• Journal of Forest and Environmental Science
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• v.14 no.1
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• pp.1-13
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• 1998

In this paper, it has been discussed on the relation between the anatomical features of woods and the penetration of methyl methacrylate monomer system into major Korean tree species, especially the Pinus koraiensis, Larix leptolepis, Quercus mongolica and Tilia amurensis. 1. There was some differences in penetration of polymers among different tree species, but generally the penetration of ring porous woods seems to be larger than that of diffuse porous woods and it was very difficult to penetrate to Larix leptolepis, especially to the that of heart wood. 2. The penetration on transeverse surface was relatively easy but radial and tangential impregnation were somewhat hard and differences between them were negligible. 3. The penetration of sapwood was larger than that of heartwood and its differences varied according to the existence of tyloses or contents in vessel. 4. Generally the polymer penetration of earlywood was larger than that of latewood in ring porous woods, but on the contrary, penetration of earlywood was small than that of latewood on diffuse porous woods. 5. Vessel diameter of wood had nearly no relation to polymers penetration. This seems to come from the reason that effective vessel diameter varies with the existence of tyloses or contents in vessel. 6. The penetration of ray tracheids was larger than that of ray parenchyma cells in softwoods, but penetration of hardwood rays seems to be small in comparison with softwood ray parenchyma cells. 7. Specific gravity and annual ring width had no relation to the penetration of polymer.

• The Korean Journal of Malacology
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• v.19 no.2
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• pp.125-132
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• 2003

Age and growth of the the Jedo venus clam, Protothaca jedoensis were investigated using samples from the subtidal zone of Boryeong, Chungcheongnam- do, Korea from January to December, 1999. The relationship between shell height and ring radius in each group was expressed as a regression line. Therefore, it could be recognized that there is a correspondence in the formation of each ring. Based on the monthly variation of the marginal index of the shell, it was suggested that the annual ring mark formation occurred during the period of February to March once a year. The relationship between shell height (SH) and total weight (TW) was represented by the non-linear equation: TW = 0.0007 SH$^{2.8919}$, and also in the relationship between shell length (SL) and shell height (SH), shell height (SH) and shell width (SW) were represented by the linear equations: SL=1.1067SH+1.778, SW=0.6758SH-0.9824. Growth curves for shell height and total weight fitted to the von Bertalanffy equation were expressed as: SH$_t$ = 81.546(1-e$^{-0.176(t+0.381)}$), TW$_t$ = 227.65(1-e$^{-0.176(t+0.381)})^{2.8919}$.

• Journal of the Korean Wood Science and Technology
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• v.15 no.3
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• pp.1-13
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• 1987

This study was carried out to investigate the variations of dimension and exterior shape of vessel elements, morphology of spiral thickening and ray-vessel pit in korean diffuse-porous woods (56 species, 18 families), The tangential pore diameter and vessel element length was increased, whereas the pore number per unit area($1mm^2$) was decreased from pith outwards. The tangential pore diameter was decreased but the length of vessel element was not changed from earlywood to latewood within an annual ring. However, the dimensional variations of vessel element was not able to be recognized among relative positions in peripheral variation. The exterior shape of vessel element could be classified into four types; Type 1 is without tail, Type 2 with ligulate tail, Type 3 with broad taper tail and Type 4 with the very short length between perforations. The distribution frequency of Type 2 and 3 was relatively high in comparision with the others. According to the prominence, distribution position and branched shape, the spiral thickenings could be divided into five types. The spiral thickenings occurred 52% in the species observed. Thus it was doubtful to consider the simple presence of spiral thickening as diagnostic index in diffuse-porous woods. The morphology of ray-vessel pit could be grouped as reticulate, scalariform, oval, linear and coalescent type. Most of species examined showed oval and linear type.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.48 no.5
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• pp.760-767
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• 2015

First annulus formation and age determination of otoliths were examined for chub mackerel Scomber japonicus collected in Korean waters over the one year from January to December in 2009. Translucent zone was regarded as an annual mark. Age interpretation criteria was based on the data of the number of translucent zone, capture date, and edge type of the otolith, assuming the nominal birthday to be 1 January. Monthly changes in mean marginal index indicated that translucent zone was formed once a year, mainly in June. The otolith of 0-ring group was detected comparing the progression by month of the smaller fish length, appearing to be a single first opaque zone. The average distance from the core to the first translucent zone was ~1.77 mm, provided as supplementary information to increase ageing accuracy. The ageing criteria for chub mackerel was made to determine correct year-class with the purpose of effective stock assessment. This method using nominal birthdate and edge type analysis could estimate age of fish closer to the true age than purely counting the number of translucent zone on a whole otolith.

• The Korean Journal of Malacology
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• v.24 no.3
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• pp.189-197
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• 2008

In order to develop the sustainable ecological management, short-necked clams, Ruditapes philippinarum, were collected from Yoengi coast in Tongyoeng, Korea. The growth of the clam was estimated as: $L_f=68.08{\cdot}(1-e^{-0.145(t+0.324)})$ from ring radius composition of shell. Instantaneous co-efficiency of total mortality and natural mortality were calculated as: 0.991/year and 0.494/year, respectively. The age of the clams from the first capture was estimated to be 3.28. The total biomass was estimated to be 212 MT in the fisheries area (6.4 ha). Applied by these parameters, the annual recruit biomass and the current yield per recruit were calculated to be 649.5 individual/$m^2$ and $0.7\;g/m^2$, respectively. The current fishing intensity was much lower for maximum sustainable yield and acceptable biological catch. Although higher yield per recruit could be achieved by increasing fishing intensity, it is favorable to retain the current fishing intensity because of the unique fishing attitude on Yeongi coast in Tongyoeng, Korea.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.49 no.3
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• pp.261-269
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• 2013

The age and growth of the Pacific cod, Gadus macrocephalus were investigated using left sagittal otoliths of 682 individuals collected in the West Sea of Korea from January to December 2007. The seasonal changes in the ratio of an opaque zone to interval between annular rings revealed that the narrow translucent parts of the otolith were annual growth rings formed between February and March once a year. The spawning period was December to January and therefore the duration from fertilization to the complete formation of the opaque zone became thirteen months. From the parameters calculated using the average length when the year ring was formed, the estimated von Bertalanffy growth equations were $L_t=100.0(1-e^{-0.1640(t+0.5247)})$ for females and $L_t=64.6(1-e^{-0.3335 (t+0.3342)})$ for males when is total length in age t.

• The Korean Journal of Ecology
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• v.6 no.3
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• pp.198-207
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• 1983

The dry-matter production, the litter decomposition and the nutrient cycle were studied on Quercus serrata and Carpinus laxiflora forests at Piagol in Mt. Jiri. With the growth curves of the annual ring, the time schedules for the maximum productivities and maximum yields were measured. In Q.serrata forest, the maximum productivity was 11.36 tons $ha^-1 yr^-1$ at the 49th year and the maximum yield was 115.78 tons $ ha^-1$ at the 73th year, and in C. laxiflora 7.24 tons $ha^-1 yr^-1$at the 35th year and 82.5 tons $$ha^-1 $$at the 53th year, respectively. The maximum productivities and the maximum yields of the leaves, stems and roots of the trees were calculated. The contents of nitrogen, phosphorus, potassium and organic carbon were measured.. While inorganic materials were the most abundant in the leaves, organic materials in stems. The maximumproductivities and the maximum yields of the constituents of the trees were calculated, assuming that the constituents of the trees increase allometrically. The decomposition rates were as follows: k = 0.301 for Q.serrata forest, and k = 0.364 for C. laxiflora forest. The litter of the former was decayed more slowly than that of the latter. The halftimes for decomposition were 3.2 and 1.9 years, respectively.

• Journal of the Korean Wood Science and Technology
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• v.38 no.6
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• pp.463-469
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• 2010

To suggest the practical use of fast growing tree, we estimated the physical and sound absorption properties of Cherospondias axillaris which is one of the japanese fast growing species. The average annual ring width and air dry specific gravity were 8 mm and 0.55 respectively. The sound absorption coefficients of Cherospondias axillaris wood generally seemed to be a little higher than those of other construction materials such as 6 mm thick gypsum board and 18 mm thick fiberboard, and considered that it could be used as a constructing material owing to relatively good mechanical properties and sound absorption properties.

• Journal of the Korea Furniture Society
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• v.12 no.1
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• pp.47-55
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• 2001

Violin bridge blank cut from maple wood with good quality has typical pattern of the radial direction in the side edge with minimal dispersion. This experimental study was designed and carried out to examine the effect of the physical and macroscopical characteristics on the compressive creep of violin bridge blank which had been imported from European manufacturer. This research arose from the idea that the maple solid wood with heterogeneous wood density and ray direction in the side edge would have uneven rheological property of violin bridge blank which is supposed to be pressed by the tension of strings. Experimentally, the compressive creep of bridge blank became smaller with the higher density of imported maple wood and showed clear density-dependence for the duration of load under the string tension of 5 kgf. Every bridge blank showed the behavior of primary creep stage(stress stabilization) having logarithmic regression creep curve with high correlation coefficient under the designed stress level. Even though the relationship between compressive creep and ray direction on the side edge of bridge was not so clear contrary to expectation, we could conclude that wood density and ray direction should be the quality decisive factors affecting the acoustical characteristics and performance of the bridge, the core member of violin-family bow instruments.

• Journal of the Korean Wood Science and Technology
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• v.11 no.1
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• pp.5-11
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• 1983

This paper aims at gaining the informations atout the fibril angle at secondary walls of tracheids. The test specimens were taken from disks on stem wood of "Pinus koraiensis Sieb. et zucc". The method of measuring the fibirl angle was selected so-called "iodine method" that crystalline aggregates of iodine may be induced to form within the elongated interstices of the cellulose matrix of the secondary wall and that these elongated crystals are oriented parallel to the long axies of the fibrills of cellulose. The following conclusions may be drawn from the results of this investigation. 1) Gross average fibril angle was about $17.6^{\circ}$ on stem wood. 2) Its values seem to be greater for earlywood (avg.$19.8^{\circ}$) than for latewood tracheids (avg.$15.3^{\circ}$) in normal wood. 3) According to the increase of annual ring from pith to barks the orientation of fibril angle seems to be decrease gradually in normal wood. 4) In the case of height variation in trees the sample trees have a tendency to increase the orientation fibril angle to the increase of tree height in stem.