• Journal of the Korean Wood Science and Technology
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• v.45 no.5
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• pp.559-571
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• 2017

This study was conducted to determine the adhesive performances of plywoods affected by layering direction and the amounts of thermoplastic films. The face and back layers of veneer were hardwood species (Mixed light hardwood) and core layer veneer was radiata pine (Pinus radiata D. Don). Thermoplastic film used as adhesive were polypropylene (PP) film and polyethylene (PE) film. Thermal analysis and tensile strength were investigated on each films. As a result, the melting temperature of PP and PE films were $163.4^{\circ}C$ and $109.7^{\circ}C$, respectively, and the crystallization temperature were $98.9^{\circ}C$ and $93.6^{\circ}C$, respectively. Tensile strength and elongation of each films appeared higher on the width direction than length direction. Considering the characteristics of the thermoplastic films, the test for the amount of film used was carried out by layering film to the target thickness on veneer. The effecting of layering direction of film on plywood manufacturing was conducted by laminating in the length and width directions of the film according to the grain direction of veneer. Tensile-shear strength of plywood in wet condition was satisfied with the quality standard (0.7 MPa) of KS F 3101 when the film was used over 0.05 mm of PP film and over 0.10 mm of PE film. Tensile-shear strength of plywood after cyclic boiling exceeded the KS standard when PP film was used 0.20 mm thickness. Furthermore, higher bonding strength was observed on a plywood made with width direction of film according to grain direction of veneer than that of length direction of film. Based on microscopic analysis of the surface and bonding line of plywood, interlocking between veneers by penetration of a thermoplastic film into inner and cracks were observed.

• Journal of Mushroom
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• v.2 no.2
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• pp.88-96
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• 2004

This study was executed to decide the physiological characteristics of Ferule mushroom. Four strains of Ferule mushroom were tested to select a superior strain in its mycelial growth. The pertinent substrates, temperature and pH ranges for the growth of selected strain were determined. And then, the wood rotting ability and type of the Ferule mushroom were determined. The superior strain F-2 among four strains was selected, on the basis of its vegetative mycelial growth and density on agar media. Mycelial growth of F-2 was the best on MYPA among other tested synthetic or semi-synthetic media. The temperature range for pertinent mycelial growth was about $25{\sim}34^{\circ}C$ and best at $30^{\circ}C$. The optimum pH range on MYPA was 5.0~6.0. The mycelial growth was mostly stimulated by soluble starch at cont. 1% (w/w) and secondly, maltose among several carabon sources and by mixed solution of YE(0.25%) and ME(0.25%) but not by ME alone. Cell thining and erosion of Pinus rigida wood by the mycelia of Ferule mushroom were found only on a few cell but largely at wood block test, indicating that the softwood rotting ability of Ferule mushroom mycelia was not so good. The result of polarized light microscopy appeared that cellulose of some tracheides showing the S3 layer lost brifringence was degraded by Ferule mushroom. But only part of cellulose of P. rigida wood was degraded by Ferule mushroom, because most of wood cells continued to showing briefingence. A largely degraded ray parenchyma and longitudinal parenchyma cell and partly thinning and erosion of hardwood(Quercus serrata) cell was found and it indicates that the rotting ability of Ferule mushroom mycelia on hardwood was higher than on softwood. It could be concluded that the difference in the wood rot by Ferule mushroom between the hardwood and softwood was made by the difference of chemical constitutions between them, especially in the contents and the types of lignin. Ferule mushroom was considered as white rotter as a result of bavendam test, although more research should be required.

• Journal of the Korean Wood Science and Technology
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• v.42 no.6
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• pp.635-645
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• 2014

The anatomical characteristics of eight major wood species planted in Indonesia were investigated to provide valuable information for their effective utilization. The growth-ring boundaries of Damar and Sumatran pine were indistinct. Resin canal was found in Sumatran pine but it was not observed in Damar. Cupressoid pit and taxodioid pit were found in Damar and window-like pit and pinoid pit were observed in Sumatran pine. Tracheid length of Damar and Sumatran pine was shorter than $3,000{\mu}m$. There were uniseriate rays in Damar and Sumatran pine and fusiform ray in Sumatran pine. All the hardwood species observed in this study were diffuse-porous. They had different vessel groups, i.e., solitary pore in Afrika and Simpur Batu, pore cluster in Angsana and mostly 2-4 rows of radial pore multiple in Mahoni. Mindi and Trembesi had mostly 2-3 rows of radial pore multiple with paratracheal parenchyma as aliform and confluent types. Afrika, Mahoni and Simpur Batu showed heterocellular rays which composed of procumbent cells in the body and mostly 1-2 rows of upright and/or square cells in the margin. All ray cells procumbent was observed in Angsana, Mindi and Trembesi. The large rays commonly exceeding 1 mm in height and ray width of 3~6 cells were observed in Simpur Batu. The other five hardwood species showed ray width of 1~3 cells. Vessel number per $mm^2$ of Angsana and Simpur Batu was higher than those of the other hardwood species. The length of wood fiber and tracheid showed a tendency to increase from pith to bark. By IAWA list, fiber length of hardwoods was classified into long in Simpur Batu and short in Angsana and Trembesi.

• Korean Journal of Soil Science and Fertilizer
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• v.41 no.1
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• pp.1-8
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• 2008

The objectives of this study were to compare nutrient natural input between thinned and unthinned natural hardwood stands at Mt. Joongwang, Pyongchang-gun, Gangwon-do. Throughfall, stemflow, A-layer and B-layer soil water as well as litterfall were sampled at two-week intervals during the period of June to October from 2002 to 2004. The amount of rainfall interception in thinned and unthinned natural hardwood stands was as 12% and 18%, respectively. The results indicated that there was no difference in annual nutrient input by rainfall between thinned and unthinned stands. $Na^+$, $Cl^-$ and $SO_4{^{2-}}$ concentrations of A-layer soil water in the unthinned stand were higher than those in the thinned stand. In the B-layer soil water, $Ca^{2+}$, $Cl^-$, $NO_3{^-}$ and $SO_4{^{2-}}$ concentrations in the unthinned stand were higher than those in thinned stand. Mean annual litterfall input was $2,706kg\;ha^{-1}$ in unthinned stand and $2,589kg\;ha^{-1}$ in thinned stand. Total-N input from litterfall was $50.28kg\;ha^{-1}yr^{-1}$ in the unthinned stand and $36.81kg\;ha^{-1}yr^{-1}$ in the thinned stand, while there was no difference in exchangeable cation input from litterfall between thinned and unthinned stands. Thus, the difference in nutrient inputs except for N by throughfall, stemflow and litterfall between the two stands was not influenced by thinning.

• Journal of Korean Society of Forest Science
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• v.87 no.4
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• pp.631-641
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• 1998

The objectives of this study were 1) to classify the types of Quercus mongolica stands at Mt. Joongwang and compare their quality, and 2) to determine the proper future tree number of Q. mongolica per ha and the appropriate distance between the future trees. The results from this study were as follows : Q. mongolica stands at Mt. Joongwang was classified into four types, pure Q. mongolica stand as stand type I, Q. mongolica - hardwood stand as stand type II, Q. mongolica - Pines densiflora stand as stand type III, Hardwood - Q. mongolica stand as stand type IV, according to mixture rate in stand volume. Stand type IV showed the best quality stem of Q. mongolica among the stand types, and the stem quality of Q. mongolica in Q. mongolica stand mixed with hardwood as stand types II and IV was better than those in pure Q. mongolica stand as stand type I and in Q. mongolica - P. densiflora stand as stand type III. If the management goal for Q. mongolica stand is to produce its high quality-timber, it is desirable to sustain proper mixture rate of Q. mongolica with another hardwoods. The proper number of future trees in pure Q. mongolica stand as stand type I was 122trees/ha and reasonable distance between the future trees was 9.15m. The distance between future trees in other stand types was 7.2m to 9.3m for stand types II and IV, while 8.0m for stand type III. Thus, the classification of Q. mongolica stand type based on stand character and maturity, and proper stem number of future tree and optimum distance between future trees would be a useful forest tending work.

• Journal of the Korean Institute of Landscape Architecture
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• v.40 no.3
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• pp.81-90
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• 2012

Improvements in the quality of life have resulted in a heightened awareness of safety and the environment. As a result, timber as an environmentally friendly material, is used for landscape facilities and a wide range of purposes. But there are a large number of defects since there are twists and cracks that can be found in wooden landscape facilities. This has led to the use of imported hardwood instead of the Western Hemlock which has been in widespread use. Hardwood is expensive. However, it is being used without any information or research on how much it reduces the actual defects. Construction contractors are in great need of information on the characteristics and defect rates of different types of timber. This study investigated and analyzed the cracks in four types of timber - namely the Western Hemlock, Burckella, Nyatoh and Malas - in order to provide basic information to construction contractor for them to be able to select and use the appropriate type of timber. The main results of this study are as follows. First, the Western Hemlock had 1.90 $cracks/m^2$, Malas had 0.83 $cracks/m^2$, Burckella had 0.14 $cracks/m^2$, and the Nyatoh had the least number of surface defects at 0.04 $cracks/m^2$. Second, while Malas has the highest degree of strength timber, Nyatoh had the smallest defect rate. This showed that having high timber strength does not necessarily mean it has less defects. Third, the Western Hemlock was the least expensive and Burckella was the most expensive. However, considering the cost of repairing defects, it would be economically advantageous to use Burckella and Nyatoh which have low defect rates. This study aimed to provide basic information to landscape construction contractors for them to be able to select and use the appropriate type of timber when constructing wooden outdoor rest furniture. The results are expected to contribute to quality enhancements and defect reduction in landscape facilities.

• Journal of Wetlands Research
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• v.17 no.2
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• pp.124-129
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• 2015

In order to get as ecological basic data for river restoration, vegetation investigation was conducted in natural river and analysed it synecological methods, such as ordination cluster. 29 plant communities units were identified and the major dominant plant communites were Quercus mongolica community, Pinus densiflora community, Populus davidiana community, Q. variabilis community and Prunus sargentii community. River vegetations were classified into ravine and gorge forest type and riverine softwood forest type. Ravine and gorge forest was dominanted by hardwood which located in steep slope and in high elevation, and riverine softwood forest by softwood, salix spp. Naturality was an important criterion for the selection of rivers, so many of the selected rivers are located in the upper stream and mid stream rather than the lower stream, where more human intervention is involved. Plant communities were consisted of hardwood forest(44 plots, 92%) and softwood forest(4 plot, 8%), respectively. PCA with total layer data showed 5 groups of communities: Q. mongolica community group, Prunus sargentii community group, Pinus densiflora community group, Prunus sargentii community - Pinus densiflora community group and the rest communities group. PCA with tree layer showed 3 groups: Q. mongolica community group, Prunus sargentii community group, and the rest community group. Cluster analysis also a showed a similar communities group to PCA ordination, but Magnolia sieboldii community and Prunus sargentii community were distinguished from the PCA result. From the result, it can be concluded that the plant communities of riparian be divided into hardwood and softwood forest by statistical techniques. It was appropriate to plant species such as Quercus mongolica, Pinus densiflora, Populus davidiana, Quercus variabilis and Prunus sargentii, at levee zone and high water level. And Sliax spp. were appropriate for planted plants at waterfront and low water level. The herb species to be planted on the floodplain were recommanded in the species composition co-occurred with the woody species.

• 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.

• Korean Journal of Plant Resources
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• v.33 no.4
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• pp.303-310
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• 2020

This study was conducted on propagation use for conservation scheme of a threatened plant; Wikstroemia ganpi (Sieb. et Zucc.) Maxim(Geomundo false ohelo). The seed propagation was showed higher (95%) in storage and lower values in ground and cutting. Softwood cutting was higher than hardwood cutting and it was possessing higher ratio of rooting that increase concentration of IBA and NAA. It was determined that for Geomundo false ohelo seedling was effective than cutting. In-situ and ex-situ conservation and restoration of substitute habitats of Geomundo false ohelo is therefore necessary due to human trampling in the habitats, damage, natural selection, loss and suppression.

• Journal of Korean Society of Forest Science
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• v.95 no.4
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• pp.393-397
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• 2006

Thuja koraiensis Nak. is a short and creeping evergreen shrub which reaches about 3 m in height and only occurs in the northeast China and in high mountains over the Korea. It's designated as a rare and endangered tree species in Korea and DD (data deficient) in Red List Category & Criteria of IUCN. This study was carried out to develop the propagation technique by cutting for conservation of genetic resources of T. koraiensis. The rooting responses of branch cuttings, obtained from hard (May) and semi-hard wood shots (August) to three plant growth regulators (PGRs), namely, IAA, IBA, and NAA applied at various concentrations (0, 100, 500, 1000, 2000, and 3000 mg/l) were examined in sand and mixed soil media. Percentage of rooting showed significant difference between cutting time, among kinds and among concentration of PGRs. The optimum cutting time was April to May in hardwood cutting. The application of IAA 1000 mg/l and NAA 500mg/l were effective in callus formation and rooting of cutting. Relatively, rooting of cutting of the control taken in May was above 93%.