1. This paper deals with the results obtained by the field experiments on the control of damping off of conifer seedlings, by treating soils with pyroligneous acid, sulphuric acid, and organic mercury compound (Uspulun).
2. These experiments were carried out at three forest nurseries with different soil quality at different localities.
3. The experiments were executed by using Latinspuare method. Each test plot was 5 m² at Kasiwabara nursery, Nagano prefecture, and 2m² at Kinuta and Motohatioozi nurseries, both in the Tokyo. prefecture There were 4 replications for each soil treatment.
4. The amount of acids supplied to the soil was fixed at the point where the pH value of soil was lowered to 5.0. Acids were applied about 7-10 days before sowing. After the germination, the numbers of diseased seedlings were calculated every 3 days till the middle of June, and every 7 days afterward.
5. At every nursery, the pyroligneous acid was most remarkably effective for the control of damping off. The effectiveness was still more encouraged by the additional treatment by spraying. uspulun when the damping off broke out seriously. The results are shown in Table 1-4.
6. From the results of another experiment on the effect of soil treatments with pyroligneous acid at various concentrations, it was observed that the most excellent effect was observed when the soil was treated with mother liquor (81 per m²). The results of this experiment is shown by Figure 1. It was noteworthy that at this test plot the mother. liquor was not only harmless to the seedlings, but also suppressed the growth of grasses.

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Considering that the growth-inhibiting sub-stances are contained in the leaf-litter of Aka-matsu (Pines densiflora SILB. et ZUCCl.), Sugi (Cryptomeria japonica D. DON.) and Hinoki (Chamaecyparis obtusa SCEB. et ZUCC.), thewriter carried out experiments to ascertainwhether these substances could inhibit the germi-nation of seeds or not.
The outline of the results is as follows:
1.The water extract from the leaf-litter couldnot only inhibit the germination of seeds, of thesame species, but also could remarkably inhibitgermination of others.
2. The inhibiting effect of the water extract from the leaf-litter could be arranged in theorder of Hinoki, Sugi and Akamatu.
3. On the soil seed-bed which was admixedwith the leaf litter dust, it was recognized thatthe occurance of seedlings was few due to theeffect of the inhibiting substances, and also thegrowth of seedlings was not very good.
4.From the above-mentioned facts, it wasconsidered that the inhibiting substances for thegermination of seeds and the growth of seedlingswere contained in the leaf-litter.

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The longitudinal distribution of radial increment of stems after strong pruning was studied on about 14 years old trees of Pinus densiflora. The ring breadth of strongly pruned trees have been rapidly reduced on the part of stems below the pruned portions. On the stems extremely strongly pruned, the lack of year rings was observed, which have not been disappeared after three years of the treatment. The reduction of radial grow was largest in the first growing season after treatment, and gradually recovered year by year.

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When the quantification of hollocellulose which is separated by using ethanolamine-alcohol solution below 1% concentration, is made, it is clear that its quantity is little influenced by the temperature and time of chlorination and that the quantity of hollocellulose which is recognized theoretically can be nearly separated. When that is done by using ammonia-water-alcohol solution, instead of ethanolamine-alcohol solution, it may also be observed that great success results therefrom.

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1. In the peresent paper the results of the writer's investigation on the cultural characters of three wood-rotting fungi, Lenzites abietina FR., L. subferruginea BERK. and L. trabea (PERS.) FR., causing the brown rot of various coniferous trees were described.
2. The growth habit of the mycelium on seven different media were compared. Among the agar media used, the malt decoction agar and the SAITO's soy decoction agar proved to be the best for all fungi tested, being followed by the Koji decoction agar, the potato decoction agar and the exocarp of citrus decoction agar. The mycelial growth was generally more vigrous in Lenzites trabera and L. subferruginea than L. abietina. At the beginning of their growth the colonies were white changing afterward slowly to light yellowish brown, yellowish brown or dark brown.
3. The relation of temperature to mycelial growth was investigated by culturing the mycelium on poured plates of three agar media incubated at different temperatures. Repeated experiments indicated that the optimum temperature for the mycelial growth of Lenzites abietina seemed to lie at the temperatures from 26°C. to 28°C. It was found also that the mycelium of L. subferruginea and L. trabea grew very vigorously at the temperatures from 32°C. to 36°C. and the optimum temperature was approximately 34°C.
4. The relation of hydrogen-ion concentration to mycelial growth was studied using the potato decoction agar at 28°C. The mycelia of three fungi tested seemed to be able to grow between pH 2.6-3.0 and pH 8.0, and the optimum pH value for the mycelial growth seemed to lie at pH 5.6 (Lenzites abietina) pH 6.2 (Lenzites subferruginea and L. trabea).
5. By BAVENDAMM's method, the writer obtained negative reaction indicating these three fungi as belonging to the group of cellulose dissolving fungi.

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The authors found a tree of Cryptameria japonica which retains their cones still green in the spring, and made germination test of seeds in them. Cones which ripened in the autamn of 1950 were still green in the spring of 1953 when test was discontinued. Water content of cones and germinability of seeds showed minimum change through two years, as far as they stay on the tree. Germination per cent fluctuated with individual cones, but it was not affected by cone's bearing on the tree.

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The daily increment of stem diameter were successfully measured on a standing tree, by means of application of a dialgauge graduated
with 1/100mm. scale. The dialgauge was fixed on a wood piece which was set on the stem. (Fig. 1) By this equipment, followings become evident, that in a Paulownia to mentosa, of which, yearly radial increment was 25mm, the growth began at the same time with the opening of the winter buds and ceased at the time when the leaves began to shed. (Table 1); The maximum daily increment was measured in July, which was more than 0.4 mm. per day in radius (Table 1). The amount of daily radial increment fluctuated day by day as shown in Fig. 3. The results of every two hours measurement showed that the maximum increment in a day occured in afternoon. (Fig. 4)

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