, has long history and is widely used, was researched due to good electrical properties by many authors. But PE under stress has the critical defects of space charge accumulation and tree growth, so various methods such as catalyst, additives and blend to improve these problems have been execute, of which we selected blending method. As in our previous papers we investigated electrical conduction, dielectric and AC dielectric breakdown characteristics, we did DC dielectric breakdown characteristics in this paper. We selected pure LLDPE, pure EVA and LLDPE films mixed with EVA as specimens, which were mixed with the weight percentages of 50, 60, 70 and 80[wt%] to be thin film. DC applying voltage speed was 500[V/sec]. The relation between dielectric breakdown characteristics and the variations of super structure due to mixing was investigated, and especially trap level at amorphous region, threshold energy increment of conductive electron at free volume were considered.

  • PDF

大氣汚染地域 適應 樹種 選拔에 關한 硏究 (A Study on the Selection of Adaptable Tree in Air Pollution Area)

  • 朴晥澈
    • 한국대기환경학회지
    • /
    • 제7권1호
    • /
    • pp.55-65
    • /
    • 1991
  • The study was performed to select a adaptable tree species under stressed field conditions where there are a industrial plants operating with a number of smoke stacks emitting pollutants, such as hydrogen fluoride and sulfur dioxide. As a result of the study, a tree species selected are due to construct a forest belt in a zones near industrial plants to reduce the concentrations of air pollutants. The concentrations of atmospheric hydrogen fluoride and sulfur dioxide were very higher at experimental sites near industrial plants (air-pollution sites) than at control site. The leaves of 7 tree species grown at air pollution sites contained more sulfur and, specially, fluorine than at those control site. Among the tested tree species, Ligustrum japonicum Thunb. and Euonymus japonica Thunb. grown at air pollution sites did not at all break out a foliar injury but appeared to be healthy, as well as those grown at control site. Acer pseudo-sieboldianum Kom., Pinus virginiana Mill., Larix leptolepis Gordon., Pinus koraiensis Sieb. et Zucc., Pinus strobus L., Picea abies Karst and Ligustrum obtusifolium Sieb. et Zucc., however, showed a severe fluoride-type foliar injury such as necrosis on tip or margin of leaves, etc. Fluorine found in leaves was proved to be correlated to sulfur found in leaves whereas index of foliar injury hadn't a good correlation to pollutants found in leaves. It appears that Euonymus japonica Thunb., Ligustrum japonica Thunb., Platanus acerifolia Willd, Chamaecyparis pisifera Endl., Populus tomentiglandulosa T. Lee and Sophora japonica L. grown at both experimental sites had a high value of percent survival whereas Pinus virginiana Mill., Pinus koraiensis Sib. et Zucc., Koelreuteria paniculata Laxm. and Alnus hirsuta Rupr. had an extremely low value of that. In comparison with control site, the percent tree height increments in Chamaecyparis pisifera Endl., Ligustrum japonicum Thunb., Quercus acutissima Carruth., Populus tomentiglandulosa T. Lee, Pinus thunbergii Parl and Euonymus japonica Thunb. and the percent upmost root diameters in Populus tomentiglandulosa T. Lee, Chamaecyparis pisifera Endl., Euonymus japonica Thunb., Ligustrum japonicum Thunb., Betula platyphylla var. japonica Hara and Pinus thunbergii Parl. cultivated at air polluted sites showed very high value above 90%, respectively. A significant negative correlation (r=-0.662) was recognized between the index of foliage injury and the percent collective character, which was the mean of tree characters such as percent survival, percent tree height increment and percent upmost root diameter increment which compared to those at air polluted site with those at control site. Based on the percent collective character Ligustrum japonicum Thunb., Euonymus japonica Thunb., Chamaecyparis pisifera Endl., Populus tomentiglandlosa T. Lee, Betula platyphyla var. japonica Hara and Platanus occidentalis L. have large value about 90%, respectively. Therefore, the results indicate that this tree species are adaptable species in air polluted regions. For better understanding of the adaptable tree species, furthur studies concerning the effects of various air pollutants on the tree growth are required.

  • PDF

SCB액비처리에 따른 밤나무 생장 및 결실특성 (The Characteristics of Growth and Fruiting in Chestnut Trees by SCB (Slurry Composting and Biofiltration) Liquid Fertilizer)

  • 권용희;이욱;황석인;백을선
    • 한국산림과학회지
    • /
    • 제98권6호
    • /
    • pp.676-680
    • /
    • 2009
  • 저농도 SCB(Slurry Composting Biofiltration)액비 시비가 생장 및 결실특성에 미치는 영향을 알아보고자 접목 7년생 '축파(Tsukuba)' 품종을 대상으로 SCB액비, 화학비료, 유기질비료, 무처리구 등 4처리를 관행 시비량에 준한 시비 처리로 2008년부터 2009년까지 2년간 생장 및 결실특성을 각각 조사하였다. 수고 및 근부직경의 생장은 전년도에 비해 화학비료와 SCB액비 처리구에서 각각 8.18%와 26.93%, 8.04%와 25.90%의 증가량을 보였으며, 착구부 직경에 대한 기부직경의 비는 화학비료 처리구를 제외하고 전년도에 비해 모든 처리구에서 감소되었다. SCB액비 처리구에서 착과율이 86.25%로 높게 나타남에 따라 SCB액비가 생장과 수세에 기여하는 양료 역할을 하는 것으로 판단되며 새로운 비종으로서 대체 효과가 있는 것으로 나타났다.

레지스토그래피를 이용한 수령조사 가능성 검토 (Verifying the Possibility of Investigating Tree Ages Using Resistograph)

  • Oh, Jung-ae;Seo, Jeong-Wook;Kim, Byung-Ro
    • Journal of the Korean Wood Science and Technology
    • /
    • 제47권1호
    • /
    • pp.90-100
    • /
    • 2019
  • 본 연구는 수목의 수령을 조사하는 방법으로 레지스토그래피를 활용하는데 있어서 수종별로 가장 적합한 삽입속도를 찾기 위하여 수행되었다. 회전속도는 1,500 r/min로 고정하였다. 수종은 낙엽송, 더글라스 퍼, 잣나무, 전나무, 느티나무이다. 실험결과 수종에 따른 적합한 삽입속도는 느티나무 75 cm/min, 낙엽송과 더글라스 퍼 100 cm/min, 전나무 150 cm/min, 잣나무 175 cm/min으로 나타났다. 하지만 모든 경우에서 연륜폭이 1 mm이하일 경우 연륜경계 확인이 어려운 것으로 확인되었다. 연륜폭이 1 mm이하인 경우를 제외하고는 연륜폭측정기와 레지스토그래피의 연륜폭그래프는 매우 일치하였다. 향후 연륜폭이 1mm 이하인 미세연륜 확인이 가능한 레지스토그래피가 개발된다면 레지스토그래피가 수령조사를 위해 전통적으로 활용되는 생장편의 연륜관찰방법을 대체할 수 있을 것이다. 또한 레지스토그래피의 연륜폭그래프는 생장량 조사에도 활용할 수 있을 것으로 판단된다.

소나무 모수림 시업지의 임분구조 및 치수생육특성 (Stand Structure and Sapling Growth Characteristics of Korean Red Pine Stands Regenerated by the Seed Tree Method)

  • 이대성;최정기
    • 한국산림과학회지
    • /
    • 제110권4호
    • /
    • pp.678-688
    • /
    • 2021
  • 본 연구는 소나무 모수작업에 따른 천연갱신 조성방안 및 산림시업지침을 마련할 수 있도록 2001년 실시된 소나무 천연하종갱신 시업지를 대상으로 작업 후 18년이 경과한 시기에 표준지조사를 실시하고 임분현황 및 치수생육상태를 분석하여 생장특성 및 임분자료를 제공하고자 하였다. 연구대상지는 강원도 춘천시 동산면 원창리 내 강원대학교 학술림에 위치하고 있으며, 설치된 모수시험림에서 2018년 11월 조사된 흉고직경, 수고, 수관급, 수간형질, 수령, 수고생장량 등의 자료를 활용하였다. 분석 시 흉고단면적, 재적, 형상비와 더불어 임분상대밀도, 임목축적도 등의 추가인자를 산출하여 시업지의 현황을 분석하였다. 잔존모수는 58본/ha으로 임목축적도 17.7%이었으며, 치수는 2,330본/ha으로 임목축적도 79.0%로 진단되었다. 치수의 수령은 2001~2007년에 발아분포를 보이고 있었는데 대부분은 15~16년생에 속하였다. 치수 생육상태는 흉고직경 10 cm, 수고 8 m로 파악되었다. 수관급이 우세할수록 흉고직경과 수고가 더 크게 나타났으며, 분산분석 및 Duncan 다중비교검정에서도 수관급별 차이는 통계적으로 매우 유의하였다(p<0.0001). 형상비는 80~90% 범위에 많이 분포하였으며, 95%이상 대부분 치수의 형질은 수간이 곧고 분지가 없으며, 초두부가 부러지지 않고 병해충의 피해가 없는 양질의 형태로 파악되었다. 치수의 평균 연년수고생장량은 1년생 21.9 cm, 5년생 43.3 cm, 10년생 54.3 cm, 15년생 64.3 cm이었으며, 전체적으로 수령증가에 따라 생장량이 우상향하는 것으로 나타났다. 공분산분석 결과, 수관급별 연년수고생장량에서도 유의적인 차이가 나타났으며, 회귀분석의 파라미터 추정치는 수령이 증가하거나 수관급이 우세할수록 연년수고생장량이 높은 것으로 분석되었다.

Growth Analysis of Red Pine (Pinus densiflora) by Stem Analysis in the Eastern Region of Korea

  • Seo, Yeongwan;Lee, Daesung;Choi, Jungkee
    • Journal of Forest and Environmental Science
    • /
    • 제31권1호
    • /
    • pp.47-54
    • /
    • 2015
  • The study was performed to analyze the growth of the red pine (Pinus densiflora) in the Eastern Region of Korea. Stem profile data from a total of 8 dominant trees of which each tree represents its site were collected and used for the analysis. The stem volumes were calculated using Smalian's formula and much higher than the ones by Korea Forest Research Institute in larger than dbh 40 cm. The total bark volumes were more proportionally related to dbh and stem volume than to height and age. The bark thickness and volume decreased as relative height increases but increased as relative dbh increased. The average PAI of dbh and height reached the highest at 0.8 cm/yr (age 15) and at 0.45 m/yr (age 30) respectively, while the average PAI of volume steadily tended to increase up to age 80. The growth percentages of dbh, height and volume tended to decrease with age and volume growth percentage was higher than dbh and height.

Damages of Young Persimmon Tree as Affected by Application of Immature Liquid Pig Manure

  • Choi, Seong-Tae;Park, Yeo-Ok;Ahn, Gwang-Hwan;Kim, Eun-Gyeong;Son, Ji-Young;Joung, Wan-Kyu;Hong, Kwang-Pyo
    • 한국환경농학회지
    • /
    • 제38권2호
    • /
    • pp.89-95
    • /
    • 2019
  • BACKGROUND: Liquid pig manure (LPM) has been used as an alternative for conventional fertilizers on some gramineous crops. However, its chemical properties varied widely depending on the degree of the digestion. A pot experiment was conducted to determine the responses of persimmon trees to immature (not well-digested) LPM application. METHODS AND RESULTS: Ten application levels of immature LPM, consisted of a total of 3 to 30 L in 3-L increment, were applied during summer to 5-year-old 'Fuyu' trees grown in 50-L pots. Increasing the LPM application rate caused defoliation, wilting, and chlorosis in leaves. When applied with the rate of 3 L during summer, the tree produced small fruits with low soluble solids and bore few flower buds the following season, indicating insufficient nutritional status. In trees applied with the LPM rates of 6~12 L, both fruit characteristics and above-ground growth of the trees appeared normal but some roots were injured. However, application of higher LPM rates than 27 L resulted in small size, poor coloration, or flesh softening of the fruits the current season. Furthermore, the high LPM rates caused severe cold injury in shoots during winter and weak shoot growth the following season. It was noted that the application of higher LPM rate than 9 L damaged the root, even though above-ground parts of the tree appeared to grow normally. CONCLUSION: The results indicated that an excessive immature LPM application could cause various injuries on leaves, fruits, and the roots in both the current and the following season.

Comparison of stand structure and growth characteristics between Korean white pine plantation and oak-dominated natural deciduous forest by thinning treatment

  • Lee, Daesung;Choi, Jungkee
    • Journal of Ecology and Environment
    • /
    • 제46권1호
    • /
    • pp.85-98
    • /
    • 2022
  • Background: Korean white pine (Pinus koraiensis) is a major commercial species, and the importance of the oak trees (Quercus spp.) is increasing due to various factors such as environmental and ecological values. However, more information is required to clearly understand the growth characteristics of these species especially regarding thinning intensity. This study was performed to provide the basic information to develop the silvicultural guideline and field manual by analyzing tree and stand characteristics in line with thinning intensity in the Korean white pine plantation and oak-dominated natural deciduous forest. Results: Diameter at breast height (DBH) and volume changes by the thinning intensity in the Korean white pine plantation were significantly different from those in the oak-dominated deciduous natural forest. In particular, DBH distribution in the pine stand appeared that there were more large diameter trees as the thinning intensity was higher. DBH periodic annual increment (PAI) of the pine stand was higher as the thinning intensity was stronger and the growth period was shorter. This trend was similarly shown in the natural deciduous forest, but the amount of PAI was smaller than in pine stand. The volume PAI after thinning was not decreased over time. In each stand type, the PAI tended to be lower as stand density was higher. The volume PAI in the pine stand was significantly higher than that in the oak-dominated natural deciduous forest. Dead trees occurred the most in the unthinned plots of each stand type, and those were higher in the natural deciduous forest. Ingrowth trees were observed only in the natural deciduous forest, and its distribution was the lowest in unthinned plots; Korean white pine as ingrowth occurred the most frequently among many tree species. Conclusions: Different effects of thinning treatment on DBH and volume PAI, mortality, and ingrowth were observed for each stand. With respect to forest growth, Korean white pine plantation was superior to the oak-dominated natural deciduous forest. The results of this study offer fundamental information for the development of silvicultural guidelines for Korean white pine plantations and oak-dominated natural deciduous forests in Korea.

설악산 잣나무(Pinus koraiensis) 천연림의 해발고별 임분구조 및 생장특성 (Stand Structure and Growth Characteristics at Different Elevations of the Korean Pine(Pinus koraiensis) Natural Forest on Mt. Seorak)

  • 김현섭;배상원;장석창;정준모
    • Journal of Forest and Environmental Science
    • /
    • 제27권3호
    • /
    • pp.157-167
    • /
    • 2011
  • This study was conducted to analyze the stand structure and growth characteristics along different elevations of Pinus koraiensis natural forests located at mean elevation 1,300 m (site1), 900 m (site2) and 600 m (site3) on Mt. Seorak. Mean DBH and height of P. koraiensis were 25.4 cm and 12.3 m in site1, while that of site2 and 3 were over 40 cm and 20 m, respectively. For this reason, there was 5 times difference of single tree volume between site1 and other sites(p<0.05). Mean ringwidth increment of P. koraiensis was 1.1 mm/yr in site1, 1.5 mm/yr in site2 and 2.6 mm/yr in site3. However, recent growth of ringwidth has increased by 8.6% in site1, whereas site2 and 3 have fallen by approximately 50% over the last 10 years. These results signify that the growth and distribution of natural P. koraiensis are effected by different climatic environment along elevations.