• 제목/요약/키워드: forest gap

검색결과 146건 처리시간 0.022초

A Comparison of Litterfall Dynamics in Three Coniferous Plantations of Identical Age under Similar Site Conditions

  • Jeong, Jae-Yeob;Kim, Choon-Sig;An, Hyun-Chul;Cho, Hyun-Seo;Choo, Gap-Chul
    • Journal of Ecology and Environment
    • /
    • 제32권2호
    • /
    • pp.97-102
    • /
    • 2009
  • This study was carried out to evaluate litterfall dynamics in three adjacent coniferous tree plantations (larch: Larix leptolepis; red pine: Pinus densiflora; rigitaeda pine: P. rigitaeda) planted in the same year (1963), and growing under similar environmental conditions in the Sambong Exhibition Forests, Hamyang-gun, Gyeongsangnam-do. Litter was collected monthly between July 2006 and June 2008. Needle, broad leaf and total litter inputs followed a similar monthly pattern in the three coniferous plantations. The amounts of needles, flowers, and miscellaneous litter were significantly lower in the larch than in the two pine plantations, while branch litter was significantly higher in the larch than in the two pine plantations. Average total litterfall for two years was significantly higher for the pine (5,475 kg $ha^{-1}\;yr^{-1}$ for red pine and 5,290 kg $ha^{-1}\;yr^{-1}$ for rigitaeda pine) plantations than for the larch (3,953 kg $ha^{-1}\;yr^{-1}$ plantation. Needle litter comprised about 73.1% of total litterfall for the rigitaeda pine, 70.8% for the red pine and 62.9% for the larch plantations. Our results demonstrate that litterfall inputs can be affected by tree species.

A Study on Diabetes Management System Based on Logistic Regression and Random Forest

  • ByungJoo Kim
    • International journal of advanced smart convergence
    • /
    • 제13권2호
    • /
    • pp.61-68
    • /
    • 2024
  • In the quest for advancing diabetes diagnosis, this study introduces a novel two-step machine learning approach that synergizes the probabilistic predictions of Logistic Regression with the classification prowess of Random Forest. Diabetes, a pervasive chronic disease impacting millions globally, necessitates precise and early detection to mitigate long-term complications. Traditional diagnostic methods, while effective, often entail invasive testing and may not fully leverage the patterns hidden in patient data. Addressing this gap, our research harnesses the predictive capability of Logistic Regression to estimate the likelihood of diabetes presence, followed by employing Random Forest to classify individuals into diabetic, pre-diabetic or nondiabetic categories based on the computed probabilities. This methodology not only capitalizes on the strengths of both algorithms-Logistic Regression's proficiency in estimating nuanced probabilities and Random Forest's robustness in classification-but also introduces a refined mechanism to enhance diagnostic accuracy. Through the application of this model to a comprehensive diabetes dataset, we demonstrate a marked improvement in diagnostic precision, as evidenced by superior performance metrics when compared to other machine learning approaches. Our findings underscore the potential of integrating diverse machine learning models to improve clinical decision-making processes, offering a promising avenue for the early and accurate diagnosis of diabetes and potentially other complex diseases.

한국임산물무역(韓國林産物貿易)의 동태(動態)와 전망(展望) (A Study on Trends and Prospects of Forest Products Trade in Korea)

  • 최민휴
    • Journal of the Korean Wood Science and Technology
    • /
    • 제14권2호
    • /
    • pp.43-49
    • /
    • 1986
  • 국내(國內) 산림자원(山林資源)이 부족(不足)한 한국(韓國)의 입장(立場)에서 볼 때 목재(木材)의 수급균형(需給均衡)을 위(爲)하여 외재(外材)에 크게 의존(依存)해야함은 어찌할 수 없다 하겠으나, 다른 한편 이에 상응(相應)하는 각종(各種) 임산물(林産物)의 수출(輸出)을 통(通)하여 어떻게 임산물(林産物)의 무역수지(貿易收支)의 균형(均衛)에 유의(留意)하여 왔는가를 지난 약(約) 20 여년간(餘年間)의 시계별(時系別) 자료(資料)를 통(通)하여 살펴보았다. 1960년대(年代)부터 1970년대말(年代末)까지는 이러한 균형유지(均衝維持)가 지속(持續)되었으나, 1979년(年) 제(第)2차(次) 유류파동(油類波動) 이후(以後)로는 점차(漸次) 불균형(不均衡)이 노정(露呈)된체 오늘에 이르고 있다. 그러나 세계경제(世界經濟)의 무역의존도(貿易依存度)는 날로 증대(增大)되어가는 추세(趨勢)에 있고, 한국경제(韓國經濟)가 처(處)한 제반여건(諸盤與件)이 대외지향정책(對外指向政策)을 채택(採擇)하지 않을 수 없는 실정(實情)에 놓여 있는 한(限), 국민경제(國民經濟)의 일익(一翼)을 담당(擔當)하고 있는 임업부문(林業部門)에 있어서도 임산물(林産物) 무역(貿易)의 확대(擴大)를 통(通)하여 그 수지균형(收支均衡)을 회복(回復)하는 데 최선(最善)의 노력(努力)을 기우릴 필요(必要)가 있다. 한편 목재수입정책(木材輸入政策)은, 외재의존도(外材依存度)가 85%임에 비추어 목재수급(木材需給)과 물가안정(物價安定)에 외재(外材)의 비중(比重)이 매우 클 뿐아니라, 그 가격기능(價格械能)을 통(通)하여 국내(國內) 목재가격조성(木材價格造成)을 위(爲한) 투자환경조성(投資環境造成)에도 큰 영향을 미치고 있으므로, 신중(愼重)을 기(期)할 필요(必要)가 있으며, 이러한 관점(觀點)에서 현행(現行) 목재수입(木材輪入) 자유화제도(自由化制度)는 마땅히 재검토(再檢討)되어야 한다.

  • PDF

Mining Information in Automated Relational Databases for Improving Reliability in Forest Products Manufacturing

  • Young, Timothy M.;Guess, Frank M.
    • International Journal of Reliability and Applications
    • /
    • 제3권4호
    • /
    • pp.155-164
    • /
    • 2002
  • This paper focuses on how modem data mining can be integrated with real-time relational databases and commercial data warehouses to improve reliability in real-time. An important Issue for many manufacturers is the development of relational databases that link key product attributes with real-time process parameters. Helpful data for key product attributes in manufacturing may be derived from destructive reliability testing. Destructive samples are taken at periodic time intervals during manufacturing, which might create a long time-gap between key product attributes and real-time process data. A case study is briefly summarized for the medium density fiberboard (MDF) industry. MDF is a wood composite that is used extensively by the home building and furniture manufacturing industries around the world. The cost of unacceptable MDF was as large as 5% to 10% of total manufacturing costs. Prevention can result In millions of US dollars saved by using better Information systems.

  • PDF

광조건에 따른 식물의 엽온 특성 (Leaf Temperature Characteristics being Affected by Light Regimes)

  • 박용목
    • 한국환경과학회지
    • /
    • 제20권12호
    • /
    • pp.1599-1605
    • /
    • 2011
  • To evaluate heat environment surrounding plants diurnal change of leaf temperature in the broad-leaved deciduous and evergreen trees was measured with microclimatic environmental factors including global solar radiation, and upward and downward long wave radiation. Maximum daily solar radiation was 961.2 and 976.3 w/$m^2$ in August 9 and 23, respectively. Upward long wave radiation was slightly higher than downward long wave radiation, showing 404.2 w/$m^2$ in August 9 and 394.5 w/$m^2$ in August 23. In addition, daily maximum vapor pressure deficit was 5.42 and 6.84 kPa in August 9 and 23, respectively, indicating high evaporative demand. Quercus glauca and Acer mono was differently responded to changing light regimes. On August 9, leaf temperature at the top-positioned leaves of Acer plants was higher than air temperature as well as those of Quercus plants in the morning. This indicates that stomata in Acer plants were closed by heat stress or water stress in the morning, while Quercus plant maintained active transpiration by opening stomata. These results indicated that improved light regimes such as gap opening in the closed forest may not always affect positively in the physiology of understory plants.

Households' Characteristics, Forest Resources Dependency and Forest Availability in Central Terai of Nepal

  • Panta, Menaka;Kim, Kyehyun;Lee, Cholyoung
    • 한국산림과학회지
    • /
    • 제98권5호
    • /
    • pp.548-557
    • /
    • 2009
  • For centuries, forests have been a key component of rural livelihood. They are important both socially and economically in Nepal. Firewood and fodder are the basic forest products that are extracted daily or weekly basis in most of the rural areas in Nepal. In this study, a field survey of 100 households was conducted to examine the degree of forest dependency and forest resource availability, households' livelihood strategy and their relationship with forest dependency in Chitwan, Nepal. A household' response indexes were constructed, Gini coefficient, Head Count Poverty Index (HCI) and Poverty Gap Index (PGI) were calculated and one way ANOVA test was also performed for data analysis. Data revealed that 82/81% of all households were constantly used forest for firewood and fodder collection respectively while 42% of households were used forest or forest fringe for grazing. The Forest Product Availability Indexes (FPAI) showed a sharp decline of forest resources from 0.781 to 0.308 for a 20-yr time horizon while timber wood was noticeably lowered than the other products. Yet, about 33% of households were below the poverty threshold line with 0.0945 PGI. Income distribution among the household showed a lower Gini coefficient 0.25 than 0.37 of landholdings size. However, mean income was significantly varies with F-statistics=246.348 at P=0.05 between income groups (rich, medium and poor). The extraction of firewood, fodder and other forest products were significantly different between the income group with F-statistics=16.480, 19.930, 29.956 at P=0.05 respectively. Similarly, landholdings size and education were also significantly different between the income groups with F-statistics=4.333, 5.981 at P=0.05 respectively. These findings suggested that income status of households was the major indicator of forest dependency while poor and medium groups were highly dependent on the forests for firewood, fodder and other products. Forest dependency still remains high and the availability of forest products that can be extracted from the remaining forestlands is decreasing. The high dependency of households on forest coupled with other socioeconomic attributes like education, poverty, small landholders and so on were possibly caused the forest degradation in Chitwan.Therefore, policy must be directed towards the poor livelihood supporting agenda that may enhance the financial conditions of rural households while it could reduce the degree of forest dependency inspired with other income generating activities in due course.

농촌 소나무림에서 산불에 의한 식생변화와 유용미생물의 적용 (Vegetation Change after A Forest Fire in a Rural Japanese Red Pine Forest and Applications of Effective Microorganism)

  • 여지선;김기대
    • 한국환경복원기술학회지
    • /
    • 제11권4호
    • /
    • pp.46-56
    • /
    • 2008
  • This study examined the natural restoration of vegetation through monitoring of the development of a vegetation community from 2006 through 2007 after a forest fire. Approximately 5,000 $m^2$ in a forest near Topyeon-ri, Kangnae-myeon, Chungcheongbuk-do with Japanese red pine (Pinus densiflora) forest and its floor vegetation had been completely burned by a fire in April 2005. This area and another nearby Japanese red pine forest were selected as the experiment site and the control site, respectively. Vegetation survey was conducted at the experiment site and the control site. A seed bank experiment was carried out in the greenhouse to examine underground vegetation. Effective microorganism(EM) was applied to the seed bank experiment to estimate its effects on the direction of ecological succession. According to the results, a total of 36 plant species including shrub and herbaceous species were discovered in the experiment site. Quercus serrata, Lespedeza cyrtobotrya, and Castanea crenata, Rubus crataegifolius, Oplismenus undulatifolius, and Carex lanceolata were among the most abundant species. Biomass in the experiment site reached 2.4 times biomass than those in the control site, indicating the productivities of shrub and herbaceous layers are better in the experiment site. According to the result of the soil seed bank experiment of the experiment site, a total of 182 plants of 14 species were recorded. In addition, a total of 13 plants of 2 species were found from soil seed bank of the experiment site applied by EM. If EM is applied to the burned site, it will control the budding of herbaceous plants, creating the gap between herbaceous plants. This loss of competition is expected to help the restoration of trees in the burned area.

목재수납장 구매자의 소비성향 및 사회·경제적 특성에 따른 산림인증 인식도 조사 (Recognition of Forest Certification by Consumption Propensity and Socio-Economic Characteristics of Wood Cabinet Consumers)

  • 신혜진;김의경;김동현;김현근
    • 농업생명과학연구
    • /
    • 제45권6호
    • /
    • pp.57-63
    • /
    • 2011
  • 이 연구는 목재수납장의 잠재적 구매자를 대상으로 소비성향 및 사회 경제적 특성에 따른 산림인증의 인식정도를 파악하기 위해 수행하였다. 총 90부의 설문지 중 유효부수 88부를 분석한 결과, SFM과 FSC에 대한 전체 응답자의 인식도는 평균 2.25와 2.20(5점 리커트 기준)으로 비교적 낮게 나타났다. 친환경 그룹과 비친환경 그룹의 응답자는 80.7%와 18.2%의 비중을 차지하였으며, 모든 설문항목에 대해 그룹간 유의한 차이를 나타냈다. 각 그룹 내에서 SFM과 FSC를 인식하고 있는 응답자는 친환경 그룹이 약 31%, 비친환경 그룹이 5.6%(SFM)와 2.8%(FSC)를 차지하였다. 소비자 유형별 응답자의 사회 경제적 특성은 친환경 그룹의 기혼율과 평균연령 및 월평균 가계소득이 비친환경 그룹에 비해 약 1.3배 이상 높은 것으로 나타났다.

Gap characteristics and natural regeneration in Mt. Makiling rainforest, the Philippines

  • Kim, Hyun-Ji;Kim, Tae-Geun;Kim, Eun-Hee;Castillo, Manuel L.;Cho, Do-Soon
    • Journal of Ecology and Environment
    • /
    • 제34권2호
    • /
    • pp.157-165
    • /
    • 2011
  • This study was conducted to determine the characteristics of gaps and natural regeneration of trees on Mt. Makiling, the Philippines. Canopy gaps in or around two 1-ha permanent plots and on 3-km line transects were investigated. Most of the gaps studied were formed or affected by Typhoon Milenyo, which hit the study site in September 2006. The most frequent mode of gap maker death was snap-off, whereas uprooting was relatively less important. The most frequent gap maker was balobo (Diplodiscus paniculatus) followed by magabuyo (Celtis luzonica) and katmon (Dillenia philippinensis). In contrast, the most frequent gap filler was magabuyo (C. luzonica). At the sapling layer, the most important species was magabuyo (C. luzonica), but there was a high proportion of lianas and palms. Most of the gaps had leaf area index (LAI) values between 3 and 5. A clear trend of a decrease in gap size and an increase in LAI was observed for 2 years from 2007 to 2009. New seedlings emerged very abundantly during the same time period. The rapid changes in the gaps were partially due to the excellent capability of tropical trees to resprout after the crown or stem was damaged by the typhoon. This study on gap dynamics may contribute to a better understanding of the natural regeneration process of trees in tropical rainforests.