• Journal of the Korean Wood Science and Technology
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• v.23 no.2
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• pp.47-54
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• 1995

This study was to measure the properties of logs and classify them by non-destructive methods. The purpose of this experiment was focused at mensurability of logs by non-destructive methods. The non-destructive instrument, Stress-Wave Timer 239A which was made by Metriguard in U.S.A., was used. The stress wave velocities of log's cross direction were measured and compared with three different methods; 1. with hammer, 2. with hammer and D.B.H. meter, 3. with manufactured instrument. Number of used logs were seven logs, which were classified by naked eye into six groups; very severe rot, severe rot, mild rot & knot, mild rot & check, mild rot, sound log, and in diameter were into three groups; large(57.4cm), medium(36~41.2cm), small(28.9cm) log. The results, which were classified by mensurability with non-destructive methods, were followed; 1. The stress wave velocities were very different between rot and sound log. So it meant the possibility of mensurability of logs by non-destructive method even if high standard error. 2. The stress wave velocities decreased with checks more than with rots, which meant the checks affected speeds more. 3. The stress wave velocities increased with knot. 4. The velocities with manufactured instrument showed lower standard error, so more accurate results than other methods. Especially the required labour decreased from 3~4 to 2 persons. 5. Finally, the mensurability showed more accurate results and made the classification of logs scientific.

• Journal of Plant Biology
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• v.5 no.2
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• pp.13-16
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• 1962

Without annual ring, the bamboo can not measured by ordinary mensuration method. Other methods yet tried failed to prove the reliability. That means, as often pointed out, that the bamboo lumbering (including forest management) is not free from being precarious. Noting the fact, this author performed a serieds of comparative observations on a group of bamboos in different stages of growth in order to find out if there is any surer mensurability. A conclusion has been reached that the external feature of joints of branch has close connection with the age of bamboo, that the joints of the third major branch counting from the ground have, as shown in the first table, the most probability, its mean being 94.3 per cent, and that those in ages of 3 to 5 have the probability of 100 per cent, showing the far greater accuracy as compared with those in older ages. The above conclusion needs to be adjusted with the following findings; 1) When observed disregarding the joint-tongue(the remainder of the preceeding year's sheath), the major branches show no better probability than the minor ones. 54 to 78 per cent of them shows no difference between them. Probability is averaged by 60 per cent. 2) When in spring the old sheaths drop away from the joints, the new ones sprout out in their places and consequently the joints present an appearance of a kind of joint-ring. But since this joint-ring does not always exactly represent the plant age, some other method must be sought after to count the age. This author noticed what is called "joint-tongue" the tongue-like part of triangle shape which remains at the base of the sheath of the fallen leaf. A fact was ascertained that when the number of the joint-ring coincides with that of the remaining joint-tongue, it exactly indicates the age of the plant.the plant.