• Title/Summary/Keyword: tree fall

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Gap formation and susceptible Abies trees to windthrow in the forests of Odaesan National Park

  • Jeon, Mina;Lee, Kyungeun;Choung, Yeonsook
    • Journal of Ecology and Environment
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    • v.38 no.2
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    • pp.175-183
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    • 2015
  • Extremely strong winds and heavy rainfall caused canopy gaps in a mixed Abies holophylla broadleaf forest and a Quercus mongolica-dominated forest in Odaesan National Park, Korea in October 2006. The impact of the combination of strong winds and torrential rain on the development of forest gaps and canopy structures were investigated. The mean size of newly created gaps were $205m^2$ in the mixed forest and $86m^2$ in the Quercus forest, and were created by 2.8 and 1.4 gapmaker trees, respectively. Among the 73 trees lost in the mixed forest, 59% succumbed because of direct wind damage while 41% were struck by neighboring trees that fell into them. Most of these trees downed by wind were uprooted (74%), while the trees downed by neighboring tree falls snapped (78%). 21 trees in the Quercus forest died from direct wind damage, and 57% of them were uprooted. Although the relative density of Abies nephrolepis and A. holophylla represented only 0.2% and 6.4%, respectively, of all species in the intact mixed forest, they accounted for 27% and 15%, respectively, of all trees affected by wind on that site. In fact, 85% of the total A. nephrolepis and 91% of the total A. holophylla in the mixed forest fell directly due to strong wind. By contrast, only one Abies species, A. nephrolepis, was found in the Quercusdominated forest, and it accounted for 7.3% of the species composition. These findings suggest that A. nephrolepis and A. holophylla are particularly susceptible to high winds because of their great heights and shallow root systems.

Production of Mass and Nutrient Content of Decaying Boles in Mature Deciduous Forest in Kwangnung Experimental Forest Station, Korea

  • You, Young-Han;Kim, Joon-Ho
    • The Korean Journal of Ecology
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    • v.25 no.4
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    • pp.261-265
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    • 2002
  • In order to elucidate the characteristics of standing crop biomass, production and nutrient content of dead bole in mature ecosystem, we surveyed the dynamics of decaying bole of old-aged deciduous forest in 1993 and 2002 in Kwangnung Experimetal Forest Station. In addition, we and estimated annual bole production, water content, wood density and nutrient content and compared the results with that of temperate ecosystem. Total dead wood biomass was estimated to be 5.6ton/ha in 1993 and 17.6 ton/ha in 2002. Standing dead tree accounted for a total of 1.1 ton/ha in 1993 and 4.8 ton/ha in 2002, which was 20% and 27$\%$ of the sum of dead bole mass in 1993 and 2002, respectively. Annual production of bole biomass was 1.3 ton/ha/yr. These values fall into the low range of dead wood biomass for the mature temperate ecosystems. Tree species composing standing bole was mainly Quercus and Carpinus trees. This bole species composition resembles alive species composition of this forest. Water content of bole increased as positive logarithmically, but wood density of bole decreased as negative exponentially along with the progress of decay. N, P, Ca and Mg concentrations in decaying boles generally increased with decay, except for K. Annual nutrient input via dead bole is 1.6 kg/ha/yr for N, 0.04 kg/ha/yr for P, 1.0 kg/ha/yr for K, 1.7 kg/ha/yr for Ca and 0.3 kg/ha/yr for Mg, respectively.

Reconstruction of May~June Precipitation (253 Years: A.D. 1746~1998) in East-Coastal Region (Yungdong) of Korea from Tree Rings of Pinus densiflora S. et Z. (소나무 연륜연대기를 이용한 영동지방의 5~6월 강수량 (253년간: A.D. 1746~1998) 복원)

  • 박원규;서정욱
    • The Korean Journal of Quaternary Research
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    • v.14 no.2
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    • pp.87-99
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    • 2000
  • May-June precipitation (253 years : A.D. 1746∼1998) of Yungdong region (coastal area of East-central Korea) was reconstructed using two tree-ring chronologies of Pinus densiflora sampled from Daeseung Fall area in Sorak Mountains. Dry periods were 1765∼1800 (longest dry period), 1835∼1845, 1890∼1910, 1920∼1940 and 1980∼1995, and wet ones 1810∼1830, 1850∼1890 and 1950∼1970. In long-term variation, late 18th century was dry. The 19th century May-June (250㎜) was wetter than the 20th century (231㎜) and the former indicated higher variability than the latter. Major wet/dry periodicities in May-June precipitation series reconstructed were 3 years in short term and 60∼80 years in long term. The present reconstructed data agreed to the ancient rain gauge 'Chukwooki' data (1777∼1907) of Seoul (central-west Korea) in low frequency variations except early 1800s.

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Effect of Several Herbicides in the Polyethylene - film Mulched Young Mulberry Field (P.E. 필름피복(被覆) 밀식(密植) 뽕밭에서의 수종(數種) 제초제(除草劑) 처리효과(處理效果))

  • Kim, Ho-Rak;Kwon, Yong-Woong;Cho, Yong-Woo
    • Korean Journal of Weed Science
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    • v.5 no.2
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    • pp.202-210
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    • 1985
  • Requirements in weed control in a mulberry field are much similar to those in orchards, but also feature a longer period of weed control of various kinds of persistent weeds, i.e., spring, summer, and winter annuals as well as perennials. In addition the mulberry tree is relatively more sensitive to herbicide injury. Hence, very few herbicides have been used in mulberry field. The present study was conducted to evaluate the usefulness of oxyfluorfen in comparison with alachlor and simazine, which are registered for ordinary mulberry field in Korea, for weed control efficacy in the new, rapidly increasing practice of transparent polyethylene-film mulched and densely planted younger mulberry culture. Dominant spring weeds were Galium spp., Erigeron spp., Polygonum senticosum, and Chenopodium spp. in the non-mulched interbed area in contrast to the Digitaria spp. and Potulaca spp, under mulch. Dominant summer weeds were Digitaria spp., Portulaca spp., Erigeron spp., Artemisia spp. and Calystegia japonica in the non-mulched interbed area while weeds did not occur significantly during summer under mulch which were shaded by vigorously growing mulberry trees. The weeds occurred under mulch in spring reduced shoot growth of young mulberry tree resulting in the reduced yield of mulberry leaves for silkworms. The weeds occurred in the interbed area did not affect until May, but interfered later summer- and fall-growth of mulberry tree. Early single spring application of alachlor(EC), simazine(WP) or oxyfluorfen(EC) at a rate of 650 g, 750 g or 350 g ai per ha, respectively, controlled most annuals satisfactorily to fall in the mulched bed area. In the nonmulched interbed area, however, thrice does of alchlor or simazine was necessary for satisfactory control of spring weeds, followed by summer application of alachlor or simazine at twice dose level as tank mixture with paraquat at 490 g ai per ha for satisfactory control of summer to fall weeds. Single spring application of oxyfluorfen at a rate of 1400 g ai per ha was persistently effective to control satisfactorily even summer and fall weeds. However, heavy rainfall splashed soil borne oxyfluorfen to the lower branch leaves causing some leaf burns. Spring application of oxyfluorfen at a rate of 350 g ai per ha followed by summer application of oxyfluorfen and paraquat tank mixture (350 g ai + 490 g ai) was the best choice for the non-mulched interbed area weed control among the treatments.

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Study on Sedimentation in Reservoir (저수지의 퇴사에 관한 연구)

  • 류희정;김치원
    • Water for future
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    • v.9 no.2
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    • pp.67-75
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    • 1976
  • With 9 existng reservoirs selected in the Sab-Gyo River Basin, the sedimentation of the reservoirs has been calculated by comparing the present capacity with the original value, which revealed its reduced reservoirs capacity. The reservoirs has a total drainage area of 6,792 ha, with a total capacity of 1,204.09 ha-m, and are short of water supply due to reduction of reservoirs capacity. Annual sedimention in the reservcire is relation to the drainage area, the mean of annual rain fall, and the slop of drainage area. The results of obtained from the investigation are summarized as follow; (1) A sediment deposition rate is very high, being about $9.19{m}^3/ha$ of drainage area, and resulting in the average decrease of reservoir capacity by 19.1%. This high rate of deposition could be mainly attributed to the serve denvdation of forests due to disor derly cuttings of tree. (2) An average unit storage of 415.8mm as the time of initial construation is decreesed to 315.59mm at present, as resultting, we could'nt supply water at 566.24ha. (3) A sediment deposition rate as a relation to the capacity of unit drainage area is as follow; $Qs=1.43 (c/a)^{0.531}$ (4) A sediment deposition rate as a relation to the mean of annval rainfall is as follow; $Qs=672.61 p^{0.024}$ (5) A sediment deposition rate as a relation to the mean slop of drainage area is follow; $Qs=267.21 S^{0.597}$

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A Fault Diagnosis and Reasoning Method based on Fault Tree (오류트리를 이용한 오류 진단 및 추론 기법)

  • Ko, Jae-Heon;Kim, Yeong-Duck;Min, Dong-Wook;Rhee, Hyun-Sook;Kim, Hoon-Ki;Jung, Suk-Yong;Park, Jeong-Min
    • Proceedings of the KAIS Fall Conference
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    • 2009.12a
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    • pp.441-444
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    • 2009
  • 자가 치유 시스템은 자율 컴퓨팅의 개념 중 하나로 사람의 개입 없이 시스템의 이상상태를 인식하고 정상상태로 복귀 가능한 시스템을 의미한다. 발생한 오류는 또 다른 오류를 유발할 수 있고, 하나 이상의 원인이 되는 오류나 사건이 있을 수 있다. 따라서 오류의 원인에 따른 치유전략을 필요로 하며 발생한 오류에서부터 전이될 수 있는 오류에 대한 추론을 요구하게 된다. 따라서 본 논문에서는 오류의 인과관계에 따른 진단 및 추론 기법을 제안하고자 한다. 제안사항을 통해 오류트리를 기반으로 하여 발생한 오류의 원인이 되는 오류를 파악할 수 있으며, 오류의 원인에 따른 치유 전략을 계획 가능하고, 발생 가능한 오류의 추론이 가능하다.

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Goal Tree based Testing Method for Self-healing System (자가 치유 시스템을 위한 목표 트리 기반 평가 기법)

  • Min, Dong-Wook;Kim, Yeong-Duck;Ko, Jae-Heon;Rhee, Hyun-Sook;Kim, Hoon-Ki;Jung, Suk-Yong;Park, Jeong-Min
    • Proceedings of the KAIS Fall Conference
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    • 2009.12a
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    • pp.436-440
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    • 2009
  • 자가 치유란 시스템에서 발생될 수 있는 에러나 오류를 미리 예상하거나 감지하고 시스템 스스로 치유함으로써 시스템의 오동작을 최소화하는 것을 의미한다. 자가 치유 시스템의 신뢰성을 높이기 위해서는 정확한 테스트 기법이 필요하다. 하지만 기존의 테스트 기법은 성공 또는 실패만으로 나타내기때문에 정량적인 평가가 불가능하다. 따라서 본 논문에서는 자가 치유 시스템이 달성해야 할 목표를 추출하고 관계에 따라 트리로 작성하여 이를 기반으로 시스템의 자가 치유 기법의 성공률을 정량적 측정하는 기법을 제안한다. 본 기법을 통해 자가 치유 시스템의 치유 결과를 정량적으로 평가 가능하고, 평가결과를 기반으로 치유 전략에 대한 문제점이 분석 가능하므로 자가 치유 시스템의 신뢰성 향상이 가능하다.

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HAN(Home Area Network) in Zigbee Safety Authentication Mechanism for Zigbee Device (홈 네트워크 디바이스에서 ZigBee기반의 안전한 인증 메커니즘)

  • Choi, Ji-Hoon;Kim, Jung-Jae;Jun, Moon-Seog
    • Proceedings of the KAIS Fall Conference
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    • 2010.11a
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    • pp.267-271
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    • 2010
  • Zigbee는 단말에 대한 경제성이 뛰어나고 저 전력통신을 이용하기 때문에 수명이 길다. Mesh, Tree, Star 등 다양한 방식의 토플리지 구조를 지원 하며 확장성이 뛰어나 군사적인 용도, 환경 모니터링 시스템 등 많은 분야에 사용되고 있다. 최근 스마트그리드환경을 구축함에 있어 Zigbee는 HAN(Home Area Network)에 표준으로 사용될 예정이며 현재는 Zigbee를 이용한 AMR(Automatic Meter Reading)을 시범 중에 있다. 일반적으로 ZIgbee Network은 ZC(Zigbee Coordinator), ZCH(Zigbee Cluster Head), ZE(Zigbee End Device) 3가지로 구성되며, Zigbee Network에서 발생할 수 있는 취약점은 허가되지 않은 디바이스의 접근, 라우터의 흐름을 조작하는 방법, ZC(Zigbee Coordinator)와 ZE(Zigbee End Device)사이의 키 전송 시 안전하지 않은 채널을 이용하여 전송되는 문제가 발생된다. 본 논문에서는, TCP(Third Party Center)를 이용함으로써, ZE와 ZC간의 키 생성 시 발생하는 취약점을 보완하였다. 또한 인증절차를 강화함으로써 ZE(Zigbee End Device)에서 발생 할 수 있는 취약점을 보완하고자 하였으며 RS(Register Server)를 이용하여 HAN에 존재하는 디바이스에 대하여 실시간 모니터링이 가능하게 하였다.

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Application of Deep Learning: A Review for Firefighting

  • Shaikh, Muhammad Khalid
    • International Journal of Computer Science & Network Security
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    • v.22 no.5
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    • pp.73-78
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    • 2022
  • The aim of this paper is to investigate the prevalence of Deep Learning in the literature on Fire & Rescue Service. It is found that deep learning techniques are only beginning to benefit the firefighters. The popular areas where deep learning techniques are making an impact are situational awareness, decision making, mental stress, injuries, well-being of the firefighter such as his sudden fall, inability to move and breathlessness, path planning by the firefighters while getting to an fire scene, wayfinding, tracking firefighters, firefighter physical fitness, employment, prediction of firefighter intervention, firefighter operations such as object recognition in smoky areas, firefighter efficacy, smart firefighting using edge computing, firefighting in teams, and firefighter clothing and safety. The techniques that were found applied in firefighting were Deep learning, Traditional K-Means clustering with engineered time and frequency domain features, Convolutional autoencoders, Long Short-Term Memory (LSTM), Deep Neural Networks, Simulation, VR, ANN, Deep Q Learning, Deep learning based on conditional generative adversarial networks, Decision Trees, Kalman Filters, Computational models, Partial Least Squares, Logistic Regression, Random Forest, Edge computing, C5 Decision Tree, Restricted Boltzmann Machine, Reinforcement Learning, and Recurrent LSTM. The literature review is centered on Firefighters/firemen not involved in wildland fires. The focus was also not on the fire itself. It must also be noted that several deep learning techniques such as CNN were mostly used in fire behavior, fire imaging and identification as well. Those papers that deal with fire behavior were also not part of this literature review.

A Study on Correlation Between the Growth of Korean Red Pine and Location Environment in Temple Forests in Jeollanam-do, Korea (전남 사찰림에서의 소나무 생육과 입지환경간의 상관관계 연구)

  • Park, Seok-Gon;Hong, Suk-Hwan;Oh, Chan-Jin
    • Korean Journal of Environment and Ecology
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    • v.31 no.4
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    • pp.409-419
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    • 2017
  • Although Korean red pine (Pinus densiflora) forests near temples are valuable as forests of the cultural landscape, they are likely to be deteriorated because of vegetation succession and climate changes. The purpose of this study is to investigate the vegetation structure, the pine vitality, and the site environmental characteristics of the pine forests near temples to identify the correlation between pine tree growth and location environment. We selected Chuneunsa, Wonhyosa, Jeungsimsa, and Taeansa Temples since these four areas still had the healthy pine forests. In all four studied area, the pine trees dominate the canopy layers while the deciduous broadleaf trees mostly inhabited appeared in the lower layers. The growth of pine trees in Jeungsimsa and Wonhyosa areas was not as good as Chuneunsa area where the pine trees tended to be older. We found higher total nitrogen content in soil in Jeungsimsa area than other areas, maybe because of increase in total nitrogen caused by the development of low vegetation in the area. This peculiarity may have led to the pine trees in the area to fall behind the deciduous broadleaf trees in competition for nitrogen nutrient and thus to show deteriorated growth. The altitude and the twig length showed a negative correlation as did the degree of slope and the mean importance percentage of the pine tree. In other words, the growth environment such as soil became poorer when the altitude and the degree of slope increased, and thus the growth amount and dominance of the pine trees were lower. The degree of slope showed a positive correlation with the twig length of the pine tree. Within boundaries of location environment where the pine tree forests were dominant, it seemed that growth of the pine trees was more favorable as the slope was steeper because the trees could avoid competition with deciduous broadleaf trees. On the other hand, the growth of pine trees deteriorated as the electrical conductivity of soil increased; increase in soil nutrients might have accelerated vegetation development of deciduous broadleaf trees and thus aggravated the growth environment of pine trees to negatively affect maintaining the health of the pine tree forests.