Seeds of Paulownia tomentosa cannot germi-nate without light. As is shown in Table 1, very few of seeds germinated when kept in darkness, while they showed good germination in diffused light. Ten minutes breakage of dark treatment did not show any effect. The experiment was carried on in glass incubator kept at 25°C. For each plot were supplied 4 Petri dishes containing 50 sterilized seeds, and 1% agar was used as germinating bed.

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One of the characteristics in Japanese charcoal-making is the so-called “ref ining”-a high tempera-ture treatment after the carbonization has almost finished.
The writers made a study on the relationship between the properties of several kinds of Japa-nese charcoal and different intensities of ref in-ing. The study revealed that in the case of white charcoal the refining has proceeded sa.f fi-ciently and homogeneously, while in the case of black charcoal it was insufficient and partial.
The study also revealed their physical and chemical properties as follows:

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he propagation of Cryptomeria japonica D. Don by small green shoot cuttings was examined in order to obtain a great quantity of clonal materials rapidly from a mother stock. The cuttings, about 5 cm long were collected from 10 year-old stock plant. They were treated with potassium β-indoleacetate in concentration of 0.04, 0.12, 0.20 percent and water control and Kanumatsti was used as rooting media. The treatment of the growth substance was effective to shorten the period and to enlarg the final amount of rooting in this experiment.

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1. The log-making production rate (felling, trimming and bucking of 12′ logs by man-power) per net working hour is given by the formula(1).
2. The production rate per day is given by the formula (2).
3. The results of time-study relating to the varied conditions of trees and for the separate stages of the operation are shown in the formula (3)-(9).
4. For the economy of the intensive utilization, the critical condition is given in the following equation, in which the production rate and the utilization percentage by volume are taken into account.
where, R′ =Utilization percentage by volume in the usual logging operation and in the intensive operation respectively.
L, L′=Production rate per day per man.
G=Stampage cost (Unit cost including measurement overheads)
E=Production cost (Unit cost of log making)
x=Wage of worker per day per man.

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