• Journal of Forest and Environmental Science
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• v.20 no.1
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• pp.40-50
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• 2004

This study was conducted to provide appropriate tending operation strategies for the natural deciduous forest, by the method of evaluating the stand quality, suggesting the removal plan for the undesirable trees, and predicting improvement cutting practice by tree quality evaluation. The results showed that average number of trees per ha was 717 stems, average DBH was 21.1cm. and average height was 13.6m. Canopy dominant species were in the order of Quercus serrata, Q. variabilis, Q. mongolica, Styrax obassia, and Ulmus davidiana var. japonica. Based on grades of four tree form factors for all tree in the study plots, we estimate the change of tree numbers. DBH and height with the improvement cutting by different tree grade. When the higher tree grade was applied to tending operation, the number of stem was decreased, but the values of DBH and height were not changed much, predicted to improve the stand quality.

• Journal of Korean Society of Forest Science
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• v.111 no.2
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• pp.302-310
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• 2022

Here we aimed to classify the major coniferous tree species (Pinus densiflora, Pinus koraiensis, and Larix kaempferi) by tree measurement information and machine learning algorithms to establish an efficient forest management plan. We used national forest monitoring information amassed over nine years for the measurement information of trees, and random forest (RF), XGBoost (XGB), and light GBM (LGBM) as machine learning algorithms. We compared and evaluated the accuracy of the algorithm through performance evaluation using the accuracy, precision, recall, and F1 score of the algorithm. The RF algorithm had the highest performance evaluation score for all tree species, and highest scores for Pinus densiflora, with an accuracy of about 65%, a precision of about 72%, a recall of about 60%, and an F1 score of about 66%. The classification accuracy for the dominant trees was higher than about 80% in the crown classes, but that of the co-dominant trees, the intermediate trees, and the overtopper trees was evaluated as low. We consider that the results of this study can be used as reference data for decision-making in the selection of thinning trees for forest management.

• Journal of Korean Society of Forest Science
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• v.104 no.4
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• pp.649-656
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• 2015

The objective of this study was to analyze the optimal thinning regimes for timber or carbon managements in Cryptomeria japonica stands of Hannam Experimental Forest, Korea Forest Research Institute. In solving the problem, PATH algorithm, developed by Paderes and Brodie, was used as the decision-making tool and the individual-tree/distance-free stand growth simulator for the species, developed by Kwon et al., was used to predict the stand growth associated with density control by thinning regimes and mortality. The results of this study indicate that the timber management for maximum net present value (NPV) needs less number of but higher intensity thinnings than the carbon management for maximum carbon absorption does. In case of carbon management, the amount of carbon absorption is bigger than that of timber management by about 6% but NPV is reduced by about 3.2%. On the other hand, intensive forest managements with thinning regimes promotes net income and carbon absorption by about 60% compared with those of the do-nothing option.

• Journal of Korean Society of Forest Science
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• v.110 no.4
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• pp.678-688
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• 2021

This study was conducted to provide growth characteristics and stand information in preparation for natural regeneration method and silvicultural treatment of seed tree method in Korean red pine stands by using the field inventoried data 18 years after the seed tree regeneration method in 2001 and analyzing the stand and sapling characteristics. The study area was located in the Research Forest of Kangwon National University, Chuncheon-si, Gangwon-do. In November 2018, we collected tree measurement factors, such as diameter at breast height (DBH), height, crown class, stem quality, tree age, and annual height increment on the established plots. We calculated the basal area, volume, height-diameter ratio (HD ratio), and additional stand density variables such as the relative density and %stocking to analyze the managed stands. The number of mother trees was 58 trees/ha, with a 17.7% stocking level, whereas the number of saplings was 2,330 trees/ha, with a 79.0% stocking level. In germination, the age distribution of saplings ranged from 2001 to 2007, with most belonging to 15-16 years. The development condition of saplings was 10 cm in DBH and 8 m in height. DBH and height were higher as the crown class is more dominant, and this difference was statistically significant in the analysis of variance and Duncan's multiple comparison test (p<0.0001). HD ratio ranged mostly between 80% and 90%, and more than 95% of sapling stems were of high quality, with a straight, unbroken top, non-sweep, and non-diseased stem. On average, the annual height increment of saplings was 21.9 cm at 1 year, 43.3 cm at 5 years, 54.3 cm at 10 years, and 64.3 cm at 15 years. The overall height growth with age increased smoothly. According to the analysis of covariance, the annual height growth by crown class differed significantly. The regression analysis parameters revealed that annual height growth increased with age and dominant crown class.

• Journal of Korean Society of Forest Science
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• v.99 no.1
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• pp.136-143
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• 2010

This study was conducted to provide basic information on the management of natural deciduous forests by presenting suitable stand density over time for natural deciduous forests in Pyungchang Area. The stand density index(SDI) for the sampling point was also computed. The cutting scenarios were adopted by considering the SDI estimated in the sampling point. And then, simulation cutting was enforced to the stand. Cutting scenarios consisted of three cutting levels, with the period of 5 years where each suitable cutting level of selection system will not have the SDI over the maximum SDI throughout 30 years and consider harvest after 30 years. As a result of the simulation cutting, it was found that removing 12% and 14% of basal area per each time kept proper stand density while removing 10% exceed to the adequate basis. From an economic point of view, it was concluded that removal 12% of basal area would be the most suit cutting level in selection system.

• Journal of agriculture & life science
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• v.43 no.6
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• pp.19-27
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• 2009

This study was carried out to obtain the basic model to estimate damage degree from the correlation analysis between forest fire and site environment factors and to clarify the restoration trends thorough multi-temporal survey by observing species diversity followed by various treatments at damaged forest area over time. From the derived model, the damage degree of forest fire was higher in the area of dense coniferous stands composed of simple story at the elevation of about 100m and 200m, and on steeper slope area over 30 degree. As results of this study, fire damaged trees are needed to cut down and a mixed stand with deciduous and coniferous species from the same area is desirable for the future species composition on fire damaged forest. Thus, site characteristics, local species, and mixed stands are the main consideration to enhance the vegetation recovery.

• Journal of Korean Society of Forest Science
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• v.112 no.3
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• pp.290-302
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• 2023

The aim of this study was to examine the changes in the initial tree growth characteristics of Q. variabilis planted in forest fire-damaged areas treated with soil moisturizers such as biochar and to identify the factors that affect tree growth. To evaluate the effectiveness of soil moisture treatment in the area planted with QV, an experimental plot was created according to the treatment method (spread and mix) and treatment ratio (0, 4, and 40 t/ha). The survival rate of QV was 20% higher in the treatment plot than in the control plot. The height and root collar diameter (RCD)growths of QV were high on the northern slope with spread treatment and on the southern slope with mix treatment. The relative growth rate (RGR) according to the soil moisturizer treatment method was higher in the mix treatment, showing a significant difference in RCD. The northern slope had a higher RGR and significant growth rate. This suggests that the growth improvement effect may depend on the soil moisturizer treatment method. The aspect or treatment method affectsthe drying conditions of the soil, which in turn affects its moisture content or nutrient dynamics. The present research results can be used to establish soil moisturizer treatment standards that are suitable for growth purposes. In addition, this study demonstrates that biochar treatment can be considered as an effective alternative to boost biomass and facilitate early restoration of forest fire-damaged areas.

• Journal of Korean Society of Forest Science
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• v.81 no.3
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• pp.287-298
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• 1992

The main purpose of this study is to obtain information on the factors influencing forest scenic beauty in order to make and manage scenic forest of recreation areas. 62 slides were taken for the study. Each photograph was independently judged by college students in 10 different major fields, with a total 264 observers after reliability test in the study. The ratings were scaled using a computer program developed by Brown & Daniel(1990). The results of rating scale analysis indicate that respondents' major field difference affects visual preference for forest scenic beauty. Similarly, with different sexual, forest visit frequency, and community type in childhood, people tend to rate their preference differently. The respondents' rating scale of relative scenic beauty of near-view forest scenes can largely be explained in terms of forest physical characteristics of forest landscape. Bare ground area and stash area are represented negative esthetic effects, while DBH, number of trees per hectare, sky area showed positive esthetic effects. These 6 variables in the model can be accounted for 74% of total variance in perceived forest scenic beauty. With this study result, it can be concluded that forest physical characteristics are significantly related to visual preference for near-view forest scenes.

• 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.

• Journal of Korean Society of Forest Science
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• v.67 no.1
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• pp.17-27
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• 1984

The Yangsan Forest Management Station (YFMS) of Korean German Forest Management Project (KGFMP), working with the 6 legal villages of Uljugun, Kyongnam, led the forest owners in the area to organize the Forest Management Cooperative (FMC) voluntairily for improvement of private forest management and fostered it as a model from May 1975 to Apr. 1984. YFMS sent out FMC a forest manager as a forestry expert carrying out the leading extension program at the equal position with forest owners and gave FMC financial, administrative and technical assitances. During the 6 years from 1977 to 1982, 4 FMC were founded and are being operated democratically. 228 forest owners have taken the membership of their own free will and the forestland of the members covers 2,567 ha equivalent to 57% of the total private forest in the area. During the period the total area of the planting and tending is 4,185 ha, this means that a member executed 3.1 ha of forest operations per year in average, showing the high willingness on forest operations. In addition the joint works have resulted in the joint properties equivalent to 27 million Won and it will be an important foundation for operation of FMC which is a forest owners's cooperative organization for improvement of private forest management in this area. The total expenditure spent for the fostering of FMC amounted to 497,587 thousand Won and 58% of them were charged from KGFMP funds, 27% from the forest owners and 15% from public funds. The expenditure for investment was 273,104 thousand Won and 59% of the sum were appropriated as subsidies at the national level. The forest owners charged 43% of that and this means that each member invested approximately 100 thousand Won to his forestland per year in average. For the extension program 169,503 thousand Won were spent and it can be explained that 5,885 Won were spent per ha a year. The organization of FMC operated autonomously in a democratic way and the horizontal and leading extension system, which aspects the human rights, were very much effective in fostering the cooperative organization of forest owners for improvement of private forest management.