• Journal of Korean Society of Forest Science
• /
• v.109 no.4
• /
• pp.468-476
• /
• 2020

we developed a stand density management diagram for Quercus variabilis in order to predict the final cutting ages of coppice forests based on management objectives. The sample data were classified into two groups: 603 data points for analysis and 113 data points for verification. Using these data, a stand density management diagram was constructed and a goodness-of-fit test was performed. The explanatory power (R2) of the constituent models for the stand density management diagram was 0.732 for the equivalent height curve and 0.990 for the equivalent diameter curve. According to the analysis of the final cutting age rangeof the highest production, the final cutting ages for 900 buds remaining per hectare was 42-44 years, and that for the 1,800 buds remaining per hectare was 38-42 years. With the third-grade log set as the production target, the final cutting age range with site index 16 and 14 was 25-28 years and 29-33 years, respectively. The results of this study provide baseline data for establishing a management plan for Q. variabilis coppice stands.

• Ecology and Resilient Infrastructure
• /
• v.9 no.2
• /
• pp.93-99
• /
• 2022

It was confirmed that the fish diversity decreased with increasing index of weir's density (IWD) in the four river systems. The IWD showed difference with watershed, it was high in the Nakdong River (NDR). Both two river systems of Gum River (GUR) and Yeongsan River (YSR) were similar, whereas relatively lower density observed in the Han River (HNR) system. A result of 2-Dimensional Kolmogorov-Smirnov (2-DKS) as a nonparametic test showed different threshold values affecting fish diversity with the river systems. The p-values based on D_max, were significantly different at 0.05 level (except for YSR). The threshold values affecting fish diversity were also different with watershed. The values were 1.6/km of the HNR, 1.3/km of the NDR, and 2.3/km of the GUR, respectively. The fish diversity was decreased when IWD is over threshold values. The IWD of total 404 rivers (about 33%) among 1,217 surveyed in this study showed above threshold value. These rivers should be considered first for evaluating river continuity. The IWD and threshold value suggested in this study would be useful for selecting a stream priority for river connectivity study.

• Ecology and Resilient Infrastructure
• /
• v.9 no.2
• /
• pp.100-106
• /
• 2022

The relationships between river length and weir density versus fish species observed were analyzed for 210 local rivers in the Seomjin River system (SJR). A nonlinear exponential relationship between river length and number of fish species were observed. Model coefficient was 0.03 and coefficient of determinant (R²) was 0.59, meaning that about 59.0% of total variance was explained by river length variable. Predicted value by model and observed number of species showed a difference. About 110 local rivers (about 52.4%) showed lower value than predictive value. The average index of weir's density (IWD) in the SJR was about 2.7/km, which was significantly higher than that of other river basins. As a result of nonparametric 2-Kimensional Kolmogorov-Smirnov (2-DKS) analysis based on the IWD, the threshold value affecting fish diversity was about 2.5/km (D_max=0.048, p<0.05). Above the threshold value, it means that the number of fish species would be decreased. In fact, the ratio of the expected species to the observed species was lowered to less than 70%, when the IWD is higher than the threshold value. To maintain aquatic ecological connectivity in future, it is necessary to manage IWD below the threshold value.

• Journal of the Korean Association of Geographic Information Studies
• /
• v.23 no.2
• /
• pp.21-35
• /
• 2020

Vegetation information is a very important factor used in various fields such as urban planning, landscaping, water resources, and the environment. Vegetation varies according to canopy density or chlorophyll content, but vegetation vitality is not considered when classifying vegetation areas in previous studies. In this study, in order to satisfy various applied studies, a study was conducted to set a threshold value of vegetation index considering vegetation vitality. First, an eBee fixed-wing drone was equipped with a multi-spectral camera to construct optical and near-infrared orthomosaic images. Then, GIS calculation was performed for each orthomosaic image to calculate the NDVI, GNDVI, SAVI, and MSAVI vegetation index. In addition, the vegetation position of the target site was investigated through VRS survey, and the accuracy of each vegetation index was evaluated using vegetation vitality. As a result, the scenario in which the vegetation vitality point was selected as the vegetation area was higher in the classification accuracy of the vegetation index than the scenario in which the vegetation vitality point was slightly insufficient. In addition, the Kappa coefficient for each vegetation index calculated by overlapping with each site survey point was used to select the best threshold value of vegetation index for classifying vegetation by scenario. Therefore, the evaluation of vegetation index accuracy considering the vegetation vitality suggested in this study is expected to provide useful information for decision-making support in various business fields such as city planning in the future.

• Korean Journal of Plant Resources
• /
• v.23 no.2
• /
• pp.172-178
• /
• 2010

This study was carried out to investigate abiotic and biotic environmental factors affecting homoharringtonine (HHT) contents of Cephalotaxus koreana, whereby, to provide basic information of high value-added industry production of HHT as a promising anti-cancer agent. For correlation between abiotic environmental factors (soil moisture, soil pH, habitat density and temperature) and HHT contents, the contents were highly correlated with soil moisture (0.77) and soil pH (-0.68). For multiple regression analysis of relationship between abiotic environmental factors (soil moisture and soil pH) and HHT contents, soil moisture appeared to be strongly affecting the contents relatively due to being significant at only its regression coefficient ($26.48^{***}$). For the effect of biotic environmental factors (damage index) affecting HHT contents, the contents was quadratic with equation of $H=278.23+1242D-398.87D^2$, also, damage index had strong effect on the contents. Finally, for the result of the most influencing an environmental factor on HHT contents, both damage index and soil moisture were suitable in second polynomial regression, also, damage index ($R^2=0.73^{***}$) was turned out to be more influencing factor than soil moisture ($R^2=0.67^{**}$) on HHT contents relatively. Therefore, we predict that HHT contents in the trees of Cephalotaxus koreana is produced as a chemical defense mechanism triggered by a stress-related damage of fungi or insects.

• Applied Chemistry for Engineering
• /
• v.33 no.4
• /
• pp.373-380
• /
• 2022

In this study, Chung's equations 1, 2, and 3 were extended to standardize smoke safety rating evaluation in case of fire, and Chung's equations-V, smoke performance index-V, and smoke growth index-V were calculated. Five types of wood were selected and their smoke indices were measured using the cone calorimeter method according to ISO 5660-1. The smoke risk was graded by the smoke risk index-VI according to Chung's equation-VI. Smoke risk index-VI increased in the order of PMMA (1) ≈ maple (1.01) < ash (1.57) < needle fir (4.98) < paulownia (46.15) < western red cedar (106.26). It was predicted that maple and ash had the lowest smoke risk, and paulownia and western red cedar had the highest. The five samples' CO mean production rate (COP_mean) was 0.0009~0.0024 g/s, indicating that these woods were incompletely burned than the polymethyl methacrylate (PMMA) reference material. Regarding the smoke properties of the chosen woods, the smoke performance index-V (SPI-V) increased as the bulk density increased, and the smoke risk index-VI (SRI-VI) decreased.

• Journal of Environmental Impact Assessment
• /
• v.26 no.5
• /
• pp.315-330
• /
• 2017

The aim of this study is to examine the damage of plants in the islands due to the habitat and feeding of European rabbit (Oryctolagus cuniculus) and to suggest future management plan. The survey area Beomseom Island is found to be a vegetation distribution type that was formed secondary by the exposure of artificial interference except for evergreen vegetation distribution and European rabbit showed high habitat track density mainly in the lumbering area. Kkamakseom Island was identified as a severe vegetation distribution area due to interference, and European rabbit showed high habitat track density around deciduous broad leaved forests. Feeding plants of European rabbit was identified as a total of 12 families 17 breeds. Total 9 families 11 breeds were found in Beomseom Island while 5 families 6 breeds were found in Kkamakseom where most available food resources were loss to European rabbit. As for vegetation index of Beomseom Island, about 6.6% of total island area was declined and the vegetation index of Kkamakseom Island was reduced at most area of the island. In Kkamakseom Island, the area where EVI decreased to less than -0.008 unit/yr was reduced to 5.2%, and the area where it was reduced to -0.008 to -0.006 unit/yr in total was 13.32% of the total area. Thus, it was estimated to be seriously damaged by vegetation. Therefore, immediate management is required.

• Korean Journal of Food Science and Technology
• /
• v.39 no.2
• /
• pp.146-151
• /
• 2007

Resistant starch (RS) content, paste viscosity, water solubility and absorption index, bulk density, color, compression force, and bowl life of Goami flakes manufactured by extrusion process were determined to evaluate Goami (high fiber rice) as a food material. Various extrusion process conditions included barrel temperature (90, 110, $130^{\circ}C$) and moisture content (50, 55%). RS content in the extruded pellet and defatted flake ranged from $8.00{\sim}8.56%$ and $6.57{\sim}9.53%$ respectively. RS content increased as moisture increased from 50% to 55%. Peak viscosity, trough viscosity, final viscosity, and setback viscosity of the extruded pellet and defatted flake decreased with steeping for 1 hr, and the breakdown viscosity significantly increased. The water solubility and absorption index increased in the flake compared to Goami and extruded pellet. The water solubility index of the extruded pellet was lower than that of Goami, while its water absorption index was higher than Goami. The bulk density of the flake ranged from $0.35{\sim}0.44$ g/mL. The bowl life of the flake was $12.4{\sim}19.4$ min, which was longer than commercial breakfast cereals on the market.

• Korean Journal of Soil Science and Fertilizer
• /
• v.34 no.4
• /
• pp.237-244
• /
• 2001

Investigation on the surface charge properties of some Korean arable soils was performed by ion adsorption technique with two kinds of indifferent ion ($Na^+$ and $K^+$) at the range of pH 3 to 9 in bulk solution. The contribution of soil components(organic matter, oxides and clay mineral) on the surface charge density was determined at two soil depth with different solid particle composition When the pH of solution increased, the negative charge of soil surface was increased among the all soils, but positive charge were not appeared above pH 6. apparently. The magnitude of surface charge density measured by NaCl adsorption method showed ra nges of $0.01{\sim}2.84cmol_c{\cdot}kg^{-1}$ and $7.41{\sim}12.20cmol_c{\cdot}kg^{-1}$ at pH 3 and pH 9, respectively. Ion adsorption method using KCl as index ion overestimated than the method using NaCl as index ion. The content of organic matter is the strongest factor on the value of dCEC/dpH.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.35 no.5
• /
• pp.62-71
• /
• 2003

This study was carried out to develop the bio-chemical pulping method to enhance the energy saving and decrease the capital cost through the soda pulping under atmospheric pressure ($100^{\circ}C$). Nonwood substrates, rice straw, were pretreated by white-rot fungi, Pleurotus cornucopiae. Several basic pieces of data that can be applied in soda pulping were acquired. The results of this study were as follows. Under the conditions without any nutrients or with glucose, N and glucose + N, the weight losses of rice straws inoculated by Pleurotus cornucopiae were 12.1∼32.6 %, 12.0∼26.3 %, 13.0∼25.4 % and 15.3∼24.7 % for 5, 10, 15, 20, 25 and 30 days incubation periods respectively. The more the fungal incubation was extended, the more the weight losses were gained. The yield of untreated rice straw was 54.8 % after pulping. When any nutrients was not added or glucose, N and glucose ＋ N were added for the pretreatment, the total yields were ranged to 57.3∼42.9 %, 51.0∼43.3 %, 51.7∼43.9 % and 52.1∼46.1 % for 5 different incubation periods respectively. The yields were gradually decreased based on the extending of the incubation periods. The physical properties of the rice straw soda pulp without fungal treatment, the density, breaking length, burst index, tear index and folding endurance were 0.24g/㎤, 2.32 Km, 0.91 kPaㆍ$m^2$/g, 46.7 mNㆍ$m^2$/g and 21 times, respectively. In the case of pretreatment without any nutrients or with glucose, N and glucose + N as nutrients, the density was 0.24g/㎤, the breaking length was 3.30∼6.46 Km, the burst index was 1.36∼3.01 kPaㆍ$m^2$/g, the tear index was 33.0∼57.0 mNㆍ$m^2$/g and the folding endurance was 14∼381 times at most incubating periods, when pulping was done. The physical properties were increased as the incubation duration was extended. Especially, when N and glucose ＋ N were added, the physical properties showed superior results during each incubation period.