• Journal of Environmental Science International
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• v.20 no.7
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• pp.839-843
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• 2011

We have established a wind map of Singapore, a city-state characterized its land cover by urban buildings to confirm a possibility of wind farm development. As a simple but useful approximation of urban canopy, a zero-plane displacement concept was employed. The territory is divided into 15 sectors having similar urban building layouts, and zero-plane displacement, equivalent roughness height at each sector was calculated to setup a terrain boundary condition. Annual mean wind speed and mean wind power density map were drawn by a CFD micrositing model, WindSim where Changi International Airport wind data was used as an in-situ measurement. Unfortunately, predicted wind power density does not exceed 80 $W/m^2$ at 50 m above ground level which would not sufficient for wind power generation. However, the established Singapore wind map is expected to be applied for wind environment assessment and urban planning purpose.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.50 no.5
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• pp.332-335
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• 2005

The three Korean wheat cultivars with different plant types; the erect, the middle and the creeping growth habit, were studied for their utilization to solar radiation, temperature changes on the furrow and to provide optimum planting space for producing the high yield in 2003. The average solar radiation rate was lowest for creeping type ($39.2\%$) and highest for erect type ($75.8\%$) The correlation coefficient between the coverage rate and the solar transmission rate was r = 0.8624 which was significant at $5\%$ level. The relative growth of the plant, tiller rate and leaf size was increased in the erect and the middle type at lower plant density, while no change on plant growth at creeping type regardless of plant density. The increase of leaf size in the lower plant density was due to longer flag and the first leaf than those of other plant types. The temperature on the furrow of growing plants was changed by the canopy. The changes in temperature pattern on the furrow according to plant types during winter season was different compared to the non plant ground. The temperature of the nonplant ground was the lowest due to solar reduction increasing the amount of cool air flowing in the furrow.

• Journal of Korean Society of Forest Science
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• v.96 no.2
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• pp.227-234
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• 2007

The forest canopy gap has been well known as a substantial process of forest cyclic regeneration and important role in stand structure, dynamics, and biodiversity of the forest ecosystem. Based on 3,600 $5m{\times}5m$ square grids in a 9ha permanent experimental plot, the study was conducted to evaluate the regeneration pattern of woody species by developmental stage {seedlings (<1 m of height), saplingI (>1 m of height, <2 cm of DBH), and saplingII (2 cm$<200m^2$), $201-400m^2$, $400-600m^2$, $601-800m^2$, and $>800m^2$) in the mixed broadleaved-Korean pine forest. The results indicated that the regenerating trees of Populus ussuriensis occurred only in the canopy gap area, considered to be a typical gap-dependent species. The regeneration of Ulmus japonica, Ulmus laciniata, and Maackia amurensis could be generally satisfied with the gap size of $201-600m^2$, Betula costata and Prunus padus with gap size of $401-800m^2$, Picea koraiensis with gap size of $201-800m^2$, Fraxinus mandshurica and Syringa reticulata var. mandshurica with smaller than $800m^2$, respectively. Acer ukurunduense and Acer tegmentosum were likely to have no problem with the gap size to make gap regeneration. Acer mono and Tilia amurensis looked more capable of regenerating in the closed canopy disregarding the upper crown condition. The regeneration of Pinus koraiensis and Abies nephrolepis had no trouble under the canopy condition in less than $800m^2$of gap size. The density of regenerating shrubs was rather high, especially under the closed canopy, considered to be associated with great amount of regeneration production in such shade tolerant species as Lonicera maackii, Corylus mandshurica, Euonymus pauciflorus, and Philadelphus schrenkii under the closed canopy. Pearson correlation coefficient was computed to compare the similarity among non-gap area and five gap size classes by developmental stages for trees and shrubs. The similarity coefficients among closed canopy and the gap size classes were mostly significantly correlated to each other with a few exceptions.

• Korean journal of applied entomology
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• v.42 no.3
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• pp.233-240
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• 2003

The effect of density suppression of Amblyseius fallacis (Garman) against Panonychus citri (McGregor) on citrus tree introduced with some different ratio was investigated. When it was introduced with over 16:1 (Panonychus citri: A. fallacis) ratio, Panonychus citri was suppressed very effectively. And in case of introduced once or two times with 20: 1 ratio when the density of Panonychus citri was reached 0.5 and 1.0 per leaf, the density of A. fallacis was formed highly, but the suppression effect against Panonychus citri was not effective. Also, the density changes of P. citri and A. fallacis on the citrus tree released with 10: 1 ratio (P. citri: A. fallacis) when the density of P. citri was reached about 0.1 per leaf in plastic film house were investigated. In case of released twice at the interval of 10 days, the density of A. fallacis was high and P. citri was suppressed so effectively over two month. On the inside of canopy of the citrus tree planted in plastic film house, the air temperature was much lower than on the outside of canopy, while relative humidity was much higher.

• The Korean Journal of Ecology
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• v.10 no.2
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• pp.63-80
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• 1987

Detrended correspondence analysis(DCA) and two way indicator species analysis(TWINSPAN) were applied to Pinus densiflora stands nearby Seoul area in order to classify them into several groups based on herbaceous species and environmental relationships. The eighteen Pinus densiflora stands were perferenially selected, In each stand, 30 to 60 quadrats, (20X20)cm, were randomly estabilished. In each quadrat, all stems for herbaceous plants were recorded by species and their covers were measured. In addition environmental factors such as soil depth, thickness of litter layer, soil compressibility, tree density, basal area, elevation, slope and exposure were detemined for each stand. Four to twelve soil cores were collected and physical and KDICical properties were determined. This survey was conducted form 15, July, 1985 to 22, September, 1985. Analysis of the vegetation and environmental data were performed with DECORANA and TWINSPAN. Stand ordination (DECORANA) and classification (TWINSPAN) based on herbaceous species suggest that the stands can be classified into five groups in terms of herbaceous species composition and environmental relationships. Type I, Type II, Type III, Type IV and Type V were classified to SUBMESIC-CLO-SED-CANOPY (Artemisia keiskeana, Carex nanella), MESIC-CLOSED CANOPY (Spodiopogon sibiricus, Miscanthus sinensis, Carex nanella, Pteridum aquilinum, Melampyrum rosium), SUBMESIC-OPEN CANOPY (Carex nanella, Spodiopogon sibiricus, Miscanthus sinensis), XERIC-CLOSED CANOPY (Carex nanella, Spodiopogon sibiricus, Carex nanella), and XERIC-OPEN CANOPY (Arundinella hirts, Spodiopogon sibiricus, Carex nanella), respectively. These results were consitent with environmental trends on stan ordination. Application of the ordination and classifiaction to Pinus densiflora stands were effective as a approach on obtaining perliminary ecological information.

• Journal of Korean Society for Geospatial Information Science
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• v.20 no.1
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• pp.83-91
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• 2012

Crown density, which is defined as the proportion of the forest floor concealed by tree crown, is important and useful information in various fields. Previous methods of measuring crown density have estimated crown density by interpreting aerial photographs or through a ground survey. These are time-consuming, labor-intensive, expensive and inconsistent approaches, as they involve a great deal of subjectivity and rely on the experience of the interpreter. In this study, the crown density of a forest in Korea was estimated using KOMPSAT-2 high-resolution satellite images. Using the image segmentation technique and stand information of the digital forest map, the forest area was divided into zones. The crown density for each segment was determined using the discriminant analysis method and the forest ratio method. The results showed that the accuracy of the discriminant analysis method was about 60%, while the accuracy of the forest ratio method was about 85%. The probability of extraction of candidate to update was verified by comparing the result with the digital forest map.

• Korean Journal of Ecology and Environment
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• v.43 no.1
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• pp.91-102
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• 2010

Water quality and epiphytic diatom on the submerged stems of reed (Phragmites communis), which occupy 90% of the Donghwa wetland macrophytes were monthly monitored at three points such as inflow stream, high- and low-level wetlands, and outflow stream between March and October, 2005. 1) A diverse and high density of diatom species observed in the cold-season, especially Nitzschia palea and Nitzschia amphibia dominated the diatom community without wetlands. 2) High DAIpo and TDI indices were measured over the sampling periods and stations, regardless of nitrogen increase and phosphorus increase through the wetlands. 3) Higher density of diatom species in high wetland than low wetlands was attributed in the enough nutrients and light penetration by low growth of reed. Therefore, epiphytic diatom of reed stem in Donghwa wetland, where high nutrients released from the sediment and reed debris after the death of macrophytes, flourished with low canopy of low reed vegetation.

• The Plant Pathology Journal
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• v.32 no.6
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• pp.508-518
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• 2016

Early blight of tomato caused by Alternaria solani, is responsible for severe yield losses in tomato. The conidia survive on soil surface and old dry lower leaves of the plant and spread when suitable climatic conditions are available. Macroclimatic study reveals that highest inoculum concentration of Alternaria spores appeared in May 2012 to 2013 and lowest concentration during January 2012 to 2013. High night temperature positively correlated and significantly (P < 0.01) involved in conidial spore dispersal and low relative humidity (RH) displayed significant (P < 0.05) but negative correlation with conidial dispersal. The objective of the study was to modify microclimatic conditions of tomato crop canopy which may hamper conidial dispersal and reduce disease severity. We evaluated effect of marigold intercropping and plastic mulching singly and in consortia on A. solani conidial density, tomato leaf damage and microclimatic parameters as compar to tomato alone (T). Tomato-marigold intercropping-plastic mulching treatment (T + M + P) showed 35-39% reduction in disease intensity as compared to tomato alone. When intercropped with tomato, marigold served as barrier to conidial movement and plastic mulching prevented evapotranspiration and reduced the canopy RH that resulted in less germination of A. solani spores. Marigold intercropping and plastic mulching served successfully as physical barrier against conidial dissemination to diminish significantly the tomato foliar damage produced by A. solani.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.328-330
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• 2003

The land cover of burned area has changed dramatically since Daxinganling forest fire in Northeastern China during May 6 ? June 4, 1987. This research focused on determining the burn severity and assessment of forest recovery. Burned severity was classified into three levels from June 1987 Landsat TM data acquired just after the fire. A regression model was established between the forest canopy closure from 1999 forest stand map and the NDVI values from June 2000 Landsat ETM+ data. The map of canopy closure was got according to the regression model. And vegetation cover was classified into four types according to forest closure density. The change matrix was built using the classified map of burn severity and vegetation recovery. Then the change conversions of every forest type were analyzed. Results from this research indicate: forest recovery status is well in most of burned scars; and vegetation change detection can be accomplished using postclassification comparison method.

• 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.