• Atmosphere
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• v.27 no.4
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• pp.483-498
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• 2017

Sky view factor can quantify the influence of complex obstructions. This study aims to evaluate the best available SVF method that represents an urban thermal condition with land cover in complex city of Korea and also to quantify a correlation between SVF and mean air temperature; the results are as follows. First, three SVF methods comparison result shows that urban thermal study should consider forest canopy induced effects because the forest canopy test (on/off) on SVF reveals significant difference range (0.8, between maximum value and minimum value) in comparison with the range (0.1~0.3) of SVFs (Fisheye, SOLWEIG and 3DPC) difference. The significance is bigger as a forest cover proportion become larger. Second, R-square between SVF methods and urban local mean air temperature seems more reliable at night than a day. And as the value of SVF increased, it showed a positive slope in summer day and a negative slope in winter night. In the SVF calculation method, Fisheye SVF, which is the observed value, is close to the 3DPC SVF, but the grid-based SWG SVF is higher in correlation with the temperature. However, both urban climate monitoring and model/analysis study need more development because of the different between SVF and mean air temperature correlation results in the summer night period, which imply other major factors such as cooling air by the forest canopy, warming air by anthropogenic heat emitted from fuel oil combustion and so forth.

• Korean Journal of Agricultural Science
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• v.50 no.4
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• pp.663-673
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• 2023

The purpose of this study was to scientifically activate the forest healing program activities for the elderly. The predicted mean vote (PMV) and predicted percentage of dissatisfied (PPD), which are indices of thermal comfort in the thermal environment, and degree of canopy closure were compared and analyzed. Based on this information, the study objective was to present the appropriate conditions for maintaining the best comfort for the elderly. Six deck road shelters, which are the most active locations in forest healing programs among the National Center for Forest Therapy, were selected as the study sites. The results indicated that in the case of the conditions of 1 clo (clothing insulation value) and 1 met (metabolic rate) at an air temperature of 19 to 21 degrees in September on the measurement date, the PMV values ranged between -1.85 and -0.98 at all sites, and PPD values ranged between 25.60% and 68.68%. On the other hand, in the case of 1.3 clo and 1.6 met conditions, the PMV values ranged between -0.08 and 0.23 for all sites and PPD values ranged between 5.40 and 6.18. As shown above, the difference in thermal environment comfort and satisfaction according to the condition of the amount of metabolism and the amount of clothing could be confirmed. In addition, an analysis of the relation between PPD and canopy closure suggested a significantly positive correlation between them, and it was found that canopy closure was a factor affecting thermal comfort. Studies on effects of forest thermal environmental comfort and canopy closure on forest healing program areas should be conducted extensively according to seasonal conditions to provide information that can be used for more effective forest healing programs.

• Korean Journal of Soil Science and Fertilizer
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• v.5 no.1
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• pp.9-15
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• 1972

Comparative analyses of canopy structure were conducted using newly bred high yield rice cultivars (IR 667-Suwon 213 and 214) and commercial varieties (Jinhung and Paldal) under the field condition. "Canopy score" as criteria of canopy structure was proposed. The results were summerized as follows: 1. IR667 line (IR8${\times}$Taichung Native 1${\times}$Yukara) showed lower canopy height, greater tiller openness, smaller leaf openness and leaf length ratio (flag leaf/3rd), shorter 4th and 5th internode length, greater diameter of 5th internode, consequently greater leaf area index, panicle weight and leaf weight ratio (leaf/leaf sheathculm) as merits, and greater leaf width, smaller leaf number(number of leaf/$m^2$)and specific leaf area($cm^2/g$) and faster destruction of canopy by senescence as demerits comparing with commercial varieties. 2. IR 667 line showed much higher "Canopy score", subsequently higher yield. 3. The quality of individual leaf was better in the commercial varieties indicating that the best combination for the better yield would be the leaf of commercial varieties with the structure of IR667 line.

• Journal of Korean Society of Forest Science
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• v.107 no.4
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• pp.412-421
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• 2018

The objective of this study was to analyze the effects of forest management activities on canopy fuel characteristics for Pinus densiflora stands in South Korea. We used 1,085 managed stands data and 349 unmanaged stands data of the National Forest Inventory for this study, and it was estimated by using the Weibull function for the growth of stand and canopy fuel characteristics. Comparing the canopy fuel characteristics for the managed stands and unmanaged stands shows that the average canopy fuel load is about 14% higher than that of managed stands, and the canopy bulk density is also approximately 16% higher. The results of comparing growth projections for 40 years, 50 years and 60 years with the Weibull function are as follows: Over time, managed stands was predicted the maximum number of medium and large class diameter, while unmanaged stands was predicted maximum number of small and medium class diameter. From a fire fuel perspective, unmanaged stands are predicted to be of the type small class diameter and high density, which is a good condition for crown fire. In addition, Canopy fuel load, Canopy bulk density is relatively higher than managed stands, indicating that the possibility of high crown fire hazard.

• Atmosphere
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• v.25 no.3
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• pp.483-499
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• 2015

This study examined the impact of change of land-use and meteorological condition due to urbanization on heat environment in Seoul metropolitan area over a decade (2000 and 2009) using Weather Research and Forecasting (WRF)-Urban Canopy Model (UCM). The numerical simulations consist of three sets: meteorological conditions of (1) October 2000 with land-use data in 2000 (base simulation), (2) October 2009 with land-use data in 2000 (meteorological condition change effect) and (3) October 2009 with land-use data in 2009 (both the effects of land-use and meteorological condition change). According to the experiment results, the change of land-use and meteorological condition by urbanization over a decade showed different contribution to the change of heat environment in Seoul metropolitan area. There was about $1^{\circ}C$ increase in near-surface (2 m) temperature over all of the analyzed stations due to meteorological condition change. In stations where the land-use type changed into urban, large temperature increase at nighttime was observed by combined effects of meteorological condition and land-use changes (maximum $4.23^{\circ}C$). Urban heat island (UHI) over $3^{\circ}C$ (temperature difference between Seoul and Okcheon) increased 5.24% due to the meteorological condition change and 26.61% due to the land-use change. That is, land-use change turned out to be contributing to the strengthening of UHI more than the meteorological condition change. Moreover, the land-use change plays a major role in the increase of sensible heat flux and decrease of latent heat flux.

• Korean Journal of Environmental Biology
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• v.27 no.3
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• pp.266-271
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• 2009

This study was about three genus of Viola: V. rossii, V. japonica, and V. dissecta var. chaerophylloides which can live together under a deciduous forest canopy. The aim of the study was to directly compare reproductive characteristics of the three species under the same environmental condition. By taking a census of the morphologically different flowers, the results indicate that all three species opened chasmogamous flowers before the canopy of forest closed, but continuously opened cleistogamous flowers after the canopy closed. Numbers of seeds in a capsule followed an ascending order from V. rossii to V. japonica. Mass of seeds followed a descending order from V. rossii to V. japonica. Both results had statistical significance. In terms of characteristics of seed production, V. rossii has been adapted more than V. japonica, and V. dissecta var. chaerophylloides under the deciduous forest.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.805-809
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• 2008

Measurement of leaf area index (LAI) is useful for understanding rice growth, water use, and canopy light interception. The top nitrogen content(TNC) per unit area is an important quantitative index of the condition of nitrogen nutrition in rice production. The rapid and simple method of estimation of TNC, with the use of the existing nondestructive analyzing instruments chlorophyll meter SPAD-502 and plant canopy analyzer (PCA) LAI-2000, was scrutinized. Destructive measurement is time consuming and labor intensive. Our objective was to evaluate sampling procedures using the Li-Cor LI-1800, LAI 2000 plant canopy analyzer (PCA) for nondestructive estimation of rice LAI, and SPAD-502 on the Northern Plains of Cheongju. The LAI estimated by PCA tended to underestimate the LAI determined by actual measurement by about 20%. The estimation of LAI by PCA was judged to have a sufficient accuracy as a practical technique. A high positive correlation was obtained between the values of the SPAD reading and LAI. NDVI and LAI also showed a very high correlation. The values of the SPAD reading and LAI, and NDVI gave a high positive correlation. These results indicated that the method described in this study was effective as a simple and rapid method for the estimation of rice growth.

• Journal of Ecology and Environment
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• v.35 no.3
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• pp.235-242
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• 2012

Mikania micrantha, a neo-tropical vine, is spreading rapidly in the tropical part of Nepal and is now threatening the rural ecosystem including biodiversity and rural livelihoods. However, no attempt has been made to control the spread of M. micrantha. As a result, the vines are spreading freely and rapidly. After a thorough literature review and assessment of forest management practices, we proposed a manual cutting method, as it suits the Nepalese situation for several reasons: required labor is readily available, as local communities are managing forest patches, and the method does not have any potential adverse effects on non-target native species. Experimental plots were laid out in August 2011 to examine the effectiveness of manual cutting. Two different site types based on canopy coverage were selected and divided into three blocks based on cutting strategy. Four treatments were assigned across the experimental plots following a complete block design. We harvested above-ground biomass according to the assigned treatment. The results suggested that there should be at least two consecutive cuttings within a 3-week interval before flowering, and that three consecutive cuttings resulted in 91% mortality of the vines. In addition, cutting promoted regeneration of native plant species. Employing regular cutting operations can modify understory shade enhancing regeneration of native species, which is a desirable condition to constrain proliferation of M. micrantha. Periodic cuttings reduced the competitiveness of M. micrantha regardless of canopy openness, but native ground cover should be retained.

• Korean Journal of Remote Sensing
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• v.23 no.1
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• pp.21-32
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• 2007

Fire fuel map is one of the most critical factors for planning and managing the fire hazard and risk. However, fuel mapping is extremely difficult because fuel properties vary at spatial scales, change depending on the seasonal situations and are affected by the surrounding environment. Remote sensing has potential to reduce the uncertainty in mapping fuels and offers the best approach for improving our abilities. Especially, Hyperspectral sensor have a great potential for mapping vegetation properties because of their high spectral resolution. The objective of this paper is to evaluate the potential of mapping fuel properties using Hyperion hyperspectral remote sensing data acquired in April, 2002. Fuel properties are divided into four broad categories: 1) fuel moisture, 2) fuel green live biomass, 3) fuel condition and 4) fuel types. Fuel moisture and fuel green biomass were assessed using canopy moisture, derived from the expression of liquid water in the reflectance spectrum of plants. Fuel condition was assessed using endmember fractions from spectral mixture analysis (SMA). Fuel types were classified by fuel models based on the results of SMA. Although Hyperion imagery included a lot of sensor noise and poor performance in liquid water band, the overall results showed that Hyperion imagery have good potential for wildfire fuel mapping.

• 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.