• 한국신재생에너지학회:학술대회논문집
• /
• 2005.06a
• /
• pp.448-451
• /
• 2005

This paper presents the methodology to analyze flow duration characteristics and performance prediction for small hydro power(SHP) plants and its application. The flow duration curvecan be decided by using monthly rainfall data at the most of the SHP sites with no useful hydrological data. It was proved that the monthly rainfall data can be characterized by using the cumulative density function of Weibull distribution and Thiessen method were adopted to decide flow duration curve at SHP plants. And, the performance prediction has been studied and development. One SHP plant was selected and performance characteristics was analyzed by using the developed technique. Primary design specfications such as design flowrate, plant capacity, operational rate and annual electricity production for the SHP plant were estimated. It was found that the methodology developed in this study can be a useful tool to predict the performance of SHP plants and candidate sites in Korea.

• Journal of Ecology and Environment
• /
• v.33 no.3
• /
• pp.253-260
• /
• 2010

It has been well established that leaf longevity is linked to the carbon economy of plants. We used this relationship to predict leaf lifetime carbon gains from leaf lifespan, and estimated the gross primary production (GPP) of a young deciduous forest of Japanese beech (Fagus crenata) located in central Japan. The light-saturated photosynthetic rates of the leaves were measured repeatedly during the growing season. We used the leaf lifespan to calculate the conversion coefficient from the light-saturated photosynthetic rate into the realized leaf lifetime carbon gain under field conditions. The leaf turnover rate was estimated using litter traps. GPP was estimated as the product of lifetime carbon gain per unit of leaf mass, and the annual leaf turnover rate. The GPP of the forest in 2007 was estimated to be $1.2{\times}10^3gCm^{-2}y^{-1}$, which was within the range of previously reported GPP values of beech forests in Japan, and was close to the GPP of a European beech forest, as estimated by eddy flux measurements.

• Journal of Wetlands Research
• /
• v.12 no.1
• /
• pp.15-22
• /
• 2010

We measured net primary productivity, annual accumulation of organic carbon and leaf decomposition of Salix community in the flood plain of the Han River and the Nakdong River. Net primary productivity, annual accumulation of organic carbon of the Salix community were 22.5ton/ha/yr(16.7ton/ha/yr-31.2ton/ha/yr) and 9.7ton C/ha/yr(7.5ton C/ha/yr-14.0ton C/ha/yr) respectively, which showed the highest values among the woody plant communities reported in the Korea. It means that planting Salix in the flood plain of the river is the best way to remove carbon dioxides. The faster leaf decomposition occurred around, under and the herb of Salix community in order. Leaf decomposition rate of Salix was higher than that of mesophytes, but lower than that of hydrophytes.

• Korean Journal of Ecology and Environment
• /
• v.34 no.3 s.95
• /
• pp.166-174
• /
• 2001

The autochthonous and allochthonous organic carbon loading were measured in Lake Soyang, to estimate the amount of carbon loading into the lake and the contribution of their sources to tile lake's carbon loading. Autochthonous carbon loading was estimated from phytoplankton primary production with the extracellular organic carbon (EOC). Allochthonous loading was determined by measuring dissolved organic carbon (DOC) and particulate organic carbon (POC) concentration in the main inflowing Soyang River. Both autochthonous and allochthonous organic carbon loading were high during the svmmer, from July to September, and accounted for 43.2% and 71.7% of the annual loading, respectively. Primary productivity was elevated up to $1,000\;mgC\;m^{-2}\;d^{-1}$ during summer and lowest in winter. EOC production from phytoplankton was also large in summer, resulting in a high DOC concentration in the lake water. Primary production of phytoplankton and allochthonous organic matter loading from the watershed contributed to 53.6% and 46.4% of total loading, respectively. The EOC production accounted far $4.4{\sim}21.2%$ of POC primary production, implying that EOC production of phytolankton must be considered in estimation of primary production.

• Ocean and Polar Research
• /
• v.23 no.4
• /
• pp.395-400
• /
• 2001

A time-series sediment trap was deployed at 1,034 m water depth in the eastern Bransfield Strait from December 25, 1998 to December 24, 1999. About 99 % of total mass fluxes were observed during the austral summer and fall (January, February, and March). The annual total mass flux was $49.2g\;m^{-2}$. Biogenic materials including biogenic silica, organic matter, and carbonate accounted for about 67% of total particle flux, and lithogenic materials contributed about 29%. Biogenic silica was the most dominant (42% of the total flux) in these components. The next most important biogenic component was organic matter, comprising 24% of total mass flux. Calcium carbonate contributed a small fraction of total mass flux, only 0.6%. The annual organic carbon flux was $5.2g\;C\;m^{-2}$ at 1,034m water depth. The annual primary production was estimated to be $21.6g\;C\;m^{-2}$ at the sediment trap site, which seems to be highly underestimated. About 5.5% of the surface water production of organic carbon sinks below 1,034m water depth.

• The Korean Journal of Ecology
• /
• v.24 no.6
• /
• pp.377-380
• /
• 2001

Herbivory is an important selective forces on plants by reducing the ability of the plant to compete with its neighbors and to produce offspring. Oak nut weevil(Mechoris ursulus Roelofs) females lay eggs in unmatured acorns and cut off the branch of oviposited acorns. To investigate the influences of branch-cutting behavior of oak nut weevils on oak production, we surveyed the horizontal and vertical distribution ranges of damaged oaks and depth of sites of overwintering larvae and quantified the amounts of biomass and acorn removed by the weevils on deciduous oak species. All of the endemic oak species in Korea were damaged by oak nut weevils in all of the study sites including Mt. Halla and Mt. Seorak. The upper limit of vertical distribution of damaged oaks by the weevils raried from 700 m to 900 m. Mostly their larvae were found in soil from 8.1 cm to 10.0 cm depth in winter. Percentage of annual net primary productivity($720g{\cdot}m^{-2}{\cdot}day^{-1}$) of oak species removed by the weevils was about 7%, which is higher than the percentage removed by all the herbivores in typical temperate forest(5%) and equivalent to that by all the herbivores in tropical forest. The predation percentage of annual acorn production by oak nut weevil was 27% in Q. mongolica and 33% in Q. acutissima. This results indicate that the branch-cutting behavior of oak nut weevil may be the most important factor regulating oak population and affecting other predators dependent on acorns.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
• /
• v.3 no.3
• /
• pp.189-196
• /
• 1999

The community structure, phytomass, and primary productivity in Thuja orientalis stands on a limestone area located in Maepo-up, Chungbuk province in Korea were estimated quantitatively. Seven species including a small proportion of Quercus dentata were identified in the tree layer, 26 species including Ulmus macrocarpa in the shrub layer, and 79 species including Carex lnceolata in the herb layer of the Thuja stands. The vertical distribution of the fine root phytomass exhibited a power functional decrease relative to the soil depth. The seasonal changes in the fine root phytomass at a soil depth of 5 cm were closely related to the pecipitation in the study area. The productivity of the stand of stems, branches, leaves, and roots were 10.72, 0.82, 0.45 and 6.46 ton DM. $ha^{-1}$ .$yr^{-1}$, respectively. The Thuja stand had a high foliage(25%) and low rate of production per unit of foliage. The annual turnover rate of the fine roots int he Thuja stand was 6.71 $yr^{-1}$. The net primary production of the overstory including the understory was estimated at 19.48 ton DM.$ha^{-1}$.$yr^{-1}$ including an underground section of 6.46 ton DM.$ha^{-1}$.$yr^{-1}$(33%). The allocation ratio of net production to root was lower in the limestone Thuja communities than at the nearby non-limestone ones, whereas the production efficiency to leaf weight was higher in the limestone communities. These results would seem to indicate that the limited production capacity is due to the calcium toxicity and low availability of iron and phosphorus in a limestone soil with a high pH, calcium, and bicarbonate content with a strategy for survival in a hostile habitat.

• Proceedings of The Korean Society of Agricultural and Forest Meteorology Conference
• /
• 2005.09a
• /
• pp.41-44
• /
• 2005

• Journal of Korean Society of Forest Science
• /
• v.71 no.1
• /
• pp.33-39
• /
• 1985

This study was performed to investigate the damage to the primary production of Pinus thunbergii forest from air pollution around the Yeochon Industrial Estate. The data were observed at 6 sites in the vicinity of the above area. The vitality of pine trees and the accumulation of the soluable sulfur and the fluorine were analyzed. Their value was generally increased near the source of air pollutants. The biomass density and annual net production were $1.01kg/m^3$, 5.90 t/ha/yr in the stand 4 respectively and $0.66kg/m^3$, 0.32t/hr/hr in the stand 3 respectively. The net assimilation rate was 0.4 - 1.6 kg/kg/yr and the efficiency of leaf to produce stem was 0.3 - 1.3 kg/kg/yr. The annual growth percentage of volume was 16.0% at the slightly damaged area and 4.0% at the severly damaged area. The maximum mean annual increment per tree was $0.0040m^3$ and $0.0008m^3$ in same order.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.3 no.4
• /
• pp.220-237
• /
• 2001

Over the 20th century global temperature increase has been 0.6$^{\circ}C$. The globally averaged surface temperature is projected to increase by 1.4 to 5.8$^{\circ}C$ over the period 1990 to 2100. Nearly all land areas will have higher maximum temperature and minimum temperature, and fewer cold days and frost days. More intense precipitation events will take plate over many areas. Over most mid-latitude continental interiors will have increased summer continental drying and associated risk of drought. By 2100, if the annual surface temperature increase is 3.5$^{\circ}C$, we will have 15.9$^{\circ}C$ from 12.4$^{\circ}C$ at present. Also the annual precipitation will range 1,118-2,447 mm from 972-1,841 mm at present in Korea. Consequently the average crop periods for summer crops will be 250 days that prolonged 32 days than at present. In the case of gradual increase of global warming, an annual crop can be adapted to the changing climate through the selection of filial generations in breeding process. The perennial crops such as an apple should be shifted the chief producing place to northern or high latitude areas where below 13.5$^{\circ}C$ of the annual surface temperature. If global warming happens suddenly over the threshold atmospheric greenhouse gases, then all ecosystems will have tremendous disturbance. Agricultural land-use plan, which state that farmers decide what to plant, based on their climate-based advantages. Therefore, farmers will mitigate possible negative imparts associated with the climate change. The farmers will have application to use agricultural meteorological information system, and agricultural long-range weather forecast system for their agroecosystems management. The ideal types of crops under $CO_2$ increase and climate change conditions are considered that ecological characteristics need indispensable to accomplish the sustainable agriculture as the diversification of genetic resources from yield-oriented to biomass-oriented characteristics with higher potential of $CO_2$ absorption and primary production. In addition, a heat-and-cold tolerance, a pest resistance, an environmental adaptability, and production stability should be also incorporated collectively into integrated agroecosystem.