• The Korean Journal of Ecology
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• 제25권1호
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• pp.29-31
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• 2002

The purpose of this study is to estimate height growth patterns and site index cuties (base index age 50 years) for Japanese red cedar trees(Cryptomeria japonica D. Don) grown in southern regions of Korea. The Chapman-Richards growth function was selected for stand height prediction using on the results of stem analysis data sets. Anamorphic base age invariant site index cuties were presented based on this height prediction equation. The resulting site index prediction equation can provide an indication of the productivity of the site quality based on Japanese red cedar trees plantation ages planted in southern regions of Korea.

• 한국가구학회지
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• 제22권1호
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• pp.18-25
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• 2011

This experiment was carried out to investigate the effects of nail diameter, driving distance from end on the nail check length, and the effects of nail diameter, prehole for nail driving, and nail driving slope on the nail withdrawal resistance, by the static test of universal testing machine. The test specimen were Japanese cedar (Cryptomeria japonica D. Don.) boards grown in southern district of Korea, and the nails for test were 2.02～4.82 mm in diameter. After nail driving, the back face checks of test boards were longer than the surface checks. The optimum nail diameter without checks or loss of nail withdrawal resistance were below 10% of board width and the optimum driving distance from end of boards were ten multiple of nail diameter. The relation between nail diameter (x) and withdrawal resistance (y) was linear and the regression formulae for Japanese cedar board was y = 8.66x + 7.6 ($R^2=0.978$). As both of the prehole diameter and driving slope were increased, the withdrawal resistances were significantly decreased.

• 한국가구학회지
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• 제21권6호
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• pp.479-485
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• 2010

제주도 산지림 및 방풍림 삼나무 목재의 조직 특성, 생재함수율, 무기 함유물 농도 및 흑심재 발생률 조사를 통해 얻어진 결과는 다음과 같았다. 1. 흑심재의 발생률은 산지림의 나무에 비해 방풍림의 것에서 훨씬 더 높게 나타났다. 2. 생재함수율은 심재의 재색이 적갈색에서 흑색으로 변함에 따라 높아지는 것으로 드러났다. 3. 흑심재의 방사조직 내에 존재하는 무기 함유물인 $K_2O$와 CaO는 흑심재의 주요 형성 원인 가운데 하나인 것으로 여겨졌다. 4. 목재의 비중 및 기계적 성질은 제주도의 삼나무가 한반도 남부 지역의 삼나무에 비해 비교적 낮게 나타났지만 제주도 내의 방풍림과 산지림 나무 사이에서는 큰 차이를 보이지 않았다.

• 한국산림과학회지
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• 제90권6호
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• pp.742-746
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• 2001

본 연구의 목적은 1920년대부터 우리나라 남부지방에 대단위로 조림된 삼나무(Cryptomeria japonica D. Don)조림지를 대상으로 하여 최적의 간재적추정식을 개발코자 하였다. 남부지방의 대표적인 삼나무조림지인 6개 지역을 조사하였으며, 이들 지역에서 대표적인 31개의 표준목을 선발하여 수간석해를 실시하였다. 이 중 이용 가능한 29개체목에 대한 수간석해 자료를 이용하여 개발한 최적의 삼나무 재적추정식은 $V=-0.002908+0.000125D^{1.907114}H^{0.645131}$이 제시되었다. 이 식을 이용하여 간재적 실측치와 추정치를 사용한 동시 F-검정(절편=0와 기울기=1)을 실시한 결과, 통계적으로 유의성을 나타내지 않았다(p=0.1936). 따라서 본 연구에서 제시된 간재적 추정식은 남부지방에 조림된 삼나무의 입목 간재적표조제와 경영에 필요한 기초적 자료를 제공해 줄 것으로 판단된다.

• Asian Journal of Atmospheric Environment
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• 제7권4호
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• pp.191-198
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• 2013

Cryptomeria japonica pollen is the most common pollen, which are scattering during each spring season in Japan. Japanese cedar (Cryptomeria japonica) pollinosis is one of seasonal allergic rhinitis that mainly occurs in Japan. In addition, long range transportation of Yellow Sand from the East Asian continent was also found during the pollen scattering seasons in Japan. Therefore, the interaction or impact between pollen and Yellow Sand should be concerned. In this study, our objective was to investigate the airborne behaviour of Cryptomeria japonica pollen grains and its size-segregated allergenic (Cry j 1) particles as the airborne tracer of Cryptomeria japonica pollen during the Yellow Sand events. Airborne Cryptomeria japonica pollen grains and its size-segregated allergenic particles were collected at roadside of urban residential zones of Saitama city during the pollination periods from February to March in two year investigation of 2009 and 2010. The overlap of Yellow Sand events and dispersal peak of pollen grains was observed. According to the Meteorological data, we found that the peaks of airborne pollen grains appeared under higher wind speed and temperature than the previous day. It was thought that Yellow Sand events and airborne pollen counts were related to wind speed. From the investigation of the airborne behavior of the size-segregated allergen particles by determining Cry j 1 with Surface Plasmon Resonance (SPR), the higher concentrations of the allergenic Cry j 1 were detected in particle size equal to or less than $1.1{\mu}m$($PM_{1.1}$) than other particle sizes during Yellow Sand events, especially in the rainy day. We conclude that rainwater trapping Yellow Sand is one of the important factors that affect the release of allergenic pollen species of Cry j 1. Therefore, it is very important to clarify the relationships between Cryptomeria japonica pollen allergenic species and chemical contents of the Yellow Sand particles in further studies.

• 한국가구학회지
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• 제16권1호
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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 $y=-9.6x+85.2(R^2=0.95)$.

• Journal of the Korean Wood Science and Technology
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• 제45권6호
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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.

• The Korean Journal of Ecology
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• 제26권3호
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• pp.123-127
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• 2003

Cubic-meter volumes estimated from two proxy taper functions were compared to observed volumes of Japanese red cedar trees (Cryptomeria japonica D. Don) to evaluate accuracy and precision in the centroid method. Centroid volume estimates were also compared to volume estimates from existing whole-tree volume equations developed for another geographic region. This study found that one proxy function produced unbiased volume estimates while the other was biased. Volume estimates from the whole-tree equations were also biased. However, the volume estimates from the whole-tree equations were more precise than those from the centroid method. These results support previous studies that the centroid method can produce reliable volumes of trees when no other reliable volume equations exist.

• Journal of the Korean Wood Science and Technology
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• 제41권2호
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• pp.141-148
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• 2013

The goal of this study was to find the optimum lamina size from red pine (Pinus densiflora) and Japanese cedar (Cryptomeria japonica) logs for the cross laminated timber (CLT) production. From visual inspection of the logs from two species, red pine log showed a larger knot and warp compared to the Japanese cedar. Different cross-sectional sizes of lamina ($110mm{\times}30mm$, $110mm{\times}40mm$, $110mm{\times}50mm$, $50mm{\times}30mm$, $30mm{\times}30mm$) from two species were analyzed for yield and grade. Regardless of the species, the optimized cross sectional size for maximizing the yield was $110mm{\times}30mm$. In grading for the different size laminas from Japanese cedar and red pine, a higher percentage of the first and second grade was found from the $110mm{\times}30mm$ lamina cut.

• The Korean Journal of Ecology
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• 제27권4호
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• pp.217-224
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• 2004

The purpose of this study is to clarify the effects of the conversion of the forest management type from a natural deciduous broad-leaved forest to an artificial evergreen coniferous forest based on organic matter dynamics. We investigated the amounts and carbon contents of the forest floor and the litterfall, soil chemical characteristics and cellulose decomposition rates in the natural deciduous broad-leaved forest and adjacent artificial evergreen coniferous forest. In the artificial evergreen coniferous forest were planted Japanese cypress (Chamaecyparis obtusa) on the upper slope and Japanese cedar (Cryptomeria japonica) on the lower slope. The soil carbon and nitrogen contents, CEC and microbial activity had decreased due to the conversion of the forest management type from a natural deciduous broad-leaved forest to an artificial Japanese cypress forest, and were almost the same for the conversion to a Japanese cedar forest. Under the same conditions, it is considered that the soil fertility was different by planting specific tree species because the organic matter dynamics were changed by them.