• Journal of the Korean Wood Science and Technology
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• v.42 no.6
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• pp.653-658
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• 2014

This research was carried out to investigate equilibrium moisture content (EMC) of wood in outdoor locations in Korea. EMC was calculated using Hailwood-Horrobin equation for 73 different locations in Korea using the 1981 to 2010 climate normal data obtained from the Korea Meteorological Admnistration (KMA). Daegu showed the lowest values of EMC (11.5), and the highest EMC values (15.8) was found in Heuksando. Considering the season effect, summer (June, July, August) showed the highest values 15.3, followed by autumn (September, October, November) 13.7, winter (December, January, February) 12.2, and spring (February, March, April) 12.0. Monthly EMC showed the lowest values 11.6 in April and July showed the highest EMC values 16.1. The smallest changes in monthly EMC were found in Jeju island and Heuksando showed the largest values 8.7. A proper wood drying based on average EMC is more required in the regions with larger variation in EMC.

• Journal of the Korean Wood Science and Technology
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• v.10 no.2
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• pp.3-11
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• 1982

In order to investigate the annual mean equilibrium moisture content(EMC), the equilibrium moisture content investigated were the desorbed and adsorbed equilibrium moisture content with two end-matched samples for red pine (Pinus densiflora S. et Z.), Douglas fir (Pseadotsuga menziesii Franco), oak (Quercus mongolica Fischer) and red lauan (Shorea spp.) in instrument screen at forest experiment station located in Seoul, Chuncheon, Daejeon, Kyungju, Jinju and Gwangju area for four years (1970. 1 - 1973. 12). The results summarized were as follows. 1. The annual mean desorbed equilibrium moisture content of red pine, Douglar fir, oak and red lauan were 14.8, 13.7, 14.0 and 14.2 percent respectively and higher than the annual mean adsorbed equilibrium moisture content of those species. 2. The annual mean desorbed - and adsorbed equilibrium moisture content in central areas (Seoul, Chuncheon, Daejeon) were higher than those in southern areas (Kyungju, Jinju, Gwangju). 3. On the whole, the monthly mean desorbed - and adsorbed equilibrium moisture content were lowest in April and highest in August though difference of month in areas. 4. Average and range of annual national equilibrium moisture content was 12.3 ~ 14.2 ~ 15.7 percent for desorbed equilibrium moisture content and 11.3 ~ 13.2 ~ 14.7 percent for adsorbed equilibrium moisture content and 12.0 ~ 14.1 ~ 16.4 percent for calculated equilibrium moisture content based on tempera ture and humidity.

• Journal of the Korean Wood Science and Technology
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• v.10 no.3
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• pp.109-117
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• 1982

In order to investigate the annual mean equilibrium moisture content (EMC), the equilibrium moisture content investigated were the desorbed - and adsorbed equilibrium moisture content with two end-matched samples for red pine (Pinus densiflora S. et Z.), Douglas fir (Pseadotsuga menziesii Franco), oak (Quercus mongolica Fischer) and red lauan (Shorea spp.) in instrument screen at forest experiment station located in Seoul, Chuncheon, Daejeon, Kyungju, Jinju and Gwangju area for four years (1970. 1 - 1973. 12). The results summarized were as follows. 1. The annual mean desorbed equilibrium moisture content of red pine, Douglar fir, oak and red lauan were 14.8, 13.7, 14.0 and 14.2 percent respectively and higher than the annual mean adsorbed equilibrium moisture content of those species. 2. The annual mean desorbed - and adsorbed equilibrium moisture content in central areas (Seoul, Chuncheon, Daejeon) were higher than those in southern areas (Kyungju, Jinju, Gwangju). 3. On the whole, the monthly mean desorbed - and adsorbed equilibrium moisture content were lowest in April and highest in August though difference of month in areas. 4. Average and range of annual national equilibrium moisture content was 12.3 ~ 14.2 ~ 15.7 percent for desorbed equilibrium moisture content and 11.3 ~ 13.2 ~ 14.7 percent for adsorbed equilibrium moisture content and 12.0 ~ 14.1 ~ 16.4 percent for calculated equilibrium moisture content based on tempera.

• Journal of Korean Society of Forest Science
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• v.83 no.4
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• pp.540-544
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• 1994

Equilibrium moisture contents(EMC) were calculated based on temperature and relative humidity of atmosphere and actual EMCs were measured at intervals of ten days in previous air-dried wood samples for seven different species including Douglas fir and oaks in four indoor locations in central region for one year. Mean annual air temperature and relative humidity were $23.3^{\circ}C$ and 54.9% in bedroom, $22.4^{\circ}C$ and 59.5% in living room of apartment, $20.1^{\circ}C$ and 57.0% in office room and 19.4 and 64.0% in living room of tile-roofed house, respectively. Mean annual calculated and actual EMCs were 10.2 and 9.7% in bedroom, 11.1 and 10.2% in living room of apartment, 10.7 and 10.4% in office room, and 12.1 and 12.5% in living room of tile-roofed, house, respectively. Actual EMC of kasai were higher than average value of EMC for seven species. However, those of sycamore and apitong were lower than average value.

• Journal of the Korean Association of Geographic Information Studies
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• v.22 no.3
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• pp.21-36
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• 2019

Dead fuel moisture content is a key variable in fire danger rating as it affects fire ignition and behavior. This study evaluates simple regression models estimating the moisture content of standardized 10-h fuel stick (10-h FMC) at three sites with different characteristics(urban and outside/inside the forest). Equilibrium moisture content (EMC) was used as an independent variable, and in-situ measured 10-h FMC was used as a dependent variable and validation data. 10-h FMC spatial distribution maps were created for dates with the most frequent fire occurrence during 2013-2018. Also, 10-h FMC values of the dates were analyzed to investigate under which 10-h FMC condition forest fire is likely to occur. As the results, fitted equations could explain considerable part of the variance in 10-h FMC (62~78%). Compared to the validation data, the models performed well with R2 ranged from 0.53 to 0.68, root mean squared error (RMSE) ranged from 2.52% to 3.43%, and bias ranged from -0.41% to 1.10%. When the 10-h FMC model fitted for one site was applied to the other sites, $R^2$ was maintained as the same while RMSE and bias increased up to 5.13% and 3.68%, respectively. The major deficiency of the 10-h FMC model was that it poorly caught the difference in the drying process after rainfall between 10-h FMC and EMC. From the analysis of 10-h FMC during the dates fire occurred, more than 70% of the fires occurred under a 10-h FMC condition of less than 10.5%. Overall, the present study suggested a simple model estimating 10-h FMC with acceptable performance. Applying the 10-h FMC model to the automatic mountain weather observation system was successfully tested to produce a national-scale 10-h FMC spatial distribution map. This data will be fundamental information for forest fire research, and will support the policy maker.

• Journal of Korean Society of Forest Science
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• v.54 no.1
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• pp.36-40
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• 1981

with the chemical equilibrium formula by Hailwood and Horrobin, $$m=a{\cdot}((k_1k_2h)(1+k_1k_2h)^{-1}+(k_2h)_n-k_2h)^{-1})$$, based on absorption theory, monthly equilibrium moisture content(EMC) variations in southern Korea were predicted. The results were as follows: $$k_1=47370272{\cdot}10^{-7}+477345{\cdot}10^{-7}t-502775{\cdot}10^{-8}t^2$$ $$k_2=705940864{\cdot}10^{-9}+16979472{\cdot}10^{-10}t-555336{\cdot}10^{-11}t^2$$ $$w=2233848{\cdot}10^{-4}+694242{\cdot}10^{-6}+185328{\cdot}10^{-7}t^2$$ Here, it is temperature degrees in Celsius, k is the equilibria between hydrate water and dissolved water, k is the equilibria between dissolved water and the water vapour pressure surrounding atmosphere, w is the molecular weight of the polymer unit that forms the hydrate, h is the relative vapour pressure, And the formula was well agreed with the data when the constant values ${\alpha}$ were given to be 2200 in January, February, October, November and December, 1850 in March, April and May, 1920 June, July, August, and September seasonally.