• Korean Journal of Remote Sensing
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• v.20 no.1
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• pp.39-46
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• 2004

The generalized Rayleigh-Gans (GRG) approximation is usually used to compute the scattering amplitudes of leaves smaller or comparable to a wavelength, while the physical optics (PO) approach with the resistive sheet approximation is commonly used for leaves larger or comparable to the wavelength. In this paper, the scattering amplitudes of an elliptical leaf are computed using those theoretical scattering models (GRG and PO) at different frequencies. The accuracies of the analytical models for microwave scattering from deciduous leaves are investigated by comparison with the precise estimation by the method of moment (MoM). It was found that both the PO approach and the GRG approximation can be used alternatively for computing the scattering matrices of natural deciduous leaves at P-, L-, C- and X-band frequencies.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.316-318
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• 2003

An eigen-analysis of the coherency matrix provides the polarimetric scattering mechanisms with the matrix characterizing parameters. In this paper, the coherency matrices of deciduous and coniferous vegetation are calculated using the analytical method. The Generalized Rayleigh-Gans approximation is used to model backscattering from distributed coniferous and deciduous leaves. The characteristics of eigen-parameters of simulated coherency matrix for deciduous and coniferous leaves with respect to the leaf shapes and orientations are illustrated.

• Journal of Korean Society of Forest Science
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• v.89 no.1
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• pp.41-48
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• 2000

Mass loss and dynamics of mineral nutrient during decomposition of deciduous leaves and 3 species of needles were investigated for 38 months from October in 1992 to November in 1995 in Kwangneung, Korea. After 38 months, the remaining mass of deciduous leaves, Pinus koraiensis, Pinus rigida and Abies holophylla was 16.2%, 29.8%, 33.5% and 53.9%, respectively. The decay rate (k) of deciduous leaves, Pinus koraiensis, Pinus rigida and Abies holophylla was 0.61, 0.40, 0.37, $0.21yr^{-1}$, respectively. The lowest decay rate in fir needle might be, in part, due to low N concentration. N concentration of the decomposing litter increased during the experimental period except for P. rigida. Deciduous leaves showed a short immobilization period during the early stage of decomposition, and big-cone pine and pitch pine had no immobilization period. However, there was no net N mineralization in fir litter. P increased during the experimental period for all litter. Except for deciduous leaves, there was no net mineralization period. In case of deciduous leaves, however, remaining P after 38 months was 53% of the initial P capital. Remaining cations of the decomposing litter after 38 months were lower than those of initial contents.

• Proceedings of the KSRS Conference
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• 2004.10a
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• pp.586-589
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• 2004

A numerical algorithm using the Method of Moments (MoM) is introduced to compute precisely the scattering matrices of very thin deciduous leaves in this paper. At first, a dyadic Green's function was formulated and an integral equation for a volumetric current distribution in a lossy dielectric body. Then, the MoM was applied to the scattering problem with a specific technique to handle the numerical poles. The accuracy of the numerical technique was verified by examining the technique with various ways, and used to examine the validity regions of the classical analytical models.

• Journal of Plant Biology
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• v.19 no.4
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• pp.107-110
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• 1976

This study was carried out to investigate lead contamination in the leaves of roadside trees and the cause of yellow-brown symptom of leaves in Jinju and Daegu city. After the leaves were collected and dried in 105$^{\circ}C$ drying oven from September to October in 1974, the samples were used for analysis of the lead contents in 1976. The roadside trees in the two cities were mostly the four kinds of Ginkgo biloba L., Thuja orientalis L., Platanus orientalis L. var. acerifolia AIT. and Prunus pseudo-cerasus $LINDL{\times}Prunus$ subhirtella MIQ. The lead contents in the leaves of roadside trees in Daegu city was higher than that of Jinju city. The lead contamination of the evergreen trees of roadside was higher than that of the deciduous trees. In Jinju city the site of the highest contents of lead in the leaves was revealed with Jinju station(0.73ppm), the next site was revealed with the road(0.16ppm) between Namgang bridge and Jinju middle school, and the lowest site was generally beside the roads of suburbs (0.07ppm). Because of the low contents of lead in the leaves, it was found that the yellow-brown symptoms of leaves were not caused by the lead toxicity.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2002.09a
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• pp.200-202
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• 2002

This study was for comparisons of transitional element concentrations from the two different soil, serpentinite(SP) and granite area(GR), Kwangcheon and Hongseong area. Soils were collected by soil depths (10, 20 and 30cm) from the sites selected In the plant species(coniferous and deciduous species). In the soils, the SP was high in the Cr, Mn, Fe, Co, Ni and Zn concentrations, while the GR was high in the Cu, As, Sc and V. With the soil depths, the elements had high solubility, such as Cr, Co and Ni concentrations, were high in the SP, while the other elements were not clear. For the both species, the SP was high in the root and bolebark, while in the GR, not clear. Coniferous species in the same soil types, was higher than the deciduous In most elements. The more with increasing ages, the more with element accumulation in most plant parts except leaves. Comparisons between the soils and plant species, in the case of the element contents within the soils, the plant species in the same sites was similar trend. especially, clear in the SP

• Journal of Ecology and Environment
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• v.31 no.3
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• pp.207-211
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• 2008

We investigated the leaf demography of a temperate woody liana, Akebia trifoliata, in a temperate forest in Japan, Akebia is semi-evergreen: some leaves are shed before winter, while others remain through the winter. Previous studies of semi-evergreen species found that variation in leaf life span was caused by variation in the timing of leaf emergence, Leaves that appeared just before winter over-wintered, while leaves appearing earlier were shed, However, it is unclear whether leaves of the same cohort (i.e., leaves that appear at the same time within a single site) show variation in life span under the effect of strong seasonality. To separate variation in life span among the leaves in each cohort from variation among cohorts, we propose a new method - the single leaf diagram, which shows the emergence and death of each leaf. Using single leaf diagrams, our study revealed that Akebia leaves within a cohort showed substantial variation in life span, with some over-wintering and some not. In addition, leaves on small ramets in the understory showed great variation in life span, while leaves on large ramets, which typically reach higher positions in the forest canopy, have shorter lives, As a result, small ramets were semi-evergreen, whereas large ramets were deciduous, The longer lives of leaves on small ramets can be interpreted as a shade-adaptive strategy in understory plants.

• Journal of Ecology and Environment
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• v.37 no.2
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• pp.91-97
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• 2014

Little is known about how the increased porosity of a deciduous windbreak, which results from loss of leaves, influences wind speed reduction. We hypothesized that, with loss of foliage, the wind speed reduction effectiveness of a deciduous windbreak decreases on near leeward side but not on further leeward side and that wind speed recovers faster in the full foliage season than in other seasons. During summer, autumn, and winter (full, medium, and non-foliage season, respectively), we observed wind speed and direction around a deciduous windbreak in a traditional Korean village on windward and near and further leeward sides (at -8H, 2H, and 6H; H = 20 m, a windbreak height). We used a linear mixed effects model to determine that the relative wind speed reduction at 2H significantly decreased from 83% to 48% ($F_{2,111.97}=73.6$, P < 0.0001) with the loss of foliage. However, the relative wind speed reduction at 6H significantly increased from 26% to 43% ($F_{2,98.54}=18.5$, P < 0.0001). Consequently, wind speed recovery rate between 2H and 6H in summer was two times higher than in autumn and ten times higher than in winter ($F_{2,102.93}=223.1$, P < 0.0001). These results indicate that deciduous windbreaks with full foliage seem to induce large turbulence and increase wind speed recovery rate on leeward side. Our study suggests that further research is needed to find the optimal foliage density of a deciduous windbreak for maximizing windbreak effectiveness regardless of seasonal foliage changes.

• Journal of Environmental Science International
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• v.21 no.1
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• pp.89-96
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• 2012

The rate of photosynthesis (A) of leaves from 10 plant species (6 evergreen and 4 deciduous) of the family Fagaceae was measured using a portable photosynthesis analyzer, to examine which species take up $CO_2$ most efficiently. Of the evergreen species, the photosynthetic rate of Castanopsis cuspidata var. sieboldii was highest, and remained above 82.1~106.4 ${\mu}mol\;kg^{-1}s^{-1}$ from July to November. Of the deciduous species, the photosynthetic rate of Quercus acutissima was higher than that of the other three species, and remained high at 83.5~116.6 ${\mu}mol\;kg^{-1}s^{-1}$ from September to November. The photosynthetic rate of the 10 species was positively correlated with stomatal conductance (gs) and transpiration rate (E). However, there was no correlation between photosynthetic rate and intercellular $CO_2$ concentration ($C_i$), although there was a positive correlation just in three species (Q. gilva, Q. acutissima and Q. glauca). These results suggest that the $CO_2$ fixation capacity of C. cuspidata var. sieboldii, an evergreen species, and Q. acutissima, a deciduous species, is significantly higher than that of the other species examined, and that photosynthesis is regulated by both stomatal conductance and transpiration. Therefore, C. cuspidata var. sieboldii and Q. acutissima may be valuable for the evaluation of carbon uptake in urban green spaces as well as in afforested areas.

• Journal of Environmental Science International
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• v.29 no.2
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• pp.123-132
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• 2020

Seasonal changes in the CO₂ fixation rate and water-use efficiency in the leaves of six evergreen and two deciduous broad-leaved tree species on Jeju Island, Korea, were measured using a portable photosynthesis analyzer, to identify which species are most efficient in taking up CO₂ from the air. The CO₂ fixation rate was high in the deciduous species in spring and summer and decreased in fall, whereas it was high in the evergreen species in summer and fall and decreased in winter. The rate remained high in the deciduous tree Prunus yedoensis from spring to fall (> 7.1 μmol CO₂/m₂/s) and in two evergreen trees, Castanopsis cuspidata var. sieboldii and Cinnamomum camphora, in summer and fall (7.0 9.9 μmol CO₂/㎡/s). Therefore, these tree species fix atmospheric CO₂ effectively. The water-use efficiency was higher in evergreen species than in deciduous species regardless of the season. Exceptionally, it was high in the deciduous species Zelkova serrata in spring and summer (> 100 μmol CO₂/mol H₂O), suggesting that Z. serrata is a useful tree for dry conditions due to its tolerance of water stress. The regressions of the CO₂ fixation rate versus the evaporation rate and stomatal conductance were linear and non-linear, respectively. This suggests that the stomatal activity of leaves plays an important part in CO₂ fixation of plants. In conclusion, C. cuspidata var. sieboldii, C. camphora, and P. yedoensis should be planted along roads or in urban spaces for the greening of cities and mitigation of CO₂ concentrations in the air.