• Journal of Korean Society of Forest Science
• /
• v.89 no.2
• /
• pp.256-259
• /
• 2000

D.B.H., height, crown length, crown width, crown form, crown area, and crown volume of dead and live trees were measured and the discriminant analysis was conducted to assess individual tree risk-rating in the pine forest seriously infested by the pine needle gall midge. Thecodiplosis japonensis. Crown length, crown form, crown area, and crown volume of live tree were significantly higher than those of dead tree, while D.B.H. and tree height were not different significantly. These results represent that the trees with higher and wider crown and larger crown volume have relatively higher probability to survive from the infestation by the pine needle gall midge. Variables selected in the functions of discriminant analysis were crown area, ratio of crown length, crown form, ratio of crown volume to crown area, and ratio of crown width.

• Horticultural Science & Technology
• /
• v.32 no.4
• /
• pp.440-447
• /
• 2014

For this analysis, canopies of slender-spindle 'Hongro'/M9 apple trees were divided into 4 positions: upper, lower, exterior, and interior parts. The photosynthetic rate was highest in the external part of the upper canopy of the tree, where it was 4.5 times higher than in the internal part of the lower canopy. This difference was closely associated with differences in light penetration based on canopy position. Analysis of leaf growth characteristics showed that the leaves situated in the internal part of the canopy were larger and thinner than those in the external part of the canopy. The difference in leaf thickness was mainly due to thickness of the primary layer of palisade tissues (68.5 and $110.3{\mu}m$ for internal and external leaves, respectively). Fruit weight and quality were closely related to the extent of light penetration. Fruit weight, soluble solid content, and red skin color were higher in the fruits from the external part of the canopy. Thus, fruit maturity was delayed in the internal part of canopy. The fruit skin and wax layer were thicker in fruits from the internal canopy than in those from the external canopy. Therefore, our results indicate a need for improved light penetration in internal parts of the canopy and for split harvesting depending on maturity at different canopy positions.

• Journal of Korean Society of Forest Science
• /
• v.100 no.3
• /
• pp.402-407
• /
• 2011

The objectives of this study were to analyze the crown vertical structure, crown bulk density, and to develop regression models for predicting crown fuel load using the data from 10 destructively sampled Pinus densiflora trees in Bonghwa, Gyeongbuk. The fuel loads were observed higher in the middle portion of the vertical distribution of crown followed by the lower portion and upper portion of Pinus densiflora, respectively. Approximately 25% crown fuel load was found in the needle while 33% was observed in the branches with <1 cm diameter with a total of 58% available fuel loads. The average crown bulk density was $0.45kg/m^3$, and $0.27kg/m^3$ of this was available in the needles and branches with <1 cm diameters. The resulting models in linear equations were able to account for 84% and 88% of the observed variation, while the allometric equations with diameter at breast height as the single predictor showed better results to account for 90% and 95% of the observed variation in the available crown fuel loads and total crown fuel loads, respectively. The suggested equations in this study could provide quantitative fuel load attributes for crown fire behavior models and fire management of red pine stands in Bonghwa areas.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.34 no.10
• /
• pp.1393-1401
• /
• 2010

In this experimental study, we have examined the correlation between a human carpal motion and a surface electromyogram. The carpal motion patterns have been identified and the main muscles involved in the carpal motion have been determined by investigating the anatomical structure of a carpal. The torque acting against the carpal motion has been applied by using a device for carpal rehabilitation training, and the surface electromyogram signal corresponding to the torque at the main muscles has been measured. The root-mean-square (RMS) magnitude of the surface electromyogram signal has been calculated and used to analyze the correlation between the surface electromyogram signal and carpal motion. The experimental results have proved that for carpal torque values below $0.1\;N{\cdot}m$, the RMS magnitude of the surface electromyogram signal is linearly proportional to the carpal torque magnitude and that the carpal torque magnitude is linearly proportional to the cross-sectional area of the carpal muscles. Further, the analysis of the contribution of each muscle to the carpal motion has shown that the contribution of the most dominant muscle is consistently 60%. These three results can be applied to develop more sophisticated devices or robots for carpal rehabilitation training.

• Journal of the Korean Association of Geographic Information Studies
• /
• v.17 no.1
• /
• pp.1-12
• /
• 2014

Crown fire, the main propagation type of large forest fire, has caused extreme damage with the fast spread rate and the high flame intensity. In this paper, we developed the probability equation to predict the crown fires using the spatial features of topography, fuel and weather in damaged area by crown fire. Eighteen variables were collected and then classified by burn severity utilizing geographic information system and remote sensing. Crown fire ratio and logistic regression model were used to select related variables and to estimate the weights for the classes of each variables. As a results, elevation, forest type, elevation relief ratio, folded aspect, plan curvature and solar insolation were related to the crown fire propagation. The crown fire propagation probability equation may can be applied to the priority setting of fuel treatment and suppression resources allocation for forest fire.

• Journal of Korean Society of Forest Science
• /
• v.99 no.1
• /
• pp.52-56
• /
• 2010

Crown fuel characteristics such as crown bulk density, crown base height, and fuel moisture content of Japanese red pine were analyzed. Ten trees in Mt. Palgong at Daegu, were destructively sampled and their crown fuels were weighed separately for each fuel category. Fuel content of live and dead crown component were 53%, and 15.3%, respectively. Foliar moisture content was 56%. Needles and twigs with diameter less than 1cm diameter accounted for 16.2%, 55% of total and crown fuel load. Average crown bulk density of Japanese red pine was 0.24 kg/$m^3$, effective crown fuel bulk density was 0.1325 kg/$m^3$.

• Journal of Korean Society for Geospatial Information Science
• /
• v.20 no.1
• /
• pp.83-91
• /
• 2012

Crown density, which is defined as the proportion of the forest floor concealed by tree crown, is important and useful information in various fields. Previous methods of measuring crown density have estimated crown density by interpreting aerial photographs or through a ground survey. These are time-consuming, labor-intensive, expensive and inconsistent approaches, as they involve a great deal of subjectivity and rely on the experience of the interpreter. In this study, the crown density of a forest in Korea was estimated using KOMPSAT-2 high-resolution satellite images. Using the image segmentation technique and stand information of the digital forest map, the forest area was divided into zones. The crown density for each segment was determined using the discriminant analysis method and the forest ratio method. The results showed that the accuracy of the discriminant analysis method was about 60%, while the accuracy of the forest ratio method was about 85%. The probability of extraction of candidate to update was verified by comparing the result with the digital forest map.

• Journal of Korean Society of Forest Science
• /
• v.100 no.2
• /
• pp.266-272
• /
• 2011

This study was conducted to analyze the characteristics of crown fuel biomass and to develop allometric equations for the estimation of crown fuel biomass by subjectively categorized the crown component in Pinus densiflora stands. A total of ten representative trees were destructively sampled in Youngju region. Crown fuel were weighed separately for each fuel category by size class. The results of this study showed that foliar moisture content was 119% while the average crown moisture content was 105.3%. The crown fuel/total fuel loading ratio was 30%, needles and twigs with less than 1 cm diameter accounted 50.3% for its fuel/crown fuel loading ratio. Adjusted multiple coefficient of determination of suggested allometric equations ranged from 0.6846 to 0.9246 for crown fuel biomass, 0.8308 for crown volume.

• Journal of dental hygiene science
• /
• v.15 no.5
• /
• pp.659-665
• /
• 2015

A wide variety of methods have been used to control Dental Unit Waterline (DUWL) contamination. Among the methods, flushing is mainly used because it is simple and easy to use. Generally, flushing of DUWL for 20 or 30 sec before using high speed handpieces or scalers is recommended. However, the appropriateness of flushing time was not investigated thoroughly. The purpose of this study was to check the effective time of flushing for decreasing bacterial contamination. Seven dental unit chairs were randomly selected in student clinical simulation laboratory for this experiment. DUWLs were continuously flushed and water samples were collected at an interval of 30 seconds for 15 minutes. From five dental unit chairs, water samples were collected every 10 seconds for 1 minute. Bacterial levels in water samples were examined by the culture method on R2A plates. After 10 second flushing of DUWLs, the number of bacteria significantly reduced and decreased continuously up to 40 seconds. However, even after the water was flushed for 15 minutes, the bacterial contamination level was not reduced below recommended bacteria level, 200 CFU/ml. In addition to flushing, the periodic chemical disinfection is required to control the DUWL water to the recommended level.

• Journal of Korean Society of Forest Science
• /
• v.85 no.4
• /
• pp.557-564
• /
• 1996

Based on stem analysis as well as branch analysis data of each tree from 8 plots of circle clear-cutting and 1 biomass plot in Changbai Mountain area, located in Northeast of China, the effective crown form of Changbai larch(Larix olgensis H.) plantation were studied by using the approach of crown curve. The results indicated that the cross-section forms of effective crown were stable and showed approximate circle for different tree size. Because the effective crown was on upper position of the canopy and its form reflects crown architecture under non-competition condition, the architecture is mainly affected by species hereditary feature. Therefore, for the specified species the effective crown form was thought to be relatively stable. The effective crown form of tree was neither related to the tree size within stand nor to the stand condition for different stand. The total effective crown curve of larch plantation could be characterized by using mean effective crown taper.