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  • 1
    Publication Date: 2002-11-05
    Description: Summary The influence of heat and loading time on the mechanical properties of Calamus merrillii Becc. was evaluated by measurement of dynamic Young's modulus and creep compliance at different temperature settings. Young's modulus decreased steadily as temperature was elevated. Creep compliance, on the other hand, increased steadily with loading time, similar to wood. Compliance rates were more or less the same at all temperature settings except for one particular temperature which deviated extremely from the rest. This temperature indirectly represents the softening temperature. Reduction in strength caused by heat was highly influenced by the cellular composition of the stem as well as the sensitivity of its basic chemical constituents, e.g., hemicellulose content, to heat. Knowing this basic behavior of rattan stems will enable manufacturers to design rattan products more efficiently.
    Print ISSN: 0018-3830
    Electronic ISSN: 1437-434X
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Published by De Gruyter
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  • 2
    Publication Date: 2002-08-26
    Description: Summary Growth stress (growth strain) in trees is usually evaluated using either a strain gauge or a dial gauge to measure the strain release. We summarize the techniques used to assess growth stress and compare the two methods. The dial gauge method measures change in distance between two pin targets when growth stress is released by sawing two grooves; from this the strain released is calculated. The absolute values of the strain released depended on whether the two grooves were sawn inside or outside the pin targets: the values in the first case were approximately twice those in the latter. If the grooves were sawn outside the pin targets, the values for the strain released were about the same as with the strain gauge method, in which the strain released by sawing a groove at each end of a strain gauge is measured. The released strain values were consistent when the strain gauge was glued to the outer surface of the secondary xylem after first fully removing the differentiating xylem. To release most of the surface growth stress and maximize released strain values, the optimal distance between the ends of the strain gauge and the grooves cut to release the growth stress was 3 to 5 mm, and the optimal depth of the groove was 5 to 10 mm. Most of the growth stress was released immediately when the grooves were sawn.
    Print ISSN: 0018-3830
    Electronic ISSN: 1437-434X
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
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  • 3
    Publication Date: 2000-10-25
    Description: Summary The tangential strain on the inner bark of Cryptomeria japonica saplings grown in a growth chamber was continuously measured using strain gauges. Compression wood formation was induced by artificial inclination. The diurnal changes in tangential strain during light/dark cycles in the growth chamber differed from those observed in the field. The total strain increased daily, increasing incrementally during dark periods and decreasing in the light, as observed in the field. In the growth chamber, however, steep increases and rapid decreases in strain were found immediately following lights-off and lights-on. In the inclined saplings, the strain increased more on the lower side of the stem than on the upper side; and the increment of the strain in the dark and the decrement in the light were larger on the lower side than on the upper side. The change in tangential strain on the inner bark surface arises from changes in the volume of differentiating cells, corresponding to turgor pressure changes and cell-wall extensibility changes. Therefore, the differentiating tracheids into compression wood appear to expand at night and shrink in the daytime more than the differentiating tracheids into normal wood.
    Print ISSN: 0018-3830
    Electronic ISSN: 1437-434X
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
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  • 4
    Publication Date: 2003-10-30
    Description: Summary This paper describes the effect of light on the diurnal change in the innermost surface of developing secondary walls. Cryptomeria japonica D. Don saplings were grown in two growth chambers, in which temperature and relative humidity were kept constant and the light-dark phase of the photoperiod varied. One chamber reproduced the natural light-dark phase, while the other reversed it. Samples of differentiating xylem were collected during the dark period when the tangential strain, used as an index of volumetric changes in differentiating cells, was high, and during the light period when the tangential strain was low. The innermost surface of developing secondary walls in differentiating tracheids was observed by field emission scanning electron microscopy. In the specimens collected during the dark period, amorphous material was observed and the cell wall surface was immunogold-labeled with an anti-glucomannan antiserum. In the specimens collected during the light period, cellulose microfibrils were clearly evident, and amorphous material and immunogold labeling were rarely observed. These results demonstrate that the diurnal changes in the innermost surface of developing secondary walls correspond to the light-dark cycle over 24 h.
    Print ISSN: 0018-3830
    Electronic ISSN: 1437-434X
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
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  • 5
    Publication Date: 2001-12-14
    Description: Summary In order to clarify the growth stress mechanism of tree species in tropical forest, peripheral and internal longitudinal released strains in 39 year-old teak (Tectona grandis) trees planted in West Java, Indonesia were investigated using the strain-gauge technique. Results showed that both of the peripheral and internal longitudinal released strains were not affected by the rate of growth of the trees. However, released strains distribution inside tree stem, from pith to periphery, were significantly affected by growth rate; slow growing trees generate steeper released strain gradients.
    Print ISSN: 0018-3830
    Electronic ISSN: 1437-434X
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
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  • 6
    Publication Date: 2001-11-06
    Description: Summary The overall silica content in 10 rattan species was analyzed. Its distribution within the stem of Calamus merrillii Becc. was also tested. Anatomical observations were performed to explain the silica content variation. Ash and silica content varied among species. Regardless of diameter class, silica accounts for 44% to 48% of the overall ash content of the stem. Silica in the medium and small diameter stem was twice as much as in the large diameter stem. Within Calamus merrillii Becc., silica was abundant in the epidermal layer. It was responsible for 74% to 85% of the total silica content of the stem, which explains the variation in silica content between diameter classes. The proportion of epidermal layer contained in the sample deviated among the species causing a variation in silica content. Epidermal silica did not vary along the length of the stem while silica in the stem itself varied significantly from base to top. Differences in silica body frequency per vascular bundle caused such deviation.
    Print ISSN: 0018-3830
    Electronic ISSN: 1437-434X
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
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