• Journal of the Korean Wood Science and Technology
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• v.45 no.4
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• pp.399-408
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• 2017

Research on the rapid and accurate prediction of physical properties of wood using near-infrared (NIR) spectroscopy has attracted recent attention. In this study, partial least squares analysis was performed between NIR spectra and air-dried specific gravity of five domestic conifer species including larch (Larix kaempferi), Korean pine (Pinus koraiensis), red pine (Pinus densiflora), cedar (Cryptomeria japonica), and cypress (Chamaecyparis obtusa). Fifty different lumbers per species were purchased from the five National Forestry Cooperative Federations of Korea. The air-dried specific gravity of 100 knot- and defect-free specimens of each species was determined by NIR spectroscopy in the range of 680-2500 nm. Spectral data preprocessing including standard normal variate, detrend and forward first derivative (gap size = 8, smoothing = 8) were applied to all the NIR spectra of the specimens. Partial least squares analysis including cross-validation (five groups) was performed with the air-dried specific gravity and NIR spectra. When the performance of the regression model was expressed as $R^2$ (coefficient of determination) and root mean square error of calibration (RMSEC), $R^2$ and RMSEC were 0.63 and 0.027 for larch, 0.68 and 0.033 for Korean pine, 0.62 and 0.033 for red pine, 0.76 and 0.022 for cedar, and 0.79 and 0.027 for cypress, respectively. For the calibration model, which contained all species in this study, the $R^2$ was 0.75 and the RMSEC was 0.37.

• 한국방재학회:학술대회논문집
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• 2007.02a
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• pp.217-222
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• 2007

Since 1973, we attain a successful achievement of nation-wide afforestation such as a thick forest and heaped-up leaves. However, the higher of the formation density in forest, the more dangerous to be a large-scale forest fire whenever fire occurs. According to the type of forest in the country, 42% of the forest is occupied by conifer forest that are highly flammable, and the distribution of forest age is in a transition period from immature forest to mature one. And the structure is too weak to the forest fire for the occurrence and spread because there are too many scrub and shrub trees in the forest. As a matter of course, it is on the increase of the thinning-forest that can shift the forest structure from a weak on forest fire to a strong one nowaday. In other words, thinning-forest has primary purposes such as the promotion of producing forest trees, production of excellent timbers, and build-up of public forest area. Furthermore, in some reports, the reduction of ladder fuel by eliminating the vertical/horizontal fuel in a forest and ensuring spaces in the forest can decrease the occurrence of forest fire and the risk of spread of burning as by-effect. Therefore, this study is designed to clarify the relation with the risk of forest fire by an on-spat-investigation of the characteristics of forest composition on the thinning and the non-thinning area.

• Journal of Environmental Science International
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• v.24 no.2
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• pp.207-219
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• 2015

The purpose of this study is to show the geographical distribution and the temporal variation of the emission amount of biogenic volatile organic compounds(BVOCs) emanated from forests at Jeju Island. The total emission amount of BVOCs calculated by using the CORINAIR Methodology is $3612ton\;yr^{-1}$ at Jeju Island. More than half of BVOCs emissions is come from coniferous forest, and 45 per cent from broad leaved forest. The others is attributed to grassland. Of total emission of BVOCs, isoprene accounts for 28 per cent, monoterpene for 32 per cent, and other VOCs for about 40 percent, respectively. It can be shown that $3000{\sim}10000kg\;yr^{-1}$ of BVOCs is emitted at the zone with dense forest from an altitude of 500 m to the top of Mt. Halla, and less than $1500kg\;yr^{-1}$ at the zone an altitude of below 500 meters. The monoterpene emission is more than $1500kg\;yr^{-1}$ due to the existence of a colony of Abies koreana at the place with more than 1500 meters and a community of Pinus thunbergii and Cryptomeria japonica at the elevation of 500~700 m. In the case of isoprene emission, there is $1500{\sim}3000kg\;yr^{-1}$ at the zone of an elevation from 700 m to 1500 m due to dense broad leaved forest and very little of its emission at an elevation of more than 1500 meters because there is hardly broad leaved trees grown. In this study, emission of BVOCs according to the altitude above sea level is estimated under the situation of lack of the data for broad leaved tree. More detailed data and information for the distribution of broad leaved trees are needed in order to calculate more realistic BVOC emission.

• Journal of Korean Society of Forest Science
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• v.97 no.2
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• pp.165-170
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• 2008

Litterfall has been recognized an important part of the forest ecosystem production, playing a major pathway in energy flow and nutrient cycling through the ecosystem. This study was carried out to examine the quantity and components, temporal variation, and spatial heterogeneity of the litterfall in the mixed broadleaved-Korean pine forest. The data were collected from the 9ha permanent experimental plot, of which on the center area, i.e. $150m{\times}150m$, the total number of 319 circular litterfall traps with the size of $0.5m^2$ were established to collect falling litterfall. The results showed that the annual amount of litterfall was totalized 3,033.7 kg/ha, occupying broad-leaves of 39.3%, conifer-leaves of 29.5%, others of 18.5%, branches of 10.4%, and seeds of 2.3%. The peak point of the litterfall production was made at the end of September, proportionating 32.2% of total amount. The analysis of semivariogram revealed the existence of high spatial heterogeneity, calculated the scale of spatial heterogeneity ranged from 11.6 m to 29.1 m. The result of proportion (C/[Co+C]) showed that spatial heterogeneity of autocorrelation in total spatial heterogeneity were from 97.0% to 100%. The relatively heavy branches and others had significant differences in litterfall production between the areas of canopy gap and closed canopy in the 95% probability level, but the other components did not show statistical differences.

• Journal of the Korean Wood Science and Technology
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• v.10 no.3
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• pp.166-166
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• 1982

This study has been made to make an observation regarding present status of the coal mine props which is desperately needed for coal production, despite of great shortage of the timber resources in this country, and investigate the effects of diffusion process on the decay resistances of the mine props as applied preservatives of Malenit and chromated zinc chloride. The results are as follows. 1. Present status of the coal mine props Total demand of coal mine props in the year of 1975 was approximately 456 thousand cubic meters. The main species used for mine props are conifer (mainly Pinus densiflora) and hardwood (mainly Quercus). Portions between them are half and half. With non fixed specification, wide varieties of timber in size and form are used. And volume of wood used per ton of coal production shows also wide range from 0.017 cubic meter to 0.03 cubic meter. 2. Decay resistance test a) The oven dry weight decreased between untreated specimen and treated specimen has not shown any significantly, although it has shown some differences in average values between them. It may be caused by the shorter length of the test. b) The strength of compression test between untreated specimen and treated specimen has also shown the same results as shown in case of weight decrease. Reasons assumed are the same. c) The amounts of the extractives in one percent of sodium hydroxide (NaOH) between untreated and treated specimen have shown the large value in case of untreated specimen than that of treated. 3. The economical benifit between untreated and treated wood when applied in field has seen better in long tenn base in case of treated wood, although the primary cost of treated wood add a little bit more cost than that of the untreated wood.

• International Journal of Vascular Biomedical Engineering
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• v.2 no.2
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• pp.27-32
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• 2004

The objective of the present study is to visualize the steady and pulsatile flow fields in a branching model by using a high-resolution PIV system. A bifurcated flow system was built for the experiments in the steady and pulsatile flows. Harvard pulsatile pump was used to generate the pulsatile velocity waveforms. Conifer powder as the tracing particles was added to water to visualize the flow fields. CCD cameras($1K{\times}1K$(high resolution camera) and $640{\times}480$(low resolution camera)) captured two consecutive particle images at once for the image processing of several cross sections on the flow system. The range validation method and the area interpolation method were used to obtain the final velocity vectors with high accuracy. The results of the image processing clearly showed the recirculation zones and the formation of the paired secondary flows from the distal to the apex of the branch flow in the bifurcated model. The results also indicated that the particle velocities at the inner wall moved faster than the velocities at the outer wall due to the inertial force effects and the helical motions generated in the branch flows as the flow proceeded toward the outer wall. Even though the PIV images from the high resolution camera were closer to the simulation results than the images from the low resolution camera at some locations, both results of the PIV experiments from the two cameras generally agreed quite well with the results from the computer simulations. Therefore, instead of using the expensive stereoscopic PIV or 3D PIV system, the three-dimensional flow fields in a bifurcated model could be easily and exactly investigated by this study.

• Journal of environmental and Sanitary engineering
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• v.21 no.4 s.62
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• pp.39-48
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• 2006

In Juam basin, the ratio of non-point pollution source among pollutant loading of basin was significantly high, since the utilization level of land was high. In addition, the most pollutants were not treated and flowed out. In this study, the correlation between non-point source pollutants from the forest area and increasing algae was investigated. 1. Chl-a concentration flowed out to runoff from forest area and stream water was low as $0.1{\sim}20.3{\mu}g/{\ell}$ and $0.1{\sim}9.3{\mu}g/{\ell}$, respectively, and chl-a concentration ($0.1{\sim}28.5{\mu}g/{\ell}$) of branch stream was higher $5{\sim}7$ times than that of runoff from forest area. 2. In correlation between runoff from forest area and Juam lake water, annual chl-a concentration of area front Juam dam was higher twice than forest area. 3. In runoff from forest area within Juam basin, flagellate, green, diatom and blue algae occupied $33.0{\sim}41.7%$, $22.2{\sim}30.8%$, $17.3{\sim}22.5%$ and $13.7{\sim}17.6%$, respectively. 4. In runoff from forest area, both green and diatom algae were maintained constantly irrespectively of season, and flagellate algae dominated since August. 5. In characteristics by forest tree types, four types algae were inhabited in mixed forest, and flagellate algae were higher in conifer and broadleaf forest than in other area. And green algae in herbaceous forest were higher than other area.

• Journal of the Korean earth science society
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• v.36 no.1
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• pp.51-58
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• 2015

In order to understand the broad outline and palaeobotanical significances, the fossil woods from the Korean Peninsula were integrated through the literature surveys. Types and diversity of them are gradually increasing from Mesozoic to Cenozoic, especially increased sharply in Cenozoic. During the Early Mesozoic, six conifer taxa belonging to four genera were described, which corresponds to about 6% of the Daedong flora. Those of the Late Mesozoic are all conifers, consisting of fifteen taxa belonging to seven genera, which corresponds to about 29% of the Nakdong flora. During the Neogene, thirty four taxa belong to sixteen families were described. Those woods mostly consist of dicotyledon and have the greatest diversity compared to other geologic eras, which corresponds to about 83% of the Janggi flora. It is inferred that such a rapid increase of the silicified wood fossils in Neogene are due to the abundant presence of dicotyledon in floral composition and of pyroclastic rocks in strata, which are appropriate for preserving wood as fossils.

• Journal of Integrative Natural Science
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• v.1 no.3
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• pp.195-209
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• 2008

Some Korean terminologies on reproductive structures of seed plants in plant morphology, written incorrectly in many books, were analysed to propose accurately expressed terminologies. 31 books in areas such as general biology, plant biology, plant morphology, and biological dictionaries and glossaries were selected to analyse the accuracy of the terminologies for reproductive structures in gymnosperms, e.g., cone or strobilus, seed (or ovulate) cone and pollen cone, and conifer(s) or coniferous plants, and for flower structures in angiosperms, e.g., corolla, anther, filament, pistillate (or female) flower and staminate (or male) flower, apocarpous, and syncarpous. The definition and etymology of the terminologies were traced in 4 textbooks of plant anatomy and 2 dictionaries of biology and botany written in English. On the basis of the definition, etymology, and principles for terminology formation according to the International Organization for Standardization (ISO 704:2000), reasonably expressed Korean terminologies were proposed. All of the 8 terminologies examined in this study were included in the glossary of biological terminologies, published by the Korean Association of Biological Sciences in 2005, and designated as an editorial source for science and biology textbooks for middle and high schools by Ministry of Education in 2007. However, the only 1 of the 8 terminologies described in the glossary were consistent with the proposed expression in the present study. These inconsistencies indicated the need for a reassessment of this glossary of biological terminologies. The newly proposed terminologies would facilitate mutual understanding between teachers and students of plant biology.

• Journal of the Korea Furniture Society
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• v.20 no.2
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• pp.115-121
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• 2009

This study examined the emission characteristics and psychological effects of volatile organic compounds (VOCs) emitted from wooden boards made of Pinus densiflora and Chamaecyparis obtusa, conifer commonly found in korean forests. Boards made of those species were used to decorate interior of a test room. Different proportions of interior (20%, 40%, 60%, 80% and 100% against the entire interior of the room) were decorated. Electroencephalogram and VOCs in the test room were measured 24 hours after interior decorated. As the results, when 40% of interior of the room decorated with both species of boards, the largest amount of alpha wave was detected. For board made of P. densiflora, as the proportion of interior decorated increased both natural VOCs(NVOCs) and anthropogenic VOCs(AVOCs) were increased. on the other hand, When interior decorated with board made of C, obtusa, little differences in VOCs with different area of interior decorated was detected. Board made of P. densiflor emitted a slightly higher amount of AVOCs than boards made of C. obtusa. NVOCs emitted from board made of P. densiflora was three to fifteen times more than NVOCs emitted from board made of C. obtusa.