• Journal of Korean Society of Forest Science
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• v.34 no.1
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• pp.21-30
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• 1977

Japanese larch (Larix leptolepis) is one of main timber species in Korea that could find much plantation and growing stands on all over the country. It is thought to be in meaningful that a guiding diagram for density control of Japanese larch stands is made to estimate easily the density conditions in the quantitaive, ecological and economic viewpoint. Sample plots for this study are selected from the stands that have not been thinned in recent years, and mean height, mean diameter, dominant height, tree numbers per hectare and stem volume of mean tree are calculated from the each sample plots among total 165 plots In this study, especially, the theory of slenderness of mean tree are applied, that have been identified through the results of the spacing trial. Relative growth characteristics of this species are calculated from the general logistic curve and its formula is $Y=ax^b$. Relatwion between the measured items are found out as follows: 1. Relation between the mean height and tree numbers per hectare by slender class is showing the high correlation as table 1 and fig. 2, and between mean diameter and tree numbers per hectare is also high correlation as table 1 and fig 3. 2. The stem volume can be correctly estimated from height in case that slender class may be known, as showing in table 3 and fig. 4. 3. The stem volume can be more correctly estimated from the relation with $D^2H$ as formula, $Log_e\;V=0.9569\;Log_eD^2H-9.8431$, and relation between stem volume of single tree or volume per hectare and tree numbers per hectare are as following formulas: $Log_e$ stem volume=9.5026-1.6800 $Log_e$ tree numbers per hectare $Log_e$ stem volume per hectare=9.4911-0.6784 $Log_e$ tree numbers per hectare. Stem volume of mean tree, tree numbers per hectare and stem volume per hectare correspond to the mean tree height are calculated to slender class as table 5, 6, 7. Through the above steps, the diagram for density control of Japanese larch are produced as fig. 9. It is thought that this diagram could be applied to control the density of Japanese larch stands.

• Journal of Korean Society of Forest Science
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• v.78 no.2
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• pp.177-188
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• 1989

The habitat typing method of classification based on community has been developed on many forested areas in the ROCKY MOUNTAINS of WESTERN NORTH AMERICA, and is being used in providing an objective principle of guide for classification of forest sites, land classification, vertical distribution and multipurpose management of forest. I actually made a trial of forest habitat type classification - The methodology can be segmented into a number of tasks including reconnaissance, selection of stands to be sampled, location of plots, data gathering, preliminary and computer analysis, preparation of key- and map of habitat type and description for each habitat type in a view of forest management - on UNIVERSITY OF MONTANA FORESTS in order to examine whether its application is fit or not in korean forest circumstances : these are composed mainly of artificial forest and forest in the early stage of succession. The main results obtained from this study were summarized as follows 1. A hierarchical classification-Climax, Habitat type and Phases-of forest sites was developed using the habitat typing method of classification. 2. A diagnostic key is provided for field identification of the types based upon presence and number of indicator species, and forest managers could prepare a map of habitat type and classify forest habirat types by reference to it. 3. The classified habitat types were considered to be effective on providing an objective principle of guide for multipurpose management of forest including potential productivity for timber, feed productivity of forage and wildlife, selection of the right species in the right sites, application of method of treatment and so forth. 4. Forest habitat type classifications based upon extrapolation which used relict species and associated stands is considered to be suitable for korean forest circumstances and objective in studying potential vegetation, vertical and horizontal distribution of forest.

• Journal of Korean Society of Forest Science
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• v.73 no.1
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• pp.14-20
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• 1986

The processing times of the works, chainsaw felling, axe trimming and hand skidding to the corridor, by one-man-work method per single pole timber were investigated in the thinning young Japanese larch stand at the Training Forests of the Forest Work Tranining Center in Kangwon-do. The works were performed by a skilled worker with the craftman qualification and 69 trees were cut. Time was checked at intervals of 25/100 minute by the multimoment method and the worker's efficiency was evaluated for every cycle. Total working time was 8.11 hours of which 90% was for thinning work and 10% for cleaning work. Of the total working hours, 82.7% was net working time, 12.3% was general working time and 4.9% was non-valuated time. Of the net working time, 5.9hours, for only thinning, 20.9% was spent on moving to the feeling tree, 27.1% was spent on felling, 40.5% was spent on trimming and 11.5% was spent on skidding to corridor. Net chainsaw operating time was 0.94 hour which included 0.2 hour for cleaning work. Of the net chainsaw operating time, 0.94 hour, 66% was operating time and 34% was idle running time. The basic and general working times by DBH classes with application of 130% worker's efficiency calculated from regression equations were shown in table 1. For better practical using of this table, the simplified proposal was given in table 2.

• Journal of Korean Society of Forest Science
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• v.90 no.1
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• pp.90-104
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• 2001

This study is aimed to analyze and to evaluate the revegetation and soil conservation technology in desertification-affected sandy land, resulting from the project of "Studies on the desertification combating and sand industry development". Main native plants for combating desertification : The general characteristics of vegetation distribution in desertified regions are partially concentrated vegetation distribution types including the a) desert plants in low zone of desert or sanddune of depressed basin, b) salt-resistant plants around saline lakes, c) grouped vegetation with Poplar and Chinese Tamarix of freshwater-lakes, saline-lakes and river-banks, d) gobi vegetation of gravel desert and e) grassland and oasis-woods around the alluvial fan of rivers, etc. Generally, Tamarix ehinensis Lour., Haloxylon ammodendron Bunge., Calligonum spp., Populus euphratica Oliver., Elaeagnus angustifolia L., Ulmus pumila L., Salix spp., Hedysarum spp., Caragana spp., Xanthoceras sorbifolia Bunge., Nitraria tangutorum Bobr., Lespedeza bicolor, Alhagi sparsifolia Shap., Capparis spinosa L., Artemisia arenaria DC., etc. are widely distributed in desertified regions. It is necessary for conducting research in the native plants in desertified regions. Analysis of intensive revegetation technology system for combating desertification : In the wind erosion region, the experimental research projects of rational farming systems (regional planning, shelterbelts system, protection system of oasis, establishment of irrigation-channel networks and management technology of enormous farmlands, etc.), rational utilization technology of plant resources (fuelwood, medicinal plants, grazing and grassland management, etc.), utilization technology of water resources (management and planning of watershed, construction of channel and technology of water saving and irrigation, etc.), establishment of sheltetbelts, control of population increase and increased production technology of agricultural forest, fuelwood and feed, etc. are preponderantly being promoted. And in water erosion region, the experimental research projects of development of rational utilization technology of land and vegetation, engineering technology and protection technology of crops, etc. are being promoted in priority. And also, the experimental researches on the methods of utilization of water (irrigation, drainage, washing and rice cultivation, etc.), agricultural methods (reclamation of land, agronomy, fertilization, seeding, crop rotation, mixed-cultivation and soil dressing works, etc.) and biological methods (cultivation of salt-resistant crops and green manure and tree plantation, etc.) for improvement of saline soil and alkaline soil in desertified-lands are actively being promoted. And the international cooperations on the revegetation technology development projects of desertified-lands are sincerely being required.

• Journal of agricultural medicine and community health
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• v.46 no.3
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• pp.162-170
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• 2021

Objectives: This study was carried out to understand the seroprevalence and risk factors for severe fever with thrombocytopenia syndrome (SFTS) among the Korea National Park Service (KNPS) workers. Methods: We used the stored serum samples (763) and survey results collected from the previous investigation on scrub typhus and Lyme disease among the KNPS workers during 2016-2017. The serum samples were analyzed by double-antigen sandwich enzyme-linked immunosorbent assay, which was used to test the total antibody including IgG and IgM. Results: The SFTS seroprevalence among the KNPS worrkers was 1.4%. In multivariate logistic analysis, the national park exploration programs (odds ratio, 3.48; 95% confidence interval, 1.01-12.01) was significantly associated with the seroprevalence of SFTS. Conclusion: This study was the first serological study of SFTS among forestry workers in South Korea. Although the KNPS workers are at a high-risk group of SFTS, the prevention activities related to the working environment and habit was insufficient. Thus, systematic prevention education and training for the KNPS workers need to be strengthened.

• Journal of Korean Society of Forest Science
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• v.108 no.3
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• pp.440-453
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• 2019

This study was carried out to investigate the effect of watching a two-dimensional (2D) forest video and a virtual reality (VR) forest video on stress reduction in adults. Experiments were conducted in an artificial climate room, and 40 subjects participated. After inducing stress in the subjects, subjects watched a 2D gray video, 2D forest video, or VR forest video for 5 mins. The autonomic nervous system activity was evaluated continuously in terms of measured heart rate variability during the experiment. After each experiment, the subject's psychological state was evaluated using a questionnaire. The 2D forest video decreased the viewer's stress index, increased HF, and reduced heart rate compared with the 2D gray video. The VR forest video had a greater stress index reduction effect, LF/HF increase effect, and heart rate reduction effect than the 2D gray video. Psychological measurements showed that subjects felt more comfortable, natural, and calm when watching the 2D gray video, 2D forest video or VR forest video. We also found that the 2D forest video and VR forest video increased positive emotions and reduced negative emotions compared to the 2D gray video. Based on these results, it can be concluded that watching the 2D forest and VR forest videos reduces the stress index and heart rate compared with watching the 2D gray video. Thus, it is considered that the 2D forest video increases the activity of the parasympathetic nervous system, and the VR forest video increases the activity of the sympathetic nervous system. The increased activity of the sympathetic nervous system upon watching the VR forest video is judged to be positive sympathetic nerve activity, such as novelty and curiosity, and not negative sympathetic activity, such as stress and tension. The results of this study are expected to be the basis for examining the visual effects of forest healing, with hope that the utilization of VR, the technology of the fourth industrial revolution in the forestry field, will broaden.

• Korean Journal of Plant Resources
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• v.32 no.2
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• pp.160-169
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• 2019

The this study was carried out to investigate the growth characteristics of wild-simulated ginseng by direct seeding and transplanting cultivation for develop standard cultivation techniques of wild-simulated ginseng. Bonghwa experimental field were confirm to be suitable location environment for cultivation of wild-simulated ginseng. As a result of this study, the germination rate of wild-simulated ginseng was significantly highest when seed size was over 6.5 mm in the spot seeding cultivation. In the case of transplanting, survival rate was significantly increased when the diameter of root was over 10 mm, planting distance was 7 cm, and the thickness of soil covering was less then 2 cm. The result of growth characteristics of wild-simulated ginseng by cultivation type, growth of stem in spot seeding cultivation was showed significantly increased when seed size over 6 mm, seeding number was 3 grains, and the seeding distance was less then 5 cm. Strip seeding cultivation was showed significantly increased in stem and root growth when seeding distance was 30 cm grains and quantity of seeding was less then 23 g. In the case of transplanting cultivation, it's was showed significantly increased in stem growth when diameter of root was over then 10 mm and direction of rhizome was top and bottom. The results of this study was that to clearly establish the techniques of cultivation of managements and it's will be suggest contribute to the industrial activation of wild-simulated ginseng.

• Journal of Korean Society of Forest Science
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• v.100 no.3
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• pp.352-358
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• 2011

Field Cage plots ($1m{\times}1m{\times}1m$) were established (7 units) to find the lowest limit time about the tending of red pine forest (Pinus densiflora) which can no longer be used as a habitat by Monochamus alternatus, vector insect of pine wilt disease at the experimental forest of the southern forest research center of the Korea forest research institute in February in 2010. Thinning slashes (length, 1 m; diameter, 5~10 cm) tended at the different times were put in cages, and 4~6 couples of adult M. alternatus were put into each the cage in June. Presence or absence the larval entrance holes and larval were determined in November in 2010. Incase of the combination 24, 18, 12 and 6-month-old thinning slashes from thinning times to the time of adult emergence inside a single cage, larval entrance holes were found in the 6-month-old and 12-month-old thinning slashes but larvae were found only in the 6-month-old thinning slashes (treatment 1). In case of the combination 24, 18, 15 and 12-month-old thinning slashes inside a single cage, larval entrance holes were found in the 15-month-old and 12-month-old thinning slashes but larvae were found only in the 12-month-old (treatment 2). When 24, 18, 15, 12 and 6-month-old thinning slashes with treated dry and humid condition were put separately inside each cage, larval entrance holes were found in the 18, 15, 12, 6-month-old thinning slashes without the relation of the dry and humid conditions. But larvae were found in the 15, 12, 6-month-old thinning slashes in the dry conditions and only in the 6-month-old thinning slashes in the humid conditions. Results indicated the lowest limit time which can no longer be used as a habitat by M. alternatus is before 24 month from the time of adult emergence.

• Journal of Digital Convergence
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• v.20 no.4
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• pp.147-157
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• 2022

This study tried to propose a smart farm technology strategy suitable for the domestic situation, focusing on the differentiation suitable for the domestic situation of ICT technology. In the case of advanced countries in the overseas agricultural industry, it was confirmed that they focused on the development of a specific stage that reflected the geographical characteristics of each country, the characteristics of the agricultural industry, and the characteristics of the people's demand. Confirmed that no enemy development is being performed. Therefore, in response to problems such as a rapid decrease in the domestic rural population, aging population, loss of agricultural price competitiveness, increase in fallow land, and decrease in use rate of arable land, this study aims to develop smart farm ICT technology in the future to create quality agricultural products and have price competitiveness. It was suggested that the smart farm should be promoted by paying attention to the excellent performance, ease of use due to the aging of the labor force, and economic feasibility suitable for a small business scale. First, in terms of economic feasibility, the ICT technology is configured by selecting only the functions necessary for the small farm household (primary) business environment, and the smooth communication system with these is applied to the ICT technology to gradually update the functions required by the actual farmhouse. suggested that it may contribute to the reduction. Second, in terms of performance, it is suggested that the operation accuracy can be increased if attention is paid to improving the communication function of ICT, such as adjusting the difficulty of big data suitable for the aging population in Korea, using a language suitable for them, and setting an algorithm that reflects their prediction tendencies. Third, the level of ease of use. Smart farms based on ICT technology for the development of the Industry6.0 (1.0(Agriculture, Forestry) + 2.0(Agricultural and Water & Water Processing) + 3.0 (Service, Rural Experience, SCM)) perform operations according to specific commands, finally suggested that ease of use can be promoted by presetting and standardizing devices based on big data configuration customized for each regional environment.

• Korean Chemical Engineering Research
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• v.61 no.2
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• pp.302-311
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• 2023

This study was conducted to evaluate the applicability of castor oil (CSO) as a natural wood preservative. CSO was treated into wood blocks prepared with domestic and imported wood species using a vacuum-pressure method, and then treatability, leachability and decay resistance of the CSO-treated wood blocks were examined. Although CSO was penetrated effectively into wood blocks of all wood species, the CSO-treatability was the highest in Western hemlock, followed by Japanese larch (LA), soft maple and Mongolian oak due to the difference of its anatomical structure. Except for LA, the more retained, the more leached during a saline water-immersing process for 48h. The use of ethanol added to reduce the viscosity of CSO affected negatively the treatability and leachability of wood blocks. Decay resistance, which was evaluated by the weight loss of wood blocks exposed against Fomitopsis palustris (FOP) and Trametes versicolor, of the CSO-treated/leached wood blocks was superior to that of control. Especially, most of wood blocks treated with preserving solution composed of only CSO (CSO-2) did not decayed and showed a very low weight loss against FOP. The decay resistance results from CSO retained in wood blocks after leaching. The retention of CSO could identify using the observation of X-ray microscope. Length of wood strips, which were treated with CSO-2 and then immersed in saline water for 2 weeks, hardly changed in all cutting directions. In addition, weight gain and length-swelling rate of the wood strips were extremely low compared to those of control. These results indicate that moisture resistance of the wood strips was improved by the CSO treatment. It is concluded that the treatment of CSO using a vacuum-pressure method provides the decay resistance and dimensional stability of wood, and thus CSO can be used as a natural wood preservative on various indoor and outdoor circumstances.