• Proceedings of the KSRS Conference
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• v.1
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• pp.102-105
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• 2006

Forest canopy density is an essentially important for maintaining the diversify flora and fauna in the tropic. But, the natural and human disturbances have an influence over the inconsistency of forest canopy density. So, forest canopy density (FCD) has been threatened in the tropic since a decade. The objective of this study was to examine the dynamics change of the forest canopy density in tropical forest Chitwan, Nepal combine with field survey and remote sensing data. The field survey data of 2001 such as canopy cover percentage, dbh so on and some human disturbances were used. Similarly, Landsat TM 1988 and ETM+ 2001 have also used to predict the dynamic changes of the FCD over the period. Moreover, nonparametric Kruskal- Wallis test has performed for the validation of the results. Data analysis revealed that very few factors i.e. the number of trees, path, and fire had realized statistically significance at P=<0.05. Therefore we concluded that detail analysis could be needed incorporate with additional socioeconomic, climatic, biophysical and institutional factors for the better understanding of the forest canopy dynamic in particular location.

• Proceedings of the Korean Society of Environment and Ecology Conference
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• 2003.10a
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• pp.155-157
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• 2003

• Korean journal of applied entomology
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• v.49 no.2
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• pp.159-162
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• 2010

Diprion hani Smith and Cho was first reported as a new species from South Korea in 2007. Major outbreaks occurred in September 2007. Outbreaks were restricted geographically to only three inland areas of central Korea where had previously been reforested with Korean white pine, Pinus koraiensis Seib. & Zucc. The outbreak areas were approximately 50 km in diameter. The sawfly populations decreased drastically in 2008. Environmental factors of the outbreak sites were investigated as a first step to characterize the sites and to understand the population dynamics of the sawfly. During the outbreak in 2007, the average temperature of the sites were $1.3^{\circ}C$ higher than the 30 years average, and the annual precipitation was 384 mm higher than the average from 1971 to 2000. In addition, Monodontomerus dentipes (Dalman), a well-known torymid parasitoid of many sawflies, is reported as a gregarious cocoon parasitoid of D. hani.

• Journal of Korean Society of Forest Science
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• v.87 no.1
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• pp.106-112
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• 1998

This study was conducted to figure out the relationships among soil chemical properties and bacterial biomass related to denitrification and sulfur-reducing and the activity of dehydrogenase, and ultimately to consider the usefulness of dehydrogenase activity as a tool for evaluating the dynamics of forest soil ecosystem. Four sites were selected for the collection of soil samples within two regions(Onsan industrial estate as a polluted region and Mt. Mani at Kanghwa island as a clean area) with two forest types (coniferous and deciduous stands). The soils of Mt. Mani showed higher amount of organic matter, total nitrogen and available phosphorus than those collected from Onsan industrial estate, which indicated that the soils were more beneficial for microbial growth than those of Onsan. The dehydrogenase activity was more sensitive than the denitrifying bacteria or sulfur-reducing bacteria since the activity was significantly different between the regions and season while the two bacterial biomass were not significantly different between the two regions. In addition, the dehydrogenase activity showed relatively high correlation coefficients with organic matter(r=0.53, p=0.004), total nitrogen(r=0.41, p=0.008) and C/Ava. P-ratio(r=-0.52, p=0.001), which was thought to be closely related with microbial activity. Thus, the dehydrogenase activity was thought to be a useful index of soil ecosystem dynamics with considering that the technique need to be applied with the same soil texture for the comparison of the activity as other researchers indicated.

• Journal of Korean Society of Forest Science
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• v.87 no.4
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• pp.528-534
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• 1998

There are many parameters in prediction of forest fire spread. Among others wind and slope factors are considered to be the important parameters in spread of forest fire. Generally, all the inclined planes with same slopes can not have the same wind velocity in complex mountain area. But this effect has been disregarded in complex geometry. In this paper, wind values which have velocity and direction is calculated by applying computational fluid dynamics to the forest geometry. These results are applied for forest fire spreading algorithm with experimental Korean ROS(Rate Of Spread). Finally, the comparison between the simulation and the real forest fire has correspondence about 90%.

• Journal of Forest and Environmental Science
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• v.34 no.6
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• pp.472-480
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• 2018

This study was conducted to estimate carbon storage in Quercus mongolica stands based on stand age class, and to provide basic data on the carbon balance of broad-leaved forests of Korea. The research was conducted at the experimental forest of Kangwon National University, Hongcheon-gun County, Gangwon-do Province, Korea. Three plots were set up in each of three Q. mongolica forest stands (III, V, and VII) to estimate the amount of carbon stored in Q. mongolica aboveground vegetation, coarse woody debris (CWD), organic layer, mineral soil, and litterfall. The carbon storage of the aboveground vegetation increased with an increase in stand age, while the carbon storage ratio of stems decreased. The carbon storage of the organic layer, CWD, and litterfall did not show any significant differences among age classes. In addition, the carbon concentration and storage in the forest soils decreased with depth, and there were no differences among age classes for any soil horizon. Finally, the total carbon storage in the III, V, and VII stands of Q. mongolica were 132.2, 241.1, and $374.4Mg\;C\;ha^{-1}$, respectively. In order to predict and effectively manage forest carbon dynamics in Korea, further study on deciduous forests with other tree species in different regions will be needed.

• Journal of Korean Society of Forest Science
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• v.90 no.2
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• pp.217-226
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• 2001

This study estimated the impacts of the building permit area change on the forest products import quantities in Korea. The first objective of this dissertation is to analyze whether there is any causal relationship between change in the building permit area and changes in the import quantities of forest products in Korea. Assuming that there is any causal relationship, the second objective is to evaluate the dynamics of the impacts of the building permit area change on the forest products import quantities in Korea. The relationship between the building permit area and the import quantity was represented by bivariate vector autoregressive or vector error correction model. Whether there is any causal relationship between change in the building permit area and changes in the import quantities of forest products was analyzed by the causality test of Granger. And the dynamics of the impacts of the building permit area change on the forest products import quantities were evaluated by variance decomposition analysis and impulse response analysis. The import quantity of forest products can be explained by the lagged building permit area variables and the lagged import quantity variables in Korea. Change in the building permit area causes change in the high-density fiberboard import quantity in Korea. In the bivariate model of the high-density fiberboard import quantity, after six months, the building permit area change accounts for about ten percent of variation in the import quantity, and its own change accounts for about ninety percent of variation in the import quantity. On the other hand, the impact of a shock to the building permit area is significant for about six months on the import quantity of high-density fiberboard in Korea. That is, if the building permit area change indeed had an impact on the import quantity of high-density fiberboard in Korea, it was only of a short-term nature.

• Korean Journal of Agricultural and Forest Meteorology
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• v.5 no.2
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• pp.87-93
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• 2003

Litterfall and litter decomposition represent a major contribution to the carbon and nutrient inputs in a forest ecosystem. We measured litterfall quantity and nutrient dynamics in decomposing litter for two years at the Kwangneung broadleaf natural forest (DK site) in Korea. Litterfall was collected in circular littertraps (collecting area : 0.25 $m^2$) and mass loss rates and nutrient release patterns in decomposing litter were estimated using the litterbag technique employing 30 cm ${\times}$ 30 cm nylon bags with 1.5 mm mesh size. Total annual litterfall was 5,627 kg/ha/yr and leaf litter accounted for 61 % of the litterfall. The leaf litter quantity was highest in Quercus serrata, fallowed by Carpinus laxiflora and C. cordata, etc., which are dominant tree species in the site. Mass loss from decomposing leaf litter was more rapid in C. laxiflora and C. cordata than in Q. serrata litter. About 77% of C. laxiflora and 84% of C. cordata litter disappeared, while about 48% in Q. serrata litter lost over two years. Lower mass loss rates of Q. serrata litter may be attributed to the difference of substrate quality such as lower nutrient concentrations compared with the other litter types. Nutrient concentrations (N, P, Mg) of three litter types except for potassium (K) increased compared with initial nutrient concentrations of litter over the study period. Compared with Q. serrata litter, nutrients (N, P, K, Ca, Mg) in C. laxiflora and C. cordata litter were released rapidly. The results suggest that litter mass loss and nutrient dynamic processes among tree species vary considerably in the same site conditions.

• Journal of Korean Society of Forest Science
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• v.90 no.5
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• pp.663-671
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• 2001

This study estimated the impacts of the interest rate change on the forest products import quantities in Korea. The first objective is to analyze whether there is any causal relationship between change in the interest rate and changes in the import quantities of forest products in Korea. And the second objective is to evaluate the dynamics of the impacts of the interest rate change on the forest products import quantities in Korea. The relationship between the interest rate and the import quantity was represented by bivariate vector autoregressive model. Whether there is any causal relationship between change in the interest rate and changes in the import quantities of forest products was analyzed by the causality test. And the dynamics of the impacts of the interest rate change on the forest products import quantities were evaluated by variance decomposition analysis and impulse response analysis. The import quantity of forest products can be explained by the lagged interest rate variables and the lagged import quantity variables in Korea. Change in the interest rate causes change in the plywood import quantity in Korea. In the bivariate model of the plywood import quantity, after three months, the interest rate change accounts for about twenty percent of variation in the import quantity, and its own change accounts for about eighty percent of variation in the import quantity. On the other hand, the impact of a shock to the interest rate is significant for about six months on the import quantity of plywood in Korea. That is, if the interest rate change had an impact on the import quantity of plywood in Korea, it was only of a short-term nature.

• Journal of the Korea Society for Simulation
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• v.33 no.1
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• pp.1-17
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• 2024

Forest management is known to beneficially influence stand structure and wood production, yet quantitative understanding as well as an illustrative depiction of the effects of different management approaches on tree growth and stand dynamics are still scarce. Long-term management of beech forests must balance public interests with ecological aspects. Efficient forest management requires the reliable prediction of tree growth change. We aimed to develop a novel hybrid simulation approach, which realistically simulates short- as well as long-term effects of different forest management regimes commonly applied, but not limited, to German low mountain ranges, including near-natural forest management based on single-tree selection harvesting. The model basically consists of three modules for (a) natural seedling regeneration, (b) mortality adjustment, and (c) tree growth simulation. In our approach, an existing validated growth model was used to calculate single year tree growth, and expanded on by including in a newly developed simulation process using calibrated modules based on practical experience in forest management and advice from the local forest. We included the following different beech forest-management scenarios that are representative for German low mountain ranges to our simulation tool: (1) plantation, (2) continuous cover forestry, and (3) reserved forest. The simulation results show a robust consistency with expert knowledge as well as a great comparability with mid-term monitoring data, indicating a strong model performance. We successfully developed a hybrid simulation that realistically reflects different management strategies and tree growth in low mountain range. This study represents a basis for a new model calibration method, which has translational potential for further studies to develop reliable tailor-made models adjusted to local situations in beech forest management.