• KOREAN JOURNAL OF CROP SCIENCE
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• v.39 no.3
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• pp.262-269
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• 1994

This study was conducted to clarify high yielding factors of F$_1$ hybrids in terms of the growth characteristics, canopy structure, nitrogen content and nitrogen profile in the canopy. Varieties used in this study were four hybrid rices showing different heterosis in grain yield and their parents. Varieties of Japonica were Reimei (maintainer), TP 681 and TP 1278(restorers), and F$_1$ (Reimei ms ${\times}$ TP 681, Reimei ms ${\times}$ TP 1278) hybrid rices. Those of Indica type were 1378 (maintainer), Milyang 46 and Suweon 287(restorers), and F$_1$ (1378 ms ${\times}$ Milyang 46, 1378 ms ${\times}$ Suweon 287) hybrid rices. High heterosis in F$_1$ hybrid rices were shown in panicles per hill and spikelets per panicle, being greatest in spikelets per panicle. Spikelets per square meter expressed even greater heterosis than those two yield components because of multiplicative effect of them. Heterosisof ripened concentration of leaf nitrogen and steeper gradient of leaf nitrogen in canopy strata but also better productive structure in favor of light interception seemed to have led to higher canopy photosynthesis of F$_1$ hybrids and subsequent higher partition of assimilates for leaf area expantion especially during vegetative growth stage. Higher dry matter production, resulting from these factors, during vegetative stage would have contributed to the production of greater number of spikelets per square meter, and consequently to higher grain yield in F$_1$ hybrids.

• Journal of Korean Society of Forest Science
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• v.100 no.3
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• pp.359-366
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• 2011

The objective of this study was to analyze the changes of crown fire hazard possibility from the effects of forest tending works (FTW) in Pinus densiflora stands in Korea. The study sites were located in Youngju (FTW) and Bonghwa (Control) areas. Ten representative sample trees were destructively felled at each areas to analyze the crown fuel characteristics. The results of this study showed that crown fuel moisture content in Youngju and Bonghwa areas were 103.6% and 104.4%, respectively. The needles and twigs with less than 1cm diameter accounted 50.3% of the total crown fuel load in Youngju area and 62.0% in Bonghwa area. On the other hand, it was observed in Youngju that the canopy bulk density was $0.11kg/m^3$ lower but have 1.3 m higher average canopy base height therefore having a possibility of lower crown fire hazard as compared to Bonghwa that had higher canopy bulk density and lower canopy base height.

• Journal of Environmental Impact Assessment
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• v.17 no.5
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• pp.279-288
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• 2008

Vertical forest distribution is one of the important factors to understand various ecological mechanism such as succession, disturbance and environmental effects. LiDAR data provide information, both the horizontal and vertical distribution of forest structure. The laser scanner survey provided a point cloud, in which the x, y, and z coordinates of the points are known. The objectives of this study were 1) to analyze factors of forest structure such as individual tree isolation, tree height, canopy closure and tree density using LiDAR data and 2) to compare the forest structure between outer and interior forest. The paper conducted to extract the individual tree using watershed algorithm and to interpolate using the first return of LiDAR data for yielding digital surface model (DSM). The results of the study show characters of edge such as more isolated individual trees, higher density, lower canopy closure, and lower tree height than those of interior forest. LiDAR data is to be useful for analyzing of forest structure. Further study should be undertaken with species for more accurate results.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.12 no.1
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• pp.44-51
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• 2009

In order to determine air temperature difference by canopy layer in the forest, air temperatures were observed at Seolleung Park, Gahngnam-ku, Seoul. from November 9, 2007 to November 8, 2008 by 10 minute interval. The data were analyzed in terms of diurnal variation based on annual and monthly temperature difference. Using calm, less cloudy and no rainy weather data, average air temperature difference between forest and grass was observed as $0.8^{\circ}C$. The maximum air temperature difference was observed at 22:10, 23:20, 23:30 and 23:40 by $2.13^{\circ}C$ and the minimum one observed at 13:00 by $-0.84^{\circ}C$ in diurnal variation. The maximum temperature difference occurred at 19 : 50 on September by $3.67^{\circ}C$, Overall the air temperature in the forest was higher than that of grass at night and lower in midday.

• Journal of Ecology and Environment
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• v.45 no.2
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• pp.78-87
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• 2021

Background: To understand shade and wind effects on seedling traits of common reed (Phragmites australis), we conducted a mesocosm experiment manipulating day length (10 h daytime a day as open canopy conditions or 6 h daytime a day as partially closed canopy conditions) and wind speed (0 m/s as windless conditions or 4 m/s as windy conditions). Results: Most values of functional traits of leaf blades, culms, and biomass production of P. australis were higher under long day length. In particular, we found sole positive effects of long day length in several functional traits such as internode and leaf blade lengths and the values of above-ground dry weight (DW), rhizome DW, and total DW. Wind-induced effects on functional traits were different depending on functional traits. Wind contributed to relatively low values of chlorophyll contents, angles between leaf blades, mean culm height, and maximum culm height. In contrast, wind contributed to relatively high values of culm density and below-ground DW. Conclusions: Although wind appeared to inhibit the vertical growth of P. australis through physiological and morphological changes in leaf blades, it seemed that P. australis might compensate the inhibited vertical growth with increased horizontal growth such as more numerous culms, indicating a highly adaptive characteristic of P. australis in terms of phenotypic plasticity under windy environments.

• Korean Journal of Environment and Ecology
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• v.11 no.4
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• pp.493-505
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• 1998

To study vegetation structure and distance between trees of Pinus densiflora forest in Chayang-chon area, Soraksan National Park, thirty-nine plots(10m$\times$10m) were established. They were classified into two communities by TWINSPAN and DCA technique. In the Community I, P. densiflora(DBH 35~75cm, height 9~16m, age 60~80) dominated in canopy and were predicted to be changed by deciduous broad-leaved trees also. In the Community II, P. densiflora(DBH 9~26.5cm, height 9~16m, age 30~50m) dominated in canopy. It seemed that the community II would maintain P. densiflora community for a long time since P. densiflora dominated in both canopy and understory. Shonnon's diversity index was higher in the community II(1.4247) than in the community I(1.2978). The distantes between canopy trees were 4.92$\pm $2.14m in the community I and 2.41$\pm $0.97m in the community II. The regression between DBH in canpy and ecological distance was Y(Distance) = 0.06355$\times $(DBH)+1.51613.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.28 no.2
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• pp.272-279
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• 1983

Canopy structure and light interception were investigated as related to forage growth and dry matter production in four swards; pure orchardgrass, pure ladino clover, orchard-ladino mixture, and multi-mixture that was consisted of four grasses and three legumes. In spring, multi-mixture stand had the highest LAI, while ladino clover pure stand had low LAI but the highest leaf volume density(L$_{v}$ ). In fall, both pure orchardgrass and orchard-ladino mixture had higher LAI and L$_{v}$ than others. Orchard pure stand was an electophile canopy with K, light extinction coefficient, of 0.29-0.43, pure ladino clover a planophile canopy with K of 0.72, and both mixtures a plagiophile canopy with K of 0.43-0.58. Dry matter yields had highly significant correlation with LAI in all stands. Optimum LAI for pure orchardgrass was estimated above 6.0 and for pure ladino clover, orchard-ladino mixture and multi-mixture were about 3.8,5.0 and 8.0, respectively. Conclusion was made that multi-mixture and orchard-ladino mixture had better canopy structure to improve light penetration and forage yield than pure stands.

• Proceedings of the KSRS Conference
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• 2007.10a
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• pp.247-249
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• 2007

Crown parameters are important roles in tree species identification, because the canopy is the aggregate of all the crowns. However, crown measurements with spaceborne image data have remained more difficult than on aerial photographs since trees show more structural detail at higher resolutions. This recognized problem led to the initiation of the research to determine if high resolution satellite image data could be used to identify and classify single tree species. In this paper, shape parameters derived from pixel-based crown area measurements and texture features derived from GLCM parameters in QuickBird image were tested and compared for individual tree species identification. As expected, initial studies have shown that the crown parameters and the canopy texture parameters provided a differentiating method between coniferous trees and broad-leaved trees within the compartment(less than forest stand) for single extraction from spaceborne high resolution image.

• Journal of Plant Biology
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• v.14 no.3
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• pp.60-65
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• 1971

In order to observe the factors affecting light utilization efficiency in the canopy of a rice crop grown in reclaimed saline areas in Korea, 22 varieties of rice were cultured at the average salt concentration of 6.05mmhos/cm $25^{\circ}C$, (0.39%) in saline soils and non-saline silty loam soils. The inhibition of tillering ability by salt damage at the maximum tillering stage was greater than to growth in height. A significant direct correlation was observed between both ratios and salt concentration with each variety. In the salty areas the length of the flag leaf of the maturing stage showed a positive correlation with the production of rough rice while other living leaf showed a negative correlation. LAI of maturing stage was less in the salty area than in the non-salty area, while the former showed higher ratio in net assimilation and translocation to head with greater RGR before and after the heading stage.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.49 no.5
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• pp.394-406
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• 2004

A split-plot designed experiment including four rice varieties and 10 nitrogen levels was conducted in 2003 at the Experimental Farm of Seoul National University, Suwon, Korea. Before heading, hyperspectral canopy reflectance (300-1100nm with 1.55nm step) and nine crop variables such as shoot fresh weight (SFW), leaf area index, leaf dry weight, shoot dry weight, leaf N concentration, shoot N concentration, leaf N density, shoot N density and N nutrition index were measured at 54 and 72 days after transplanting. Grain yield, total number of spikelets, number of filled spikelets and 1000-grain weight were measured at harvest. 14,635 narrow-band NDVIs as combinations of reflectances at wavelength ${\lambda}l\;and\;{\lambda}2$ were correlated to the nine crop variables. One NDVI with the highest correlation coefficient with a given crop variable was selected as the NDVI of the best fit for this crop variable. As expected, models to predict crop variables before heading using the NDVI of the best fit had higher $r^2$ (>10\%)$ than those using common broad- band NDVI red or NDVI green. The models with the narrow-band NDVI of the best fit overcame broad- band NDVI saturation at high LAI values as frequently reported. Models using NDVIs of the best fit at booting showed higher predictive capacity for yield and yield component than models using crop variables.