• Journal of Korean Society of Forest Science
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• v.96 no.5
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• pp.602-608
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• 2007

Forest plantations become important strategy not merely for the financial aspect, but for carbon sequestration and ecosystem stability. Forest plantations increase the density of the forest biomass, which reduce the increase in atmospheric carbon dioxide. Biomass density is also a useful variable for comparing structural and functional attributes of forest ecosystems across a wide range of environmental conditions. In this study, carbon sequestration of teak (Tectona grandis Linn. f.) in the individual tree and plantation levels estimation was carried out Site-specific allometric equation for the estimation of teak tree biomass was developed based on the direct measurement of fifteen (15) harvested trees in the Oak-twin Township of the Bago Yoma Region, Myanmar. A regression equation of the diameter at breast height (DBH) and the aboveground biomass (carbon content) was constructed to estimate the carbon storage level of plantations, which averaged 79 ton/ha. The average carbon accumulation in the soil (up to 30 cm in depth) was estimated 38.89 ton/ha, The highest mean annual increment (MAI) of total carbon was found in the 6-yr-old teak plantation (12.10 ton/ha/yr) whereas the lowest MAI was in the 26-yr-old teak plantation (4.31 ton/ha/yr).

• The Korean Journal of Ecology
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• v.16 no.1
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• pp.75-91
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• 1993

Structure and dynamics of Abies koreana community in Mt. Gaya were studied to provide the basic data for conservation of Abies koreana community, an endemic species in Korea. A. koreana community of this study site was composed of tree layer (4~7m), subtree layer (2~4m), shrub layer (1~2m), and herb layer (below 1m). The heights of tree and subtree layers were low. Floristic composition showed that this study site was subalpine and dry site. In frequency distribution diagram of diameter classes of major species consisting of A. koreana community, those of both A. koreana and other species showed reverse J-shaped types. From these results, it was estimated that A. koreana community of this site might be maintained continuously as a stable climax state like present state. In the spatal distribution diagram of major species, saplings of A. koreana were established under the canopy of A. koreana and Pinus koraiensis and under the dead tree of A. koreana. From these results, it was known that A. koreana saplings were recruited before the community was disturbed and regeneration was accomplished by advance regeneration pattern, in which these saplings established before occurrence of disturbance fill with open site originated from death of mature tree. Growth of annual rings was variable among individuals, it was estimated that such variation was originated in that growth of each individual relates to microclimatic conditions rather than macroclimatic ones. Ecological longevity of A. koreana in this study site estimated by disturbance types and age of dead trees was about 120 years.

• Asian Journal of Atmospheric Environment
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• v.5 no.2
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• pp.105-112
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• 2011

In order to investigate the effects of local and synoptic meteorological conditions on urban scale particulate air pollutants observed over the Busan coastal area, power spectrum analysis was applied to observed particulate matter with an aerodynamic diameter $\leq10\;{\mu}m$ ($PM_{10}$) for the period from 1 October, 1993 to 31 December, 2004. Fast Fourier Transform (FFT) analysis was used to obtain the hourly mean observed $PM_{10}$ concentrations to identify different periodicity scales of $PM_{10}$ concentrations. The results showed that, aside from the typical and well-known periodicities such as diurnal and annual variations caused by anthropogenic influences, three other significant power spectral density peaks were identified: 7-day, 21-day and 2.25-year periodicities. Cospectrum analysis indicated that the seven-day variations were closely related to the synoptic meteorological conditions such as weak wind speed, which are relevant to the stagnant high pressure system slowly passing through the Korean Peninsula. The intra-seasonal 21-day variation was negatively correlated with wind speed but was consistently positively correlated with relative humidity, which is related to aerosol formation that can be achieved as a result of the hygroscopic characteristics of aerosols. However, the quasibiennial 2.25-year variation was correlated with the frequency of Asian dust occurrence, the periodicities of which have been recorded inter-annually over the Korean Peninsula.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.23 no.6
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• pp.392-399
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• 2011

Ground-coupled heat pump(GCHP) systems have been shown to be an environmentally-friendly, efficient alternative to traditional cooling and heating systems in both residential and commercial applications. Although some work related to performance evaluation of GCHP systems for commercial buildings has been done, relatively little has been reported on the residential applications. The aim of this study is to evaluate the cooling and heating performances of a vertical GCHP system applied to an artificial detached house($117\;m^2$) in Seoul. For this purpose, a typical design procedure was involved with a combination of design parameters such as building loads, heat pump capacity, borehole diameter, and ground thermal properties, etc. The cooling and heating performance simulation of the system was conducted with different prediction times of 8760 hours and 240 months. The performance characteristics including seasonal system COP, average annual power consumption, and temperature variations related to ground heat exchanger were calculated and compared.

• KSBB Journal
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• v.18 no.2
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• pp.140-144
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• 2003

The artificial sewage was treated using a vertical flow zeolite-filled reed bed. The artificial sewage was fec into the reed bed for 10 minutes every 6 hours at the hydraulic load 314 L/$m^2$ \ulcorner day. The filtering height of the reed bed was 100 cm and the zeolite mixture was filled in the reed bed. The mixture consisted of the same volume of two types of zeolites ; 0.5~1 mm and 1~3 mm in diameter. Annual average removal efficiency was CO$D_{Cr}$ 95.1%, T-N 49.5%, $NH{_4^+}$-N 99.4% and T-9 56.4%. T-N removal efficiency decreaced remarkably from 73 to 27% with the operating time. Most of T-P was adsorbed in the uper area of the reed bed. The major portion of adsorbed phosphorus was composed of Fe-, Ca- and reductant selubele Fe-P.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.39 no.6
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• pp.472-479
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• 2006

The sexual maturity and reproductive cycle of the common squid, Todarodes pacificus captured from the East Sea, Korea, between January 2004 and January 2006, were investigated by documenting changes in the gonadosomatic index (GSI), gonad development, and oocyte size frequency distribution. The GSI of females began to increase in July, reached a maximum in August, and then gradually decreased. The GSI of males increased from July to March. Using gonad histological observations, we identified four oocyte developmental stages. The changes in GSI and gonad tissue resulted in the classification of the annual reproductive cycle into the following four successive stages: immature (April to June), growing (June to July), mature (July to August), and ripe and spawning (August to March). According to the oocyte diameter size frequency distribution in the ovary, this species appeared to have asynchronous oocyte development and one spawning time.

• Journal of Ginseng Research
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• v.5 no.2
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• pp.92-98
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• 1981

This experiment was carried out to inverstigate the characteristics of growth of ginseng Plant on field conditions as affected by seedling weight. Weight of seedling ranged from 0.4 to 1.8g were divided into seven classes at interval of 0.2g. The heavy seedlings showed superiority in stem length, stem diameter, leaf area, number of palmate leaf and leaflets and root weight in 2-,3-, and 4-age as compared to light ones. The heavy seedlings also showed superiority in the ratio of inflorescence appearance in 2-age and seed product in 4-age as compared to light ones, but there were no significant difference in the ratio of missing-plant and the cracking. of root. The differences of growth in field condition as affected by seedling weight were diminished as the age progressed, and the annual growth rates of root of light seedling were high in older plant.

• Journal of Plant Biology
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• v.34 no.1
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• pp.9-18
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• 1991

This study deals with the effect of dwarf growth on xylem structure, especially on the dimension of xylem elements described for 12 species of naturally occuring dwarf trees. The length and tangential diameter of tracheary elements and fibers in dwarf trees appear to be shorter and narrower than those in normal trees. Radial width and cell number of the same annual rings are narrower and smaller in dwarf trees than those in normal trees. Height of rays in dwarf trees is lower than that in normal trees. Dwarf conifers appear to have higher ratio, of latewood to earlywood than that in normal trees. In the hardwood species studied, mesomorphy of vessel elements is lower in dwarfs than that in normal trees. It can be concluded that this dwarf growth occurs as a result of extremely slow growth by environmental stress such as water deficiency.ciency.

• Journal of Forest and Environmental Science
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• v.31 no.1
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• pp.47-54
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• 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.

• Journal of Korean Society on Water Environment
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• v.30 no.1
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• pp.31-43
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• 2014

Recently, Andong Reservoir and Imha Reservoir located in Nakdong River basin (Korea) are being connected by a tunnel (length 2km, diameter 5.5m) for a conjunctive use. The objectives of this study were to construct a two dimensional(2D) laterally-averaged model for two reservoirs, and examine the effects of connection on the water transportation and temperature stratification in the reservoirs. The 2D models for each reservoir were calibrated using field data obtained in 2006, and applied to the linked system for the year of 2002 when a severe flood intruded into Imha Reservoir during the typhoon Rusa. Simulation results showed that 364 million $m^3$ of water can be conveyed from Imha to Andong, while 291 million $m^3$ of water from Andong to Imha after connection. It resulted in 1.38 m increase of annual averaged water level in Andong Reservoir, whereas 3.75 m decrease in Imha Reservoir. The structures of thermal stratification in both reservoirs were influenced in line with the flow exchanges. In Andong Reservoir, the location of thermocline moved upward about 10 m compared to an independent operation. The results imply that the persistent turbidity issue of Imha Reservoir might be shifted to Andong Reservoir during a severe flood event after connection.