• Title/Summary/Keyword: 군상

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Seed Inflow Characteristics of the Korean Red Pine according to Harvest Type in Natural Regeneration Forests (소나무 천연갱신지의 목재수확 유형별 종자 유입 특성)

  • Junmo Chung;Sang Tae Lee;Hyun Seop Kim;Sang Hoon Chung
    • Journal of Korean Society of Forest Science
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    • v.112 no.3
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    • pp.331-339
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    • 2023
  • This study was conducted to identify seed inflow characteristics according to harvest typeand to provide basic data for developing a regeneration technology for secondary growth forests in Korean red pine (Pinus densiflora) succession forest formation by natural regeneration. Experimental sites were established by applying seed tree (single and group) and clear-cutting methods (10- 20- 30-m strip and 20- 30- 40-m patch). The seed inflow characteristics of the natural regeneration site were analyzed for 6 years from 2014. Most seeds were flowed to the regeneration stand from October to November. In years with good seed fructification, more than 80% were flowed in October. The average annual seed inflow by harvest type was highest in the seed tree area (296,000 seeds/ha/yr), followed by the 20-m patch clear-cutting area (291,000 seeds/ha/yr) and 10-m strip clear-cutting area (281,000 seeds/ha/yr). The distribution uniformity of seed inflow according to treatment was analyzed in the order of the 20-m strip clear-cutting area (52.2), 20-m patch clear-cutting area (52.9), and 10-m strip clear-cutting area (56.1). As a result, the 10-m strip and 20-m patch clear-cutting areas with relatively small harvest areas showed high seed inflow and distribution uniformity.

A Case Study of Spatial Allocation of Cut Blocks Using a Timber Harvest Simulator HARVEST (산림수확 시뮬레이터 HARVEST 응용에 의한 벌채지 공간배치 사례연구)

  • Song, Jungeun;Jang, Kwangmin;Han, Hee;Seol, Ara;Chung, Woodam;Chung, Joosang
    • Journal of Korean Society of Forest Science
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    • v.101 no.1
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    • pp.96-103
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    • 2012
  • In this study, we used HARVEST, a timber management strategy assessment tool, to evaluate alternative forest planning strategies on spatial pattern of cutting blocks. We applied the tool to the Gwangreung Experimental Forest (GEF) as a case study. The harvest schedules developed for GEF using a linear programming model was used to assess spatial patterns of cutting blocks under different management constraints. The results show that the allowable maximum harvest size largely affects the number, size, and distribution of cutting blocks. We also found that spatial dispersion methods and adjacency constraints could be used as an effective means to control spatial allocation of cutting blocks in order to meet certain forest ecosystem management goals.

상용주파 교류철도전화

  • 권영준
    • 전기의세계
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    • v.11
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    • pp.62-67
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    • 1963
  • 최근 영국, 독일, 인도, 소련, 일본의 동해도 신간선등은 모두 상용주파수 교류전화로 시공되고 있으며 영국같은 나라는 종래의 직류 1,500volt 시설을 육성하고 교류방식으로 전환하고 있는 현상이다. 그러므로 우리나라의 철도전화문제도 국제표준화된 교류 25,000volt로 시행하기에 앞서 충분한 검토가 필요할 것이므로 필자는 본고에서 철도동력의 역학적 고찰이나 일반적 "전기철도공학"의 양해사항은 생략하고 주로 상용주파수 군상교류철도전화에 대한 기술적 제원의 문제점을 순차적으로 고찰하여 보기로 한다.하여 보기로 한다.

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동극 또는 이극 전기기계 구성 방식

  • 오상세
    • 전기의세계
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    • v.15 no.1
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    • pp.22-23
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    • 1966
  • 본 연구는 두개이상의 원판형철심으로 구성된 철심에 두개 이상의 회전자계 또는 교번, 이동자계에 의한 변전전동, 발전, 전압주정방식으로서 재래의 원판형철심으로 구성된 방식과는 전연 그 원리가 다른것이다. 변압 또는 위상변환에 있어서는 원판형철심 또는 다각형철심에 권선한 두개 이상의 철심과 각계철심 수개로서 동극 또는 이극의 회로를 형성하여 다상 또는 군상을 얻을 수 있는 방법 또는 위상을 변환할 수 있는 방식이다.

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Forest community structure of aggregated retention harvest for Larix kaempferi (일본잎갈나무림 친환경벌채지의 산림군집구조)

  • HoJin Kim;JeongEun Lee;HyunSeop Kim;ChungWeon Yun
    • Korean Journal of Environmental Biology
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    • v.42 no.2
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    • pp.176-186
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    • 2024
  • This study aimed to provide ecological information by identifying the stand characteristics of Larix kaempferi forest vegetation (deforestation, forest influence, patch, forest) for aggregated retention harvest in Mt. Nambyeongsan, Pyeongchang-Gun. Data were collected using the Braun-Blanquet vegetation survey method from July 2020, with 54 quadrats analyzed for importance value, species diversity, similarity index, and detrended correspondence analysis (DCA). The results showed that vine species had a higher importance value in the deforestation area and forest influence area. Forest regions had the highest species diversity (2.419), while the forest influence area had the lowest(2.171). The similarity index was highest between the forest region and patch area (0.723), and lowest between the patch area and forest influence area (0.658), which was consistent with the DCA results. In conclusion, although species diversity temporarily showed higher values in the initial stage after aggregated retention harvest, it was difficult to assign ecologically specific meanings to these values. Long-term monitoring is therefore necessary to accumulate ecological information on aggregated retention harvests.