• 한국전산유체공학회:학술대회논문집
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• 2008.03b
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• pp.80-83
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• 2008

The characteristics of the spread of a forest fire are generally related to the attributes of combustibles, geographical features, and meteorological conditions, such as wind conditions. The most common methodology used to create a prediction model for the spread of forest fires, based on the numerical analysis of the development stages of a forest fire, is an analysis of heat energy transmission by the stage of heat transmission. When a forest fire breaks out, the analysis of the transmission velocity of heat energy is quantifiable by the spread velocity of flame movement through a physical and chemical analysis at every stage of the fire development from flame production and heat transmission to its termination. In this study, the formula used for the 1-dimensional surface forest fire behavior prediction model, derived from a numerical analysis of the surface flame spread rate of solid combustibles, is introduced. The formula for the 1-dimensional surface forest fire behavior prediction model is the estimated equation of the flame spread velocity, depending on the condition of wind velocity on the ground. Experimental and theoretical equations on flame duration, flame height, flame temperature, ignition temperature of surface fuels, etc., has been applied to the device of this formula. As a result of a comparison between the ROS(rate of spread) from this formula and ROSs from various equations of other models or experimental values, a trend suggesting an increasing curved line of the exponent function under 3m/s or less wind velocity condition was identified. As a result of a comparison between experimental values and numerically analyzed values for fallen pine tree leaves, the flame spread velocity reveals has a error of less than 20%.

• Journal of Korean Society of Forest Science
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• v.60 no.1
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• pp.1-9
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• 1983

The leaves and young shoots of several broad leaf trees infected with powdery mildew fungi were collected and observed for the purpose of seeking for the host plants and identifying its pathogenic fungi in the arboretum of Forest Research Institute, Seoul from October to November 1982. Of these, Prunus serrulata var. spontanea, Prunus padus, Celastrus flagellaris, and Fraxinus ${\times}$ chiisanensis were found out to be new host plants of powdery mildew fungi in korea. Morphological characteristics of imperfect state and perfect state of powdery mildew fungi on 4 new host plants were examined. These pathogenic fungi were identified as Podosphaera tridactyla, Uncinula sengokui, and Uncinula fraxini.

• Journal of Biosystems Engineering
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• v.41 no.3
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• pp.255-262
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• 2016

Purpose: Fuji apples are one of the top selling exports for South Korea bringing in over $233.4 million in 2013. However, during the last few decades, about half of the Fuji apple orchards have been infected by Apple Marssonina Blotch disease (AMB), a fungal disease caused by Diplocarpon mali., which takes about 40 days to exhibit obvious visible symptoms. Infected leaves turn yellow and begin growing brown lesions. AMB promotes early defoliation and reduces the quality and quantity of apples an infected tree can produce. Currently, there is no prediction model for AMB on the market. Methods: The Precision Agriculture Laboratory (PAL) at the University of Florida (UF) has been working with the National Academy of Agricultural Science, Rural Development Administration, South Korea to investigate the use of hyperspectral data in creating an early detection method for AMB. The RDA has been researching hyperspectral techniques for disease detection at their Apple Research Station in Gunwi since 2012 and disseminates its findings to the local farmers. These farmers were surveyed to assess the state of knowledge of AMB in the area. Out of a population of about 750 growers, 111 surveys were completed (confidence interval of +/- 8.59%, confidence level of 95%, p-value of 0.05). Results: The survey revealed 32% of the farmers did not know what AMB was, but 45% of farmers have had their orchards infected by AMB. Twenty-five percent could not distinguish AMB from other symptoms. Overwhelmingly, 80% of farmers strongly believed an early detection method for AMB was necessary. Conclusions: The results of the survey will help to evaluate the outreach programs of the RDA so they can more effectively educate farmers on the identifying, treating, and mediating AMB.

• Korean Journal of Organic Agriculture
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• v.18 no.4
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• pp.541-548
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• 2010

This study was established on which the selenium (Se), known as one of the functional elements in the human body, treatment was the most effective for the Se uptake in the soil and tree. Se treatments included foliar application, soil fertigation, and trunk injection. Se fertigation and control had similar soil $P_2O_5$, K, and Mg concentrations, and calcium and Se concentrations in the soil were greater on the control and Se fertigation, respectively. Leaf characteristics were not different among the treated trees. No differences were observed for the leaf K and Ca concentrations among the treated trees, and foliar Mg was greater on the Se treated trees than the control. Se foliar application and trunk injection had greater Se concentrations in the leaves and fruits than the Se fertigation and control.

• Journal of Life Science
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• v.18 no.6
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• pp.759-763
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• 2008

Halophila ovalis (R. Br.) Hook. fil. was first collected from the Ando, Yeosu, Korea in 2007. H. ovalis is Widely distributed from sub-tropical to even tropical areas and produces the seeds using bisexual reproduction. Its leaf shape was oblong to ovate. Its leaf blades were rigid in texture, with a strong support to the leaf. Erect shoots arose at irregular intervals along the rhizome. The distance between the intramarginal vein and leaves margin was small. Nucleotides in ITS 1 and ITS 2 regions between the Korean and Japanese H. ovalis were found to be 100% similar, whereas Korean H. ovalis was found to have four nucleotides in the positions of 202 bp to 206 bp for 5.8S. In the analysis of the phylogenetic relationship using NJ method, Korean H. ovalis had a monophyletic genetic tree with Japanese H. ovalis, but no phylogenetic relationship with types from the Philippines, Australia, Malaysia, and Vietnam. The first occurrence of H. ovalisin Korea was associated with a strong migration of gene flow from Japan and high water temperature caused by the variations in climate.

• Applied Chemistry for Engineering
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• v.21 no.5
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• pp.575-580
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• 2010

Forest fires in Korea, having forest coverage of 70%, have kept increasing in number and scale since the middle of 1990's. Although deposited fallen leaves in forests such as herbaceous plants, conifers, and broadleaf trees are used as a medium for forest fires, the pyrolysis and combustion characteristics of the various species of trees are hardly studied. Oriental oak is the representative broadleaf tree in domestic forests, and pyrolysis and combustion of oriental oak leaf were carried out by thermogravimetic analysis (TGA). The leaf of oriental oak was ignited at $239^{\circ}C$ whereas pyrolysis started at $250^{\circ}C$. The corresponding kinetic parameters including activation energy and pre-exponential factor were determined by differential method over the degree of conversions. The values of activation energies for pyrolysis were increased as the conversion increases from 10% to 80%, whereas those of values were decreased during combustion.

• Korean Journal of Agricultural and Forest Meteorology
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• v.3 no.2
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• pp.81-87
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• 2001

Populus euramericana and Betula platyphylla var. japonica have been identified as possible species for use for phytoremediation of landfills. To identify the capacity of waste leachate absorption in Populus euramericana and Betula platyphylla var, japonica, four different treatments were applied to these seedlings: leachate solution (100% leachate), 50% dilution (50% leachate: 50% water, v/v) and 25% dilution (25% leachate: 75% water, v/v) were applied to these two species. After the experiment, concentrations of heavy metals in tree biomass were analyzed by Inductively Coupled Plasma emission spectrometer (ICP). These two species can take up the hazardous parts of the leachate such as heavy metals. Especially, these species showed good absorption capacity of Al, Cr, and Fe elements. The result of this study suggested that these two species can take up the toxic materials through their roots and transport them to stems or leaves.

• Journal of the Korean Institute of Landscape Architecture
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• v.37 no.5
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• pp.90-97
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• 2009

Sedum takesimenses among the Korean Native Genus Sedum was selected as evergreen ground covers during winter in the central districts of Korea. In order to obtain basic information for production as a pot flower with good quality, the effects of pinching frequencies on growth and flowering of S. takesimense were investigated. S. takesimense plant height became much shorter and numbers of lateral shoots were increased with increased pinching. Shoots of S. takesimense treated with 30% pinching during 2004 and 2005 showed greater length and less number of lateral shoots than those with 60% pinching. Leaves of S. takesimense treated with 70% shading showed a dark green color and had a longer shoot length and a lower number of shoots than cultivation under full sunlight. Therefore, Korean native S. takesimense will be utilized as ground cover treated with 70% shading or under a tree. Therefore, S. takesimense will be promising as ground cover materials in the central districts of Korea.

• Mycobiology
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• v.30 no.1
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• pp.22-26
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• 2002

This study was carried out to investigate the possibility for seeds germination of Gastrodia elata using symbiotic fungi. Since seeds of G. elata are very small and lack an endosperm and other nutrients, their germination is difficult without requirement for external nutrients. Out of twenty six isolates collected from protocorms of G. elata and roots of native orchids inhabited in wild, two strains(H-2 and H-21) were observed to stimulate the seed germination of G. elata. The seed germination of G. elates was excellent on oak tree leaves medium. The optimal conditions for mycelial growth of symbiotic fungi were $25^{\circ}C$ and pH 6.0, respectively. The mycelial growth of H-2 strain was excellent on YMA medium, while H-21 was poor on PDA medium. In case of carbon sources, the mycelial growth of H-2 and H-21 was good on media supplemented with glucose and dextrin, respectively. Calcium nitrate was good for mycelial growth of H-2 strain as a nitrogen sources, whereas urea was effective to H-21 strain.

• Asian Journal of Atmospheric Environment
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• v.7 no.1
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• pp.17-24
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• 2013

Fog deposition onto the cool-temperate deciduous forest around Lake Mashu in northern Japan was estimated by the inferential method using the parameterizations of deposition velocity and liquid water content of fog (LWC). Two parameterizations of fog deposition velocity derived from field experiments in Europe and numerical simulations using a detailed multi-layer atmosphere-vegetation-soil model were tested. The empirical function between horizontal visibility (VIS) and LWC was applied to produce hourly LWC as an input data for the inferential method. Weekly mean LWC computed from VIS had a good correlation with LWC sampled by an active string-fog collector. By considering the enhancement of fog deposition due to the edge effect, fog deposition calculated by the inferential method using two parameterizations of deposition velocity agreed with that computed from throughfall data. The results indicated that the inferential method using the current parameterizations of deposition velocity and LWC can provide a rough estimation of water input due to fog deposition onto cool-temperature deciduous forests. Limitations of current parameterizations of deposition velocity related to wind speed, evaporation loss of rain and fog droplets intercepted by tree canopies, and leaf area index were discussed.