• Journal of Environmental Science International
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• v.31 no.11
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• pp.941-950
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• 2022

This study was conducted to provide data and stem information to establish a local volume table of Cryptomeria japonica in Jeju Island. Stem analysis was performed on 26 trees by selecting two average trees from each site of the 13 plots of C. japonica stands in 2021 and 2022. During the analysis stage, one outlier tree was rejected, and a total of 260 observations of the specific stem height of 25 trees were used. Of the seven major taper equation models applied for parameter estimation and statistical verification, the Muhairwe 1999 model was found to be the best fit and selected as the optimal model. Stem shape-related estimates were acquired through the selected model, and sectional measurements according to the Smalian formula applied at an interval of 10 cm from the height of the stem were used to develop a volume table. A paired t-test comparison between the C. japonica volume obtained from the present study and those selected from the current yield table by NIFoS(2020), revealed significant differences (p<0.05), highlighting the necessity of a local volume table for C. japonica in Jeju Island.

• Journal of Environmental Science International
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• v.33 no.7
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• pp.453-462
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• 2024

This study was carried out for the purpose of selecting the most appropriate taper equation for the actual stands of Pinus thunbergii in the southern coastal region of Korea and then developing a stem volume table to provide basic data for rational management. To develop a volume table of Pinus thunbergii in this region of Korea, 59 sample trees with various diameter distributions were selected and stem analysis was performed. As a result of stem analysis, two trees with abnormal diameter and height growth as the age increased were rejected, and 57 trees were analyzed. To develop the taper equation, seven major variable exponential equations were used, including Kozak 1988, 1994, 2001, 2002, Bi 2000, Muhairwe 1999, and Sharma and Parton 2009. As a result of parameter estimation and statistical verification, the Kozak 1988 model showed the highest goodness of fit with Fit I (Fit Index), RMSE 1.5620, Bias 0.0031, and MAD 1.0784. The diameter of each 10cm stem ridge for the selected model was estimated, and a stem volume table was produced using the mensuration of division (end area formula) using the Smalian equation. As a result of two-sample T-test for volume table of this study and current yield table, the volume for this study was found to be significantly larger at all observation points (p < 0.001). Even for the same tree species, it is judged that differentiated volume tables are needed for each growth environment characteristic.

• Korean Journal of Agricultural and Forest Meteorology
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• v.5 no.1
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• pp.11-17
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• 2003

pH value of sampled fogwater at source regions (above highway and road) in Yongin sites showed the lowest value and was increased after passing the forest stands. Changes of ion concentrations through the forest stands showed a lowering tendency at sampling sites. The fogwater passing the forest stands (Quercus mangolica and Pinus rigida) surrendered acid pollutants to crown and stem from the atmosphere. It was concluded that environmental moisture in the atmosphere is acidified in fogwater. The influence was extended to the pure zone, and the frequency of acid rain has increased. The forests are assumed to remove air pollutants because ion concentrations in fogwater decreased after passing the forests. The fogwater which functions as a local sink for pollutants (H$_2$SO$_4$, HNO$_3$, etc.) falling on plant surfaces is considered to effectively remove acid pollutants. But if the deposition of pollutants exceeds the capacity of purification, it would damage the forest ecosystem. Further investigation is necessary to identify tree species tolerant to acid pollutants.

• Journal of Korean Society of Forest Science
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• v.95 no.4
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• pp.398-404
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• 2006

This study was conducted to compare the biomass and annual net production between 60 to 70-year-old Quercus mongolica stand at 1,300m, 1,000m, and 800m from sea level in Mt. Joongwang. The total biomass and annual net production were 211.6 ton/ha and 12.7 ton/ha/yr in northern aspect and 200.3 ton/ha and 14.0 ton/ha/yr in southern aspect of 1,300m from sea level, 252.9 ton/ha and 17.3 ton/ha/yr in northern aspect and 212.2 ton/ha and 14.2 ton/ha/yr in southern aspect of 1,000m from sea level, and 256.7 ton/ha and 14.5 ton/ha/yr in northern aspect and 232.4 ton/ha and 14.6 ton/ha/yr in southern aspect of 800m from sea level. The obtained results showed significant differences in annual net production among the study stands with respect to altitude, while did not those with respect to aspect.

• Journal of agriculture & life science
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• v.43 no.2
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• pp.9-15
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• 2009

The objectives of this study was to obtain the basic information for reasonable management of soil ecosystem damaged by pine wilt disease. Soil temperature and moisture content were $15.3{^{\circ}C}$ and 11.5% at whole-cut site, $14.4{^{\circ}C}$ and 13.5% at partial-cut site, and $13.7{^{\circ}C}$ and 14.8% at control site, respectively. The content of soil organic matter throughout the study period ranged from 2.11 to 2.64% at whole-cut site, 2.26 to 3.33% at partial-cut site, and 2.27 to 3.10% at control. Soil respiration rates showed seasonal fluctuations increasing in summer, which showed positive correlations between soil respiration and soil temperature. Average soil respiration were 0.24, 0.36 and $0.32gCO_{2}/m^{2}/hr$ at whole-cut site, partial-cut site, and control, respectively. $Q_{10}$ values ranged from 2.39 to 2.68 at Pinus densiflora stands damaged by pine wilt disease. Annual soil respiration rate at whole-cut site, partial-cut site and control were 8.1, 15.6 and $14.6tCO_{2}/ha/yr$, respectively.

• Journal of Korean Society of Forest Science
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• v.96 no.6
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• pp.639-643
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• 2007

The use of forest biomass resources produced by forest tending and residual forest biomass that was not gathered on commercial thinning or cutting area was estimated to be come into the spotlight as bioenergy sources in these days of new high oil price. With considering these problems, This study was investigated about possibility with biomass calculation and convertibility to fossil fuel in these area. Total forest tending area in the year 2005 was 294, 115 ha and the yield gathered from these area was $143,747m^3$. It is equivalent to biomass of 115,000 ton and caloric value of 533,199Gcal. However, the potential and additional yield that is residual in forest stands was 2,483,000 ton. It is equivalent to 11,133 billion won of oil which is 20 times of the actual yield produced by forest tending. Therefore, these amount of biomass has a substitution effect of the fossil fuel. Moreover, the residual biomass that is not gathered at commercial thinning and cutting area was 475,000 ton. It is equivalent to 2,206,235 Gcal of heating value and about 2,211 billion won of oil. This potential amount could be a new energy source to be a substitution effect of fossil fuel. It is time to be interested in the forest biomass as a renewable and environment-friendly resource and its substitution effect of fossil fuel.

• Journal of Korean Society of Forest Science
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• v.112 no.2
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• pp.209-216
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• 2023

This study aimed to use national forest inventory data to develop a forest productivity index and yield prediction model of a Tilia amurensis stand. The site index displaying the forest productivity of the Tilia amurensis stand was developed as a Schumacher model, and the site index classification curve was generated from the model results; its distribution growth in Korea ranged from 8-16. The growth model using age as an independent variable for breast height and height diameter estimation was derived from the Chapman-Richards and Weibull model. The Fitness Indices of the estimation models were 0.32 and 0.11, respectively, which were generally low values, but the estimation-equation residuals were evenly distributed around 0, so we judged that there would be no issue in applying the equation. The stand basal area and site index of the Tilia amurensis stand had the greatest effect on the stand-volume change. These two factors were used to derive the Tilia amurensis stand yield model, and the model's determination coefficient was approximately 94%. After verifying the residual normality of the equation and autocorrelation of the growth factors in the yield model, no particular problems were observed. Finally, the growth and yield models of the Tilia amurensis stand were used to produce the makeshift stand yield table. According to this table, when the Tilia amurensis stand is 70 years old, the estimated stand-volume per hectare would be approximately 208 m³ . It is expected that these study results will be helpful for decision-making of Tilia amurensis stands management, which have high value as a forest resource for honey and timber.

• Journal of Korean Society of Forest Science
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• v.107 no.2
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• pp.174-183
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• 2018

This study aims to make the stand density management diagram which is useful for establishing stand density management system in Chamaecyparis obtusa forest. By using 216 sample plots to estimate Yield-Density relationship ($R^2=0.743$), the stand density management diagram was modeled by the estimated parameters. As a result of this diagram, after planting 3,000 trees per hectare the mortality rate of this unthinned C. obtusa stands over 80 years was estimated to be equal to $12.0{\sim}18.1trees{\cdot}ha^{-1}{\cdot}year^{-1}$, and stand volume was $463.1{\sim}695.4m^3{\cdot}ha^{-1}$, and stand density was $1,555{\sim}2,038trees{\cdot}ha^{-1}$. Developed stand density management diagram for C. obtusa is effective to establish the management criteria and production objective. Therefore, this study allowed us to make the optimal forest working plan.

• Korean Journal of Environment and Ecology
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• v.32 no.2
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• pp.185-202
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• 2018

Many ecological studies regarding forest succession, which is the process of arriving at climax forest through ecological changes, have suggested that Carpinus laxiflora is the leading tree type of the climax forest of temperate zone in South Korea. However, most of these studies on C. laxiflora forest have focused on vegetation structure and succession process in specific areas or regional physiognomical forest communities, and thus some may question whether it is rational to consider C. laxiflora forest as the climax forest in South Korea's temperate forest zone. The purpose of this study was to analyze the vegetation classification, species composition, and stratum structure and to investigate the succession tendency with the vegetation data collected from C. laxiflora forests in 75 quadrates in 17 mountains between 2014 and 2017. We used the phytosociological method to analyze the vegetation structure and the importance value to analyze the stratum structure. The results showed the floristic composition of 6 vegetation units and 9 species groups. The hierarchy of the C. laxiflora community group was represented by the Ulmus laciniata community, Corylus heterophylla community (subdivided Quercus aliena group and Corylus heterophylla typical group), and Rhododendron schlippenbachii community (subdivided Fraxinus chiisanensis group, Carpinus tschonoskii group, and Rhododendron schlippenbachii typical group). Successional tendency of C. laxiflora forest based on the importance of each layer is predicted to be the total of three types such as to maintain the stand (vegetation units 2, 3, and 6), to success the Carpinus cordata forest (vegetation units 1 and 4), and to success Quercus acuta forest (vegetation unit 5).

• Korean Journal of Agricultural and Forest Meteorology
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• v.25 no.3
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• pp.117-128
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• 2023

Tree dieback in Geumgang pine forest has occurred in Uljin and Bonghwa since the 2010s. In order to identify status of tree dieback and prevent further damages, a monitoring project for tree dieback in Geumgang pine forest had been launched by Southern regional office of forest service in 2020. This study was conducted to understand the characteristics of tree dieback occurrence and assess the high risk areas using the occurrence data in the project. Pine tree dieback occurred frequently in areas with mountain ridges in high elevation, dry south-facing slopes, mature stands, and high temperature rise in winter. Furthermore, the result of risk assessment showed that 6.2 percent(5,294ha) of Geumgang pine forest(85,000 ha) in total study area are at high risk of tree dieback. As the pine trees in the high risk area are prone to experience the dieback due to temperature and drought-related extreme weather events, regular forest management activities are needed to reduce the drought stress of pine trees. Forest health management for the pine forest with high protection priority can be also useful strategy to counter the risk of decline. This results can be used as the basic information for the adaptive forest management to climate change.