• Journal of the Korean Wood Science and Technology
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• v.23 no.2
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• pp.32-36
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• 1995

A study was conducted to evaluate the dynamic mechanical properties (modulus of elasticity, resonant frequency and interanal friction) of compression wood in Pinus densiflora. Vibration method was used for estimation of dynamic modulus of elasticity and the values were compared to those of static bending modulus of elasticity. The results obtained are as follows: 1. The dynamic modulus of elasticity of compression wood decreased, whereas that of normal wood increased, with increasing specific gravity. 2. The resonant frequency of compression wood decreased, whereas that of normal wood increased, with increasing specific gravity. 3. The internal friction of compression wood increased with increasing specific gravity. 4. The correlation coefficients between dynamic and static moduli of elasticity in compression and normal woods were high.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2004.05a
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• pp.57-60
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• 2004

Recently. as the alternatives to preserve environment such as effective usage of wastes or unusable resources are drawing attentions, researches and measures for the two tasks, which are reuse of waste wood and development of eco-friendly materials, are being examined and established in various fields. However, they are still insufficient. Therefore, in this study, for the efficient application of waste woods and eco-friendly effects, mortar was produced using sawdust af the waste wood and mineral material cement for combination, in order to produce inorganic boards using waste woods, which were made when sawing. The present study purposed to analyze the physical and dynamic characteristics of woody cement boards, which were made by modifying water-cement ratio for each wood inclusion rate based on a hardening-accelerator inclusion rate set in previous studies and, based on the findings. to provide basic data about the physical properties of inorganic boards made of waste wood, in order to Produce woody cement boards using waste wood, which has problems in being used in the manufacturing of woody cement boards.

• Journal of the Korean Wood Science and Technology
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• v.42 no.6
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• pp.666-674
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• 2014

In this study, we investigated mechanical properties of Korean softwoods after applying thermal compression. Density of compressed woods was notably increased with thermal compression. In case of 50% compression set, density of Korean pine (Pinus koraiensis), Japanese red pine (P. densiflora), and Larch (Larix kaempferi) wood was increased by 71%, 74%, and 76%, respectively, when compared to the control group. The strength of woods was increased and quality of the woods became homogeneous with an increases in the compression set. On the 50% compression set, the compressive strength, bending strength, and hardness of Korean pine wood was increased by 76%, 83%, and 55%, respectively compared to the control group. Longitudinal compressive strengths of Japanese red pine wood increased by 69%, 130%, and 76%, respectively and those of Larch wood increased by 77%, 120%, and 44%, respectively. In thermal compression wood, mechanical properties of Larch wood was the highest, while those of Korean pine wood were the lowest. However, Japanese red pine wood showed the highest in the increase rate of mechanical properties after the thermal compression.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.44 no.5
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• pp.63-71
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• 2012

This study was carried out to investigate pulping properties of the forest biomass arising from the national forest management operation. The forest biomass was collected and classified into many groups according to their species and age. After the chips were made from the forest biomass, the measurement of chip size and chemical analysis were performed. To make the pulps from the forest biomass, the kraft pulping was applied and thereafter the physical and optical properties of kraft pulps were measured. The pulp fibers from the forest biomass had the similar mean fiber length, but their properties became different according to wood species and ages. Differently from the other species, kraft pulps from chestnut wood had the highest kappa number. Acacia, paulownia and chestnut woods made kraft pulps with lower tensile strength and brightness than the others. It could be concluded that acacia, paulownia and chestnut woods must be screened out in order to make a good quality of kraft pulps while being collected during Forest Management Operation.

• Journal of the Korea Furniture Society
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• v.21 no.1
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• pp.72-82
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• 2010

The objective of this study is to identify the species of 17 wooden Buddhist statues of the late Joseon Dynasty (the 17th and 18th century) in Jeollado, southwestern region of Korea. The bodies of statues were made of Ginkgo (Gingko biloba L.: 88%) and alder (Alnus spp.: 12%). The hands of statues were alder(64%), willow (Salix spp.: 27%) and Ginkgo(9%). The bottoms of hollow bodies were covered all with Japanese red-pine (Pinus densiflora S. et Z., 'sonamu') panels. The main species of statue body, Ginkgo tree was known to be introduced to Korea from China with Buddhism. The results indicated that Ginkgo trees of Korea in the 17th century had already become large and rich enough to be used for most of statues. Ginkgo wood has low shrinkage and even texture, which are crucial for carving sculptures. Alder and willow woods used for statue hands have fine and firm textures. The pedestals for these statues were also made of red pine wood. Red pine woods have rather high shrinkage and low hardness, but it is versatile woods strong enough to support heavy statues.

• Journal of the Korean Wood Science and Technology
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• v.10 no.3
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• pp.168-179
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• 1982

The first step to utilize the growing resources of Italian poplar (Populus euramericana I-476) for pulp-Woods, its characteristics and adaptabilities to the pulp industry must be investigated completely. The plantation methods are important for its fast growing in stock, and no less important is the cutting age for its utilization as pulpwood. In this paper, the stone groundwood pulping, refiner groundwood pulping and chemi-groundwood pulping characteristics by the age of tree, along with their physical and chemical characterstics were tested, and relationships between the age groups were analyzed to find out the optimum felling age. The results obtained are as follows: 1. The coefficient of pliability was a little higher in the case of younger trees. 2. The water retention value of each pulp was directly proportional to its physical strength, but this tendency was not detected between the age groups of sample woods. 3. Generally, the physical strength of younger wood pulp was lower regardless of the pulping process. But in the case of pretreatment with NaOH, Asphund and CGP pulp from 5 year old sample wood were stronger in physical strengths than those of GP and Asplund pulp with no pretreatment from 10 years old sample wood. 4. The tear factor of Asplund pulp with alkali pretreatment was higher than that of CGP pulp but the breaking length and the burst factor was similar in all processes. Considering the pulp yield and its brightness, CGP process seems to be advantageous. 5. The dissimilarity of physical strength between 7 and 10 years old wood pulp was not very large in all pulping processes but the physical strength of 5 year old wood pulp was very weak. In the of groundwood pulping from Italian poplar woods, 5 year old wood pulp should be mixed with other long fiber pulp for making a good paper.

• Nuclear Engineering and Technology
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• v.5 no.1
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• pp.3-12
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• 1973

Some physical and chemical properties of wood-plastic combinations(W.P.C.) made of domestic soft woods such as pinus densiflora, pinus rigida and poplus deltoides were measured. The rates of improvement in properties were roughly proportional to the contents of polymer or polymer mixtures in W.P.C. For the W.P.C. obtained by means radiation curing and containing 80% of polymer or polymer mixture, the hardness and water absorptirity were improved 2.2 times and 4 times those of the original wood, respectively. The improvement of hardness was especially remarkable in the W.P.C. made of pinus densiflora and polystyrene(120%) to show 7 times increased hardness. For the W.P.C. obtained by means of thermal curing and containing 80% of polymer or polymer mixture, the hardness and water absorptivity were improved 2.4 times and 3.4 times those of the non-treated woods, respectively. These data indicate that the properties of W.P.C. prepared by means of radiation curing are not much different from those of W. p. C. prepared by means of thermal curing. Both of acid resistancy and alkali resistancy of the W.P.C. were also improved remarkably in comparison with the non-treated wood.

• Journal of the Korean Wood Science and Technology
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• v.27 no.3
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• pp.7-16
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• 1999

This research was carried out to compare structure, equilibrium moisture content(EMC), adsorption and acoustical properties between 4 retention levels of saligenin(o-hydroxybenzyl alcohol) treated, heat-treated and untreated chestnut(Castanea crenata S. et Z.) and paulownia(Paulownia spp.) woods. The cell structures of untreated wood and heat-treated wood were not different but the cell wall of saligenin treated wood was thicker than that of untreated wood for both species. EMC of untreated wood was the highest, next was that of heat-treated wood, and that of saligenin treated wood was the lowest, and among saligenin treated woods, EMC was decreased as retention level increased for both species. Adsorption curves were parabolically increased. Acoustical properties of saligenin treated wood were most improved, and the next were those of heat-treated wood. Comprehensive acoustical property was improved at retention level 20% and 30% for chestnut wood, and at retention level 80% for paulownia wood.

• Journal of the Korean Wood Science and Technology
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• v.43 no.1
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• pp.1-8
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• 2015

Relationship between annual ring width and physical properties of 24-year old alder woods (Alnus glutinosa L.) that had different seed origins from four provenances such as Bulgary, Italy, United Kindom, and Yugoslavia was investigated. No difference among different origins of seeds was found for the moisture content, density, and shrinkage or tangential radial (T/R) ratio. These properties had also no relationship with the growth rate. As important parameters among wood quality indices, no difference in the density or shrinkage on wood that has different growth rates was detected among alder woods from four different origins of seeds. Therefore, it is considered that higher growth rate might be a key factor for selecting the seed origin of the alder tree.

• Journal of the Korean Institute of Landscape Architecture
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• v.18 no.3 s.39
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• pp.71-84
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• 1990

This study was executed to investigate matters connected with planting of Gapho Citizen's Woods(Park), and to offer the data about countermeasure. The study was executed in 1988 and 1989. The contents of the study were the condition of plants, the environmental factors, the states of tree planting and the user's behavior. The result of this study can be summarized as follows. 1. Because of incongruity of soil and regardless of physiological properties of trees, the plants were damaged by their environment. In particular, the stress of soil moisture was serious. 2. The unsuitable planting forms for the park were found out through the park, which was the result of imprudent, additional planting. And so in planting trees additionally, the participation of landscape architect is needed. 3. There is a serious noisy problem from express way. Because when they planted trees, they did not consider about noise. It affected the quality and utilization of the park.