• The Korean Journal of Ecology
• /
• v.25 no.1
• /
• pp.29-31
• /
• 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.

• Journal of Korean Society of Forest Science
• /
• v.69 no.1
• /
• pp.42-50
• /
• 1985

The vegetation of common Cryptomeria (Cryptomeria japonica D. Don) stands planted in Chonnam- province was investigated to obtain the fundamental informations for evaluation of suitable site and the improvement of managing method of the Cryptomeria stands in this region. The results investigated were summarized as follows; 1) The growth condition of common Cryptomeria planted 21-25-year-old stands was similar that of same species growing in Akidaken-district in Japan, while the growth condition of 51-58-year-old stands was not so good as that of Japanese. 2) Total number of plant species was 256. The number of floristic composition varied in the range of 42-99- species, which should be mere than those of Japanese. 3) The investigated sites were located in temperate southern part and in subtropic northern part of Korean peninsular. The types of understory vegetation were classified from I to IV class. 4) From the results of high max. possible diversity (H' max), and dominance (1-J') and from the low simple dominance (${\lambda}$) and evenness (J'), It could be concluded that vegetation was relatively in evenness. 5) From the low percent similarity, the specificity among the stands could be evaluated as considerable. 6) After the index of Morista, the 8th stand in Chang sung showed the generalized vegetation, while the 12th stand in Chang hung showed the specialized vegetation. 7) From the low values of Sneath-Sokal distance, the similarity among the stands investigated appeared very high.

• Journal of Korean Society of Forest Science
• /
• v.90 no.6
• /
• pp.742-746
• /
• 2001

This study was carried out to develop volume equations for Japanese Res Cedar(Cryptomeria japonica D. Don) trees which were widely planted from 1920s throughout the southern regions in south Korea. The 31 trees for stem analysis were selected in 6 different sites in the southern and 29 trees data were used for developing volume equation. The best equation in estimating Japanese Red Cedar trees's volume was suggested as $V=-0.002908+0.000125D^{1.907114}H^{0.645131}$. The simultaneous F-test for this equation revealed that the estimated individual tree volume was not significantly different (p=0.1936) from the observed tree volume for model evaluation. Therefore, this individual tree volume prediction equation could provide basic information for the construction of yield table and forest management.

• Journal of the Korean Wood Science and Technology
• /
• v.8 no.2
• /
• pp.6-8
• /
• 1980

Japanese larch veneer, Cryptomeria veneer and japanese cypress veneer were peeled with condition of nose bar pressure at 5%, 10%, 15%, to find the optimum nose bar pressure. 1. Optimum nose bar pressure was 15% in 2mm thickness veneer of japanese larch. 2. Optimum nose bar pressure was 5% in 2mm thickness veneer of Cryptomeria. 3. Optimum nose bar pressure was 15% in 2mm thickness veneer of japanese cypress.

• Journal of the Korea Furniture Society
• /
• v.22 no.1
• /
• pp.18-25
• /
• 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.

• Journal of the Korea Furniture Society
• /
• v.11 no.1
• /
• pp.31-36
• /
• 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 Conservation Science
• /
• v.31 no.4
• /
• pp.341-350
• /
• 2015

The preservation has been conducted for wooden ship timber excavated from Bonghwang-Dong, Gimhae, Korea. The species were analyzed for conservation as pre-treatment. Outer panel was analyzed as Cinnamomum spp. and trapezoid wooden material, wooden wedge was Cryptomeria japonica D. Don.. Wooden ship timber have been treated by vacuum-freeze drying after impregnation with aqueous PEG#3,350 solution(almost 45%). The timber of Bonghwang-Dong ship is considered as Japanese ship that many data such as conformation of ship, location of site, japanese artifact of around site were confirmed. In addition, The ship timber give us the important information about the international trade with Japan.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.25 no.2
• /
• pp.71-79
• /
• 2023

The quantification of soil respiration rates is important to understand carbon cycles of forest ecosystems. Soil respiration rates were assessed using Li-8100A soil flux system in one evergreen broadleaved (Quercus glauca Thunb.) and two coniferous (Cryptomeria japonica D. Don and Chamaecyparis obtusa Endl.) stands from May 2020 to April 2022 in southern Korea. Monthly variations of soil respiration rates were higher in the Q. glauca stand than in the C. japonica and the C. obtusa stands. The mean soil respiration rates were significantly higher in the Q. glauca stand (2.63µmol m^-2 s^-1) than in the C. japonica (0.93µmol m^-2 s^-1) and C. obtusa (0.99µmol m^-2 s^-1) stands. The three stands showed exponential relationships between soil respiration rates and soil temperature (R² = 0.44-0.80). The sensitivity of temperature (Q10 values) to soil respiration rates was highest in the Q. glauca stand (5.13), followed by the C. obtusa (3.10) and C. japonica (2.58) stands. These results indicate that soil respiration rates can be increased more in evergreen broadleaved stands than in coniferous stands under enhanced soil temperature.

• Korean Journal of Plant Resources
• /
• v.22 no.6
• /
• pp.535-539
• /
• 2009

The time of seed collection is regarded as one of major concerns to obtain sound seeds. The physical and germinal aspects of Cryptomeria japonica D. Don (Taxodiaceae) seeds were analyzed to determine the optimum harvesting time in Korea. Cones were picked every 10 days from the $30^{th}$ of July to the $30^{th}$ of October in both 2005 and 2006. Seeds were collected from picked cones. Seed size and weight were not significant in two consecutive years. The 1,000-seed weight was 3.3 g for cones picked at the $18^{th}$ of August and 5.3 g for cones picked at the $30^{th}$ of September. The size of seeds was increased as the time of collection from the $18^{th}$ of August to the $30^{th}$ of September: from 19.3 mm to 21.3 mm in length and from 15.8 mm to 18.5 mm in width. Average germination rates in 2005 was 18.3% and 19.6% in 2006. The highest germination rate was 34.3% from seeds collected at the $30^{th}$ of September in 2005. In 2006, the highest germination rate was 31.7% for seeds collected at the same date as the 2005 seeds. After the end of September, germination rate was decreased in both years. The results implied that the best cone picking time for Korean C. japonica seeds is around the end of September.

• The Korean Journal of Ecology
• /
• v.26 no.3
• /
• pp.123-127
• /
• 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.