• Journal of the Korean Society of Combustion
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• v.22 no.2
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• pp.9-18
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• 2017

In this study, we measured that fire characteristics of four wood species using indoor finish materials. Wooden specimens were treated with fire retardant chemicals such as diammonium phosphate and potassium carbonate. The wooden specimens are Larix kaempferi, Pinus koraiensis, Cryptomeria japonica, and Chamaecyparis obtusa, which are used for indoor finish. The heat release rate (HRR) values of fire retardant treated woods were confirmed lower than that of untreated woods. For specific details, the HRR values of vacuum impregnated specimens for Pinus koraiensis and Cryptomeria japonica were measured lower than coatings. However, those of Larix kaempferi and Chamaecyparis obtusa showed the opposite effect to it. Total heat release rate values of all wooden specimens, vacuum impregnated were lower than coated specimens.

• Journal of the Korea Furniture Society
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• v.16 no.1
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• pp.1-8
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• 2005

This experiment was carried out to investigate the gluing characteristics of poly vinyl acetate emulsion adhesive(PVAc) on the Cryptomeria japonica laminated boards. This sample trees are major planting species and have been planted in southern district for a long time. The optimum gluing conditions for laminated board were summarized as follows; the amount of spreading glue, assembly time, clamping pressure, and clamping time for PVAc resin were $200g/m^2$, 10min., $5kg/cm^2$, and 6hrs., respectively, and the relative formulae between extension ratio(x) and block shear strength(y) was $y=-9.6x+85.2(R^2=0.95)$.

• Current Research on Agriculture and Life Sciences
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• v.9
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• pp.109-114
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• 1991

The depth and spread of root systems and the density of root branching affect the success and survival of plants subjected to drought. The type and size of root systems are controlled by heredity and soil conditions. There are also important interaction between roots and shoots; roots are dependent on shoots for carbohydrates, growth regulators, and certain vitamins, and shoots are dependent on roots for water, minerals, and certain growth regulators. Pinus thunbergii Parlatore had most of roots in the top 20cm of soil, and had little short of roots in the less than 80cm of soil. Average of root density was $270cm/cm^3$ in the upper soil(0~20cm). Root density of Pinus thunbergii Parlatore was similar to that of Cryptomeria japonica. There is no saying that Pinus thunbergii Parlatore has an advantage over Cryptomeria japonica in the drought. This data will be used to the root density values in the simulation model of black pine stands.

• The Korean Journal of Mycology
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• v.17 no.1
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• pp.14-20
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• 1989

The presence of endomycorrhizal fungi was examined on the soils collected from the followings; Cryptomeria japonica dominant forest (Wan San Park, Jun Ju city) and two coast areas (Digitaria sanginalis dominant; Sin Chang Ri, Young Il Kun and Pragmited communis dominant; Sap Kyo Cheon, A San). Six species in Endogonales were identified; Glomus intraradices, G. occulum, G. clarum, Acaulospora bireticulata, Scutellospora aurigloba, and Sc. gilmorei.

• Journal of Forest and Environmental Science
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• v.24 no.3
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• pp.137-142
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• 2008

In this paper, we apply a logistic regression model to the data of snow damage on sugi (Cryptomeria japonica) occurred in Toyama prefecture (in Japan) in 2004 for estimating the risk probability. In order to specify the factors effecting snow damage, we apply a model selection procedure determining optimal subset of explanatory variables. In this process we consider the following 3 information criteria, 1) Akaike's information criterion, 2) Baysian information criterion, 3) Bias-corrected Akaike's information criterion. For the selected variables, we give a proper interpretation from the viewpoint of natural disaster.

• Journal of the Korea Furniture Society
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• v.11 no.1
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• pp.31-36
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• 2000

Woodceramics are new porous carbon materials obtained by carbonization of wood or woody materials impregnated with thermosetting resin in a vacuum furnace. This study examined the electrical properties of woodceramics made from thinned logs of Cryptomeria japonica as a use for electric articles. The summarized results were as follows: 1. The volume resistivity of woodceramics decreased with increasing density of woodceramics made from 3 type board. And the volume resistivity of woodceramics made from non- steamed board was somewhat higher than steamed board. 2. The consumption of electric power of woodceramics decreased with increasing density of woodceramics and resin contents made from 3 type board. And the consumption of electric power of woodceramics made from non-steamed board was somewhat higher than steamed board. 3. When the woodceramics were coated by silicon, the consumption of electric power increased about 7%.

• Journal of Environmental Science International
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• v.19 no.5
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• pp.627-637
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• 2010

Emission rate of monoterpene and isoprene was measured in five commonly growing tree species of conifers(Pinus thunbergii, Abies koreana, Cryptomeria japonica, Pinus densiflora, Chamaecyparis obtusa) at the Halla mountain sites. Dynamic flow enclosure technique was used and gas samples were collected into Tenax tube. The highest and lowest hourly emission rate was observed in Abies koreana (1.86 ${\mu}g$/gdw/hr) and Chamaecyparis obtusa (0.52 ${\mu}g$/gdw/hr), respectively. The major species of monoterpene from pine trees were ${\alpha}$-pinene, ${\beta}$-pinene, ${\beta}$-phellandrene, myrcene. Particularly, d-limonene was abundant in Abies koreana but ${\alpha}$-pinene, $d^3$-carene and sabinene was in Cryptomeria japonica. Emission rates of isoprene show less significant than those of monoterpene. And also seasonal emission rates of monoterpene were dependent on environmental factors such as temperature.

• The Korean Journal of Ecology
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• v.27 no.1
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• pp.27-33
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• 2004

Cryptomeria japonica plantation was monitored every year during 15 years from 1983 to 1997 for stem diameter and volume. The reciprocal equation, 1/Y = A + B/N, was applied to the relationship between cumulative volume Y and cumulative number N from the largest tree in the stand each year. The parameters A and B, which means respectively the reciprocal of an asymptotic value of total stand stem volume and the reciprocal of the maximum stem volume, are related by a power function. The power functional relationship between A and B derived a linear relationship of B-points ( $N_{B}$, $V_{B}$; $N_{B}$ = B/A, $Y_{B}$ = 1/2A) of each Y-N curve on log-log coordinates. The gradient of B-point line was so steep that the Y-N curve moved parallel upward year by year. The time trajectory of mean stem volume (W) and density ($\rho$) provided evidence in favor of the 3/2 power law of self-thinning, because the gradient of W - $\rho$ trajectory on log-log coordinates approximated to -3/2 at the final stage of stand development. On the basis of the results of Y-N curves and W - $\rho$ trajectory, the time trajectory of maximum stem volume $W_{max obs}$ and $\rho$ was derived theoretically. The gradient of $W_{max obs}$ - $\rho$ trajectory on log-log coordinates is calculated to be -0.6105 at the final stage. The gradient of $W_{max obs}$ - $\rho$ trajectory was steeper than that of W - $\rho$ trajectory at the early stage, while the former is gentler than the latter at the later stage.stage.e.age.e.

• Journal of the Korea Furniture Society
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• v.21 no.6
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• pp.479-485
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• 2010

The anatomical characteristics, green moisture content, inorganic element concentration, and black heartwood percentage were compared between the Japanese cedar (Cryptomeria japonica) planted in a general mountain forest and in a windbreak forest for a mandarin orange field in Jeju island. The results obtained were as follows: 1. Black heartwood percentage was found to be much higher in the trees of windbreak forest than in those of general mountain forest. 2. Green moisture content of wood appeared to increase with the color change of heartwood from reddish brown to black. 3. Inorganic elements of $K_2O$ and CaO in the ray cells of black heartwood were thought to be one of the important factors for black heartwood formation. 4. Wood specific gravity and strength properties were comparatively lower in the trees of Jeju island than in those of southern part of the Korean peninsula. These properties, however, were found to be not significantly different between the trees of windbreak forest and general mountain forest in Jeju island.

• Journal of the Korean Wood Science and Technology
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• v.45 no.6
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• pp.753-761
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• 2017

The heartwood (HW) of Japanese cedar (Cryptomeria japonica) has usually a reddish color. But some trees have black-colored heartwood (BHW). BHW of Japanese cedar has a low commercial value because of the appearance. Therefore, in this study, a comparative analysis was conducted to evaluate the differences in the physical, mechanical, and inorganic element properties, and decay resistance of red-colored heartwood tree (RHW) and BHW. The physical properties showed significant difference between sapwood (SW) and HW, but there was no significant difference between RHW and BHW. From the results of mechanical properties, no significant difference was recognized in SW of RHW, HW of RHW, SW of BHW, and HW of BHW. There were decay resistance differences between RHW and BHW in HW, and between HW and SW in both RHW and BHW, respectively. The magnesium (Mg), potassium (K), and calcium (Ca) contents had significant differences between SW and HW in both RHW and BHW. In this present study, the decay resistances and the contents of Mg and K were higher in HW than in SW both for RHW and BHW, while these measurements were lower in RHW than in BHW. Therefore, BHW was considered to be worthy as a high-quality material as RHW.