• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.3 no.3
• /
• pp.45-76
• /
• 2000

The purposes of this study were to investigate and understand the present status of various types of "deserts", such as sand desert, gravel desert, rock desert, earth desert, salt desert, desert, rocky desert, gobi desert, sandy desert, clay desert, etc., and the general countermeasures for the combating "desertification" "desertization", and to develop the technologies on the revegetation and restoration for the combating desertification in China. The methods of this study were mainly composed of field surveys on the several experimental sites and research institutes related to combating desertification in China, and examinations on the various technologies for the combating desertification at the Daxing Experimental Station of Beijing Forestry University. The conclusion from this study may be summarized as follows; 1. Status and tendency of desertification in China : China is one of the countries seriously threatened by desertification. Desertification affected areas in China are mainly distributed in arid, semi-arid and dry sub-humid areas in China, covering the most regions of the Northeast China (eastern region of Inner-Mongolia), the northern part of the North China (middle and western region of Inner-Mongolia, Shaanxi, Ningsha, Gansu) and the western part of the Northwest China (Xinzang, Qinghai, Xizang). The total area affected by desertification in China is approximately 2.622 million $km^2$. It covers 27.3% of the total territory of China. Until recently, it is estimated that the annual spreading ratio of desertification in China is 2,460 $km^2$. Therefore, desertification is mostly serious problems facing to the Chinese people. 2. The causes and environmental effect of desertification : The desertification in China is mainly caused by compound factors, including natural condition and human activities. In China, the desertification is started by the decrease of precipitation, continuous dry and drought, strong wind, wind and water erosion, land degradation and loss of natural vegetation caused by climate variation, and accelerated by the human activities, such as over-cultivating, over-grazing, over-cutting of woods, irrational use of water resources. Because desertification has affected the geographical features, soil nutrients contents, salinity, vegetation coverage and the functions of ecosystem, the environmental deteriorations in the desertification affected areas are very seriously. 3. The fundamental strategies of combating desertification in China are the increase of education and awareness of people through various mass media, the revision of laws to guarantee operation of Desertification Combating Law and to improve many relating laws and regulations, the application of advanced technologies and training of experts, the establishment of discriminative policies, and increasing arrangement of budget-investment, and so on. China, as a signed country in UNCCD, has made efforts for the combating desertification. Korea is also signed country in UNCCD, so we should play an important role in the desertification combating projects of China for the northest asia and global environmental conservation as well as environmental conservation of Korea.

• Korean Journal of Ecology and Environment
• /
• v.53 no.1
• /
• pp.31-45
• /
• 2020

The biological indices based on the community structure with species richness and/or abundance are commonly used to assess aquatic ecosystem health. Meanwhile, recently functional traits-based approach is considered in ecosystem health assessment to reflect ecosystem functioning. In this study, we developed a database of biological traits for 136 taxa consisting of major stream insects (Ephemeroptera, Plecoptera, Trichoptera, Coleoptera, and Odonata) collected at Korean streams on the nationwide scale. In addition, we obtained environmental variables in five categories (geography, climate, land use, hydrology and physicochemistry) measured at each sampling site. We evaluated the relationships between community indices based on taxonomic diversity and functional diversity estimated from biological traits. We classified sampling sites based on similarities of their environmental variables and evaluated relations between clusters of sampling sites and diversity indices and biological traits. Our results showed that functional diversity was highly correlated with Shannon diversity index and species richness. The six clusters of sampling sites defined by a hierarchical cluster analysis reflected differences of their environmental variables. Samples in cluster 1 were mostly from high altitude areas, whereas samples in cluster 6 were from lowland areas. Non-metric multidimensional scaling (NMDS) displayed similar patterns with cluster analysis and presented variation of taxonomic diversity and functional diversity. Based on NMDS and community-weighted mean trait value matrix, species in clusters 1-3 displayed the resistance strategy in the life history strategy to the environmental variables whereas species in clusters 4-6 presented the resilience strategy. These results suggest that functional diversity can complement the biological monitoring assessment based on taxonomic diversity and can be used as biological monitoring assessment tool reflecting changes of ecosystem functioning responding to environmental changes.

• Korean Journal of Environmental Biology
• /
• v.29 no.1
• /
• pp.52-60
• /
• 2011

Today, the weather is changing continually, due to the progress of global warming. As the weather changes, the habitats of different organisms will change as well. It cannot be predicted whether or not the weather will change with each passing day. In particular, the biological distribution of the areas climate change affects constitutes a major factor in determining the natural state of indigenous plants; additionally, plants are constantly exposed to rhizospheric microorganisms, which are bound to be sensitive to these changes. Interest has grown in the relationship between plants and rhizopheric microorganisms. As a result of this interest we elected to research and experiment further. We researched the dominant changes that occur between plants and rhizospheric organisms due to global warming. First, we used temperature as a variable. We employed four different temperatures and four different sites: room temperature ($27^{\circ}C$), $+2^{\circ}C$, $+4^{\circ}C$, and $+6^{\circ}C$. The four different sites we used were populated by the following species: Pinus deniflora, Pinus koraiensis, Quercus acutissima, and Alnus japonica. We counted colonies of these plants and divided them. Then, using 16S rRNA analysis we identified the microorganisms. In conclusion, we identified the following genera, which were as follows: 10 species of Bacillus, 2 Enterobacter species, 4 Pseudomonas species, 1 Arthrobacter species, 1 Chryseobacterium species, and 1 Rhodococcus species. Among these genera, the dominant species in Pinus deniflora was discovered in the same genus, but a different species dominated at $33^{\circ}C$. Additionally, that of Pinus koraiensis changed in both genus and species which changed into the Chryseobacrterium genus from the Bacilus genus at $33^{\circ}C$.

• Korean Journal of Environment and Ecology
• /
• v.32 no.1
• /
• pp.30-38
• /
• 2018

The purpose of this paper is to provide reference data about propagation, restoration, and preparation of policy of endangered Sarcandra glabra (Thunb.) Nakai by investigating growth response and variation of ecological niche breadth according to moisture and nutrient under the condition of elevated $CO_2$ concentration and elevated temperature. We divided the investigation into the controlled group and treated group (elevated $CO_2$ concentration and elevated temperature) and then varied the moisture and nutrient treatment for testing. The results showed that the ecological niche breadth was wide at moisture and nutrient gradients of 0.899 and 0.844, respectively, under control. Also, the ecological niche breadth regarding the moisture and nutrient gradients under treatment simulating global warming was wider as 6.60% and 2.09%, respectively. Therefore, moisture and nutrient will not be the restriction factors concerning the growth of Sarcandra glabra under continued global warming. However, it will be advisable to specify the nutrient content condition in the soil to be 10% for population restoration when growing Sarcandra glabra in the green house which is not affected by external environment since the studies of rearing reaction reported that Sarcandra glabra prefer 10% of nutrient content than 0-5%. Furthermore, it is necessary to protect evergreen broad-leaved forest where is the natural habitat of Sarcandra glabra that has relatively high nutrient content.

• Journal of Korean Society of Forest Science
• /
• v.85 no.1
• /
• pp.107-119
• /
• 1996

To understand vegetation changes along environmental gradients in the natural forests in the east side of the Cascade Range in Washington state, USA, line transects were used to sample six different forest environments in the Wenatchee National Forest in the north-facing and south-facing sites at 975, 1280 and 1700m elevation. Data were analyzed using ordination by detranded correspondence analysis. Pseudotsuga menziesii was found as one of the dominant species on all the six sites regardless of elevation or aspect, while Pinus ponderosa was dominant on south slopes only. Abies grandis and A. lasiocarpa were dominant species on north slopes at elevations of 1280 and 1700m, respectively. Moisture, as it related to aspect, was identified as one of the most important environmental gradients for explaining the variation of vegetation types. On north-facing slopes, compared to south-facing slopes, where moisture was not as limiting and canopies could grow denser, probably, elevation or competitive interaction was more important. Species diversity tended to decrease with increasing environmental severity, with south slopes having less diversity than north slopes due to extended water stress and harsher temperature extremes on south slopes. The age structure on north-facing and south-facing slopes was different. Light intensity, moisture and climate were different between these two slopes. Large scale disturbances(e.g., big fire or insects) were major causes in changing age structure. Younger trees showed a closer relationship between size and age than adult trees. DBH values of shade intolerant species in south-facing slope were bigger than those of north-facing slope, which suggested that aspect of stands be the most important factor for age and size.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.16 no.3
• /
• pp.199-212
• /
• 2014

The physiological responses of three common temperate species, Pinus densiflora, Fraxinus rhynchophylla, Sorbus alnifolia to elevated $CO_2$ was investigated using open top chambers with different $CO_2$ concentrations. Morphological (stomatal size, density and area) and physiological characteristics (maximum rates of photosynthesis, carboxylation and electron transport) were compared among trees grown under ambient, ambient ${\times}1.4$ (~550 ppm) and ambient ${\times}1.8$ (~700 ppm) $CO_2$ concentrations for last four years. Morphological responses were different among species. F. rhynchophyllar increased their stomatal size and S. alnifolia had higher stomatal density under elevated $CO_2$ than ambient. Stomatal area decreased in P. densiflora, whereas it increased in S. alnifolia. However, the maximum photosynthesis rate increased in all species up to 43.5% by S. alnifolia under elevated $CO_2$ and the enhancement increased with time. Even with four years of exposure to elevated $CO_2$, there was no sign of acclimation in the maximum carboxylation rate and the maximum electron transport rates in all species. Especially, S. alnifolia even showed the temporary increase of photosynthetic capacities in spring, when leaf nitrogen concentration was high with new leaf development. There was no significant differences in diameter growth rate in any species due to high variation in their tree sizes, however accumulated diameter and biomass for four years showed significantly increment in all species under elevated $CO_2$. For example, S. alnifolia showed 59% increase in diameter at the ambient ${\times}1.8$ (~700 ppm) compared to ambient.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.18 no.4
• /
• pp.221-232
• /
• 2016

Models to estimate solar radiation have been used because solar radiation is measured at a smaller number of weather stations than other variables including temperature and rainfall. For example, solar radiation has been estimated using the Angstrom-Prescott (AP) model that depends on two coefficients obtained empirically at a specific site ($AP_{Choi}$) or for a climate zone ($AP_{Frere}$). The objective of this study was to identify the coefficients of the AP model for reliable estimation of solar radiation under a wide range of spatial and temporal conditions. A global optimization was performed for a range of AP coefficients to identify the values of $AP_{max}$ that resulted in the greatest degree of agreement at each of 20 sites for a given month during 30 years. The degree of agreement was assessed using the value of Concordance Correlation Coefficient (CCC). When $AP_{Frere}$ was used to estimate solar radiation, the values of CCC were relatively high for conditions under which crop growth simulation would be performed, e.g., at rural sites during summer. The statistics for $AP_{Frere}$ were greater than those for $AP_{Choi}$ although $AP_{Frere}$ had the smaller statistics than $AP_{max}$ did. The variation of CCC values was small over a wide range of AP coefficients when those statistics were summarized by site. $AP_{Frere}$ was included in each range of AP coefficients that resulted in reasonable accuracy of solar radiation estimates by site, year, and month. These results suggested that $AP_{Frere}$ would be useful to provide estimates of solar radiation as an input to crop models in Korea. Further studies would be merited to examine feasibility of using $AP_{Frere}$ to obtain gridded estimates of solar radiation at a high spatial resolution under a complex terrain in Korea.

• Korean Journal of Remote Sensing
• /
• v.28 no.2
• /
• pp.215-226
• /
• 2012

NASA MODIS GPP provides a useful tool to monitor global terrestrial vegetation productivity. Two major problems of NASA GPP in regional applications are coarse spatial resolution ($1.25^{\circ}{\times}1^{\circ}$) of DAO meteorological data and cloud contamination of MODIS FPAR product. In this study, we improved the NASA GPP by using enhanced input data of high spatial resolution (3 km${\times}$3 km) WRF meteorological data and cloud-corrected FPAR over the North Korea. The improved GPP was utilized to investigate characteristics of GPP interannual variation and spatial patterns from 2000 to 2008. The GPP varied from 645 to 863 $gC\;m^{-2}\;y^{-1}$ in 2000 and 2008, respectively. Mixed forest showed the highest GPP (1,076 $gC\;m^{-2}\;y^{-1}$). Compared to NASA GPP (790 $gC\;m^{-2}\;y^{-1}$);FPAR enhancement increased GPP (861) but utilization of WRF data decreased GPP (710). Enhancements of both FPAR and meteorological input resulted in GPP increase (809) and the improvement was the greatest for mixed forest regions (+10.2%). The improved GPP showed better spatial heterogeneity reflecting local topography due to high resolution WRF data. It is remarkable that the improved and NASA GPPs showed distinctly different interannual variations with each other. Our study indicates improvement of NASA GPP by enhancing input variables is necessary to monitor region-scale terrestrial vegetation productivity.

• Membrane Journal
• /
• v.20 no.3
• /
• pp.249-258
• /
• 2010

In this study, we tried to observe the permeation on the single $O_2$, $CF_4$ and $SF_6$ gas using a PSF (polysulfone), PC (tetra-bromo polycarbonate) and PI (polyimide) hollow fiber membranes. We also observed the permselectivity on the $O_2/SF_6$ and $CF_4/SF_6$. According to the results of single gases permeation for different pressures, PSF membrane has the highest $O_2$ permeation of 37.5 GPU and PC membrane has the highest $SF_6$ permeation of 2.7 GPU and the highest $CF_4$ permeation of 2.5 GPU at 1.1 MPa. According to the results of single gases permeation for different temperatures, PSF membrane has the highest permeation of $O_2$ at $45^{\circ}C$ and PC membrane has the highest permeation of $SF_6$ and $CF_4$ at $25^{\circ}C$. From the result of $O_2/SF_6$ and $CF_4/SF_6$ permselectivity for different pressures and temperature, the highest permeation and the lowest permselectivity were observed in the PSF and PC membrane. On the contrary, the lowest permeation and the highest permselectivity was observed in the PI membrane.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.28 no.6
• /
• pp.256-268
• /
• 2016

This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2015. It is intended to understand the status of current research in the areas of heating, cooling, ventilation, sanitation, and indoor environments of buildings and plant facilities. Conclusions are as follows. (1) The research works on the thermal and fluid engineering were carried out in the areas of flow, heat and mass transfer, cooling and heating, and air-conditioning, the renewable energy system and the flow inside building rooms. Research issues dealing with air-conditioning machines and fire and exhausting smoke were reduced. CFD seems to be spreading to more research areas. (2) Research works on heat transfer area were carried out in the categories of heat transfer characteristics, pool boiling and condensing heat transfer and industrial heat exchangers. Researches on heat transfer characteristics included the economic analysis of GHG emission, micro channel heat exchanger, effect of rib angle on thermal performance, the airside performance of fin-and-tube heat exchangers, theoretical analysis of a rotary heat exchanger, heat exchanger in a cryogenic environment, the performance of a cross-flow-type, indirect evaporative cooler made of paper/plastic film. In the area of pool boiling and condensing, the bubble jet loop heat pipe was studied. In the area of industrial heat exchangers, researches were performed on fin-tube heat exchanger, KSTAR PFC and vacuum vessel at baking phase, the performance of small-sized dehumidification rotor, design of gas-injection port of an asymmetric scroll compressor, effect of slot discharge-angle change on exhaust efficiency of range hood system with air curtain. (3) In the field of refrigeration, various studies were carried in the categories of refrigeration cycle, alternative refrigeration/energy system, system control. In the refrigeration cycle category, a cold-climate heat pump system, $CO_2$ cascade systems, ejector cycles and a PCM-based continuous heating system were investigated. In the alternative refrigeration/energy system category, a polymer adsorption heat pump, an alcohol absorption heat pump and a desiccant-based hybrid refrigeration system were investigated. In the system control category, turbo-refrigerator capacity controls and an absorption chiller fault diagnostics were investigated. (4) In building mechanical system research fields, eighteen studies were reported for achieving effective design of the mechanical systems, and also for maximizing the energy efficiency of buildings. The topics of the studies included energy performance, HVAC system, ventilation, and renewable energies, piping in the buildings. Proposed designs, performance tests using numerical methods and experiments provide useful information and key data which can improve the energy efficiency of the buildings. (5) The field of architectural environment was mostly focused on indoor environment and building energy. The main researches of indoor environment were related to the user and location awareness technology applied dimming lighting control system, the lighting performance evaluation for light-shelves, the improvement evaluation of air quality through analysis of ventilation efficiency and the evaluation of airtightness of sliding and LS window systems. The subjects of building energy were worked on the energy saving estimation of existing buildings, the developing model to predict heating energy usage in domestic city area and the performance evaluation of cooling applied with economizer control. The studies were also performed related to the experimental measurement of weight variation and thermal conductivity in polyurethane foam, the development of flame spread prevention system for sandwich panels, the utilization of heat from waste-incineration facility in large-scale horticultural facilities.