• Journal of the Korean Association of Geographic Information Studies
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• v.17 no.4
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• pp.69-85
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• 2014

Carbon stocks of NFI plots can be accurately estimated using field survey information. However, an accurate estimation of carbon stocks in other unsurveyed sites is very difficult. In order to fill this gap, various spatial information can be used as an ancillary data. In South Korea, there is the 1:5,000 forest type map that was produced by digital air-photo interpretation and field survey. Because this map contains very detailed forest information, it can be used as the high-quality spatial data for estimating carbon stocks. In this study, we compared three upscaling methods based on the 1:5,000 forest type map and 5th national forest inventory data. Map algebra(method 1), RK(Regression Kriging)(method 2), and GWR(Geographically Weighted Regression)(method 3) were applied to estimate forest carbon stock in Chungcheong-nam Do and Daejeon metropolitan city. The range of carbon stocks from method 2(1.39~138.80 tonC/ha) and method 3(1.28~149.98 tonC/ha) were more similar to that of previous method(1.56~156.40 tonC/ha) than that of method 1(0.00~93.37 tonC/ha). This result shows that RK and GWR considering spatial autocorrelation can show spatial heterogeneity of carbon stocks. We carried out paired t-test for carbon stock data using 186 sample points to assess estimation accuracy. As a result, the average carbon stocks of method 2 and field survey method were not significantly different at p=0.05 using paired t-test. And the result of method 2 showed the lowest RMSE. Therefore regression kriging method is useful to consider spatial variations of carbon stocks distribution in rugged terrain and complex forest stand.

• Journal of Korean Society of Forest Science
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• v.107 no.4
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• pp.344-350
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• 2018

This study was carried out to improve the forest management method considering the use of high value added timber in the natural broadleaf forests. For this purpose, the criteria for evaluating the quality grade of standing trees were established and applied to the oak stand in the central region of Korea. The evaluation factors of the grade were bending of stem, branch, stem damage, and other defects. If the logs are divided into 2.1 m units and three logs up to 6.3 m are available, they are classified as Grade I (G-I). If two logs are available, they are classified as Grade II (G-II), If only one log is available, it is classified as Grade III (G-III). When any log is not available as timber, it is classified as Grade IV (G-IV). As a result of applying the grade to the oak stand, G-I was 6.7 %, G-II was 28.0 %, G-III was 38.3 %, and G-IV was 27.0 %. The ratio of standing trees by oak species of higher than G-III was 88.2 % for Quercus acutissima, 88.1 % for Q. variabilis, 83.5 % for Q. serrata, 56.3 % for Q. aliena, and 50.3 % for Q. mongolica, respectively. The G-IV ratio for Q. variabilis and Q. mongolica tended to decrease with increasing diameter at breast height. The order of major defect affecting the grading level was bending of stem > branch > stem damage > other defects. Considering the grade level and oak species distribution, it was concluded possible to produce high quality hardwood timber when we concentrate forest tending techniques on Q. acutissima and Q. variabilis stand. In order to improve the accuracy of grading, it is necessary to continuous complement through the monitoring research for evaluation factors.

• Journal of Korean Society of Forest Science
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• v.108 no.2
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• pp.177-188
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• 2019

The aim of our study was to identify the changing trends in the composition, structure, and spatial distribution of forest vegetation in Apsan Park, a representative urban forest in Daegu, South Korea. A vegetation survey was conducted in 1997 and 2016 using phytosociological methods, and a detailed vegetation map was created using the physiognomic dominant species. There were 22 vegetation types in both 1997 and 2016, but two of those types increased and two decreased. The total coverage per unit area ($100m^2$) of the component vegetation species increased from 163% in 1997 to 182% in 2016, and natural vegetation tended to be more than twice that of artificial vegetation. The average number of species decreased by seven from 25 in 1997 to 18 in 2016. Species diversity (H') increased only slightly from 1,654 in 1997 to 1,680 in 2016, while species dominance (D) decreased by 9% from 0.304 in 1997 to 0.276 in 2016. The similarity in the composition of the forest vegetation was about 78%, which was nearly the same. The life form spectrums of vascular plants changed from '$G-R_5-D_4-e$' in 1997 to '$MM-R_5-D_4-e$' in 2016 and the central dormancy type changed from geophytes (G) to megaphanerophytes (MM). The spatial distribution of the forest vegetation was reduced by approximately four times that of artificial vegetation. The number of forest landscape elements (patches) increased from 269 in 1997 to 294 in 2016, while the average area decreased by 12% from 5.8 ha in 1997 to 5.1 ha in 2016.

• Journal of Korean Society of Forest Science
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• v.108 no.1
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• pp.88-96
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• 2019

The purpose of this study is to understand when forest fire as a natural phenomenon becomes constructed as social issues in Korea; how the forest fire-related discourses in the editorials reflecting the social perceptions have been changed regarding the principal subject and the measures of the forest fire management; and whether the social perception on the forest fire affects the forest fire policy of the state. From the analysis of a total of 44 editorials related to forest fires from 1988 to 2017. By the using, in the forest fire-related editorials the social perceptions on forest fires are forest fire editorials categories, main keywords, contents of social perception on 'the main subject responsible for forest fire management,' 'forest fire prevention measures,' categorization, frequency analysis and context analysis of words used. It is found that in the first-period forest fire management measures were recognized as a part of the overall forest management. In the second period, the approaches of ecological management emerged on the part of forest fire management. As forest fires were managed as a type of social disaster during the third period, such perceptions were gradually reinforced that the state should protect the people from the forest fire. In the 3rd, 4th, and 5th National Forest Plan, the forest fire management policy of each period was focused in enlightening the general public, protecting forest resources ecosystems, and preventing loss of lives, respectively. As a result of the analysis of social perceptions and comparing them to the forest fire policies through the analysis of editorials on forest fires, it is found that the social perception on the forest fire and forest fire management plan has changed having interconnections.

• Journal of Korean Society of Forest Science
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• v.110 no.2
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• pp.129-140
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• 2021

The study investigates the correlation between the seasonal changes in the absorption of fine dusts and the fine structure of surface on each type of street tree, such as Quercus myrsinifolia, Quercus glauca, Quercus salicina, Camellia japonica, and Prunus × yedoensis in the southernareas of Korea. The absorption ranges of fine dust were 31.51~110.44 ㎍/cm² in January, 23.20~79.30 ㎍/cm² in November, 22.68~76.90 ㎍/cm² in May, and 9.88~49.91 ㎍/cm² in August. The absorption value was about 54.4% higher in January than in May. With the grooves and hairs on the leaf surface and lots of wax, Q. salicina seems related to the high absorption rate of fine dust for each fine dust particle size. The one with gloss and smooth leaf surface has a low amount of wax. C. japonica Prunus × yedoensisshowed a low absorption rate of fine dust in each season. Whereas the increase in porosity density, length, and leaf area size can be related to the reduced PM and increasedabsorption rate, the leaf surface roughness, total wax amount, and porosity width can be related to the increase in the PM absorption rate. There was also a high correlation between the total wax amount and absorption rate of the leaf surface at the size of PM_0.2 than PM₁₀ and PM_2.5. These results imply that the quantitative and qualitative trais of leaf, such as wax amounts and leaf surface,can increase the absorption of fine dusts, and the small-sized particles seem to be highly adsorbed with the high wax amounts.

• Journal of Korean Society of Forest Science
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• v.112 no.1
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• pp.83-92
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• 2023

This study was established to investigate the site environment of mixed forests in Korea and to estimate the growth and yield of stands using national forest resources inventory data. The growth of mixed forests was derived by applying the Chapman-Richards model with diameter at breast height (DBH), height, and cross-sectional area at breast height (BA), and the yield of mixed forests was derived by applying stepwise regression analysis with factors such as cross-sectional area at breast height, site index (SI), age, and standing tree density per ha. Mixed forests were found to be growing in various locations. By climate zone, more than half of them were distributed in the temperate central region. By altitude, about 62% were distributed at 101-400 m. The fitness indexes (FI) for the growth model of mixed forests, which is the independent variable of stand age, were 0.32 for the DBH estimation, 0.22 for the height estimation, and 0.18 for the basal area at breast height estimation, which were somewhat low. However, considering the graph and residual between the estimated and measured values of the estimation equation, the use of this estimation model is not expected to cause any particular problems. The yield prediction model of mixed forests was derived as follows: Stand volume =-162.6859+6.3434 ∙ BA+9.9214 ∙ SI+0.7271 ∙ Age, which is a step- by-step input of basal area at breast height (BA), site index (SI), and age among several growth factors, and the determination coefficient (R²) of the equation was about 96%. Using our optimal growth and yield prediction model, a makeshift stand yield table was created. This table of mixed forests was also used to derive the rotation of the highest production in volume.

• Ecology and Resilient Infrastructure
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• v.6 no.2
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• pp.79-88
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• 2019

In order to study the water quality status and its causal environmental factors, the water quality variables of chemical oxygen demand (COD), chlorophyll a (Chl a), Total phosphorus (TP), and total nitrogen (TN), the hydrogeomorphologic variables of water level fluctuation, total water storage, dam elevation, watershed area, and shoreline development index, and the land cover variables of forest, agricultural area, and urbanized area in the watershed were investigated in total 73 reservoirs with various operational purposes, water level fluctuation and geographical distribution in South Korea. The water quality was more eutrophic in the reservoirs of the more urbanized and agricultural area in the watershed, the low altitude, the narrow water level fluctuation, the narrowed watershed area, and the more circular shape. In terms of the purposes of reservoir operation, the reservoirs for agricultural irrigation were more eutrophic than the reservoirs for flood control. The results of the variable selection and path analysis showed that COD determined by Chl a and TP was directly affected by water level fluctuation and the shoreline development of the reservoirs. TP was directly affected by the urbanized area of the watershed which was related to the elevation of the reservoir. TP was also influenced by the water level fluctuation and the shoreline development. In conclusion, the eutrophication of the reservoirs in Korea would be influenced by the land use of the watershed, hydrological and geographical characteristics of the reservoir, water level fluctuation by the anthropogenic management according to the reservoir operation purpose, and the location of the reservoirs.

• Korean Journal of Environment and Ecology
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• v.38 no.1
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• pp.79-89
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• 2024

The purpose of this study was to evaluate the area adjustment criteria and methods of the feasibility study of national park plans by applying them to Hallyeohaesang National Park. As a result of the ecological-based assessment used to identify the adjustment target areas, the ecological-based assessment Grades I and II that can be considered for inclusion were analyzed as 10.0% and 40.4%, respectively. Grade V, which can be considered for release, was 9.9%. As a result of the inclusion and release suitability assessment, the area subject to inclusion was 35.150 km² (3.669 km² on land and 31.481 km² at sea), and the area subject to release was 0.071 km² on land. When local governments and residents request the release of a park area for public interest or convenience, the release can be considered as long as the total area does not change, which is called a mutual exchange. The release area determined by mutual exchange was 10.386 km². It was 146 times the area determined by the suitability assessment for release. Matching the areas released by the mutual exchange with the ecological-based assessment, 70.6% (7.321 km²) was in Grades I and II, which can never be released. As a result, it was determined that the area adjustment of the feasibility study of Hallyeohaesang National Park was based on a very limited application of the results of the ecological-based assessment or the release suitability assessment. Also, mutual exchange was the key to area adjustment of the feasibility studies of national parks.

• Journal of Korean Society of Forest Science
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• v.109 no.3
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• pp.259-270
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• 2020

Extreme weather events, such as heat and drought, have occurred frequently over the past two decades. This has led to continuous reports of cases of forest damage due to physiological stress, not pest damage. In 2014, pine trees were collectively damaged in the forest genetic resources reserve of Sogwang-ri, Uljin, South Korea. An investigation was launched to determine the causes of the dieback, so that a forest management plan could be prepared to deal with the current dieback, and to prevent future damage. This study aimedto 1) understand the topographic and structural characteristics of the area which experienced pine tree dieback, 2) identify the main causes of the dieback, and 3) predict future risk areas through the use of machine-learning techniques. A model for identifying risk areas was developed using 14 explanatory variables, including location, elevation, slope, and age class. When three machine-learning techniques-Decision Tree, Random Forest (RF), and Support Vector Machine (SVM) were applied to the model, RF and SVM showed higher predictability scores, with accuracies over 93%. Our analysis of the variable set showed that the topographical areas most vulnerable to pine dieback were those with high altitudes, high daily solar radiation, and limited water availability. We also found that, when it came to forest stand characteristics, pine trees with high vertical stand densities (5-15 m high) and higher age classes experienced a higher risk of dieback. The RF and SVM models predicted that 9.5% or 115 ha of the Geumgang Pine Forest are at high risk for pine dieback. Our study suggests the need for further investigation into the vulnerable areas of the Geumgang Pine Forest, and also for climate change adaptive forest management steps to protect those areas which remain undamaged.

• Journal of Korean Society of Forest Science
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• v.113 no.1
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• pp.31-39
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• 2024

This study was performed to determine the effects of Four seedling age classes ageon the characteristics of growth and nutrient uptake in Chamaecyparis obtusa container seedlings. Seedlings (1-1, 2-0, 2-1, and 2-2 seedlings) of C. obtusa grown in containers were harvested to measure specific leaf area, height (H)/root collar diameter (D) ratio, dry mass of aboveground (T)/root dry mass (R) ratio, and seedling quality index of seedlings. The specific leaf area was highest in 1-0 seedlings (30.48 cm² g^-1), whereas it decreased (from 28.62 cm² g^-1 to 23.59 cm² g^-1) with increasing seedling age. The H/D ratio increased with increasing seedling age (from 4.41 in 1-0 seedlings to 8.35 in 2-2 seedlings). The T/R ratio decreased as the seedling age increased (from 4.29 in the 1-0 seedling to 2.13 in the 2-1 seedling). The seedling quality index increased with increasing seedling age (from 0.10 for the 1-0 seedling to 3.06 for the 2-2 seedling). The carbon concentrations of seedling components (leaf, branches, stem, and roots) did not differ significantly with seedling age, whereas the nitrogen concentration of seedling components was the lowest in 2-1 seedlings, as no fertilizer was applied to discourage excessive growth of the seedlings. Phosphorus, potassium, and magnesium concentrations in 2-1 seedling components were not affected by the lack of fertilizer application. These results can be applied to determine the optimum morphological characteristics and nutrient management by seedling age in container- grown C. obtusa.