The colored symptom at lower crown position was studied in a young Sugi (Cryptomeria japonica) plantation on sandstone and phyllite of Paleozoic strata in the province of North Kanto area. Mg concentration in current year's needles and Ca concentration in one year's needles of symptom trees were low compared with normal trees. Ca and Mg concentration in both current year's needles and one year's needles decreased in the order of normal, red-yellow, red and dark-red trees. The soil of the young Sugi plantation with the colored symptom was low in pH, exchangeable Ca and Mg. Absorption of N, P, K and tree growth was increased by N-P-K fertilization. However, because the soil was low in exchangeable Ca and Mg, absorption of Ca and Mg accompanied with the growth was not increased. As a result, Mg deficiency symptom appeared at lower crown position. Mg foliar fertilization of colored symptom trees resulted in increased tree growth and reduced symptoms. Mg broadcast fertilization reduced the symptoms to some extent also, but decresed the exchangeable Mg and Ca concentration in needles. Therefore, it is recommended to use Mg with Ca fertilizer and not to fertilize with Mg only.

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Remains J. Jap. For. Soc. 60: 49-55, 1978 The writers studied the qualities of excavated ancient charcoal using a magnifying scope, proximate and thermal analysis, atomic absorption spectrometry, etc. The charcoal had much coloured ash, which contained a fair quantity of metallic components compared with that of modern charcoal. The results are as follows: (1) The surface structure of the excavated ancient charcoal is similar to that of Quercus sp. and Pinus sp. charcoal, and the excavated charcoal has much volatile matter and a little fixed carbon. They may be identified with the uncarbonized substance in modern charcoal. Then, it may be said that they came into existence due to the decomposition of amorphous matter over a long period of excavation. (2) The excavated ancient charcoal has more ash (7_??_16%) than modern charcoal, and especially, there are plenty of metallic components of iron in the ash. The writers presume that those metallic components might have been adsorbed by select-adsorption from the soil water from which the charcoal was excavated, or previously they had contained the metal components as raw materials. (3) The excavated ancient charcoal ash is deeper coloured than modern charcoal ash. It is presumed that this may be because ancient charcoal ash contains greater quantities of various metallic oxides or salts than modern charcoal ash.

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A yielddensity diagram for natural hardwood forest in Hokkaido was devised. It consists of Y-N curves, equivalent mean diameter curves, equivalent boundary diameter curves, and full density curve. Y-N curve is derived from the relation between summation (Y) of individual volume from the maximum diametered tree to a certain boundary diametered one and number (N) of these trees. Equivalent boundary diameter curve expresses the number of trees whose diameters are larger than a certain boundary diameter. Utilizing the yield-density diagram, it would be possible to comprehend quantitative relations among numbers which had been variable depending on the boundary diameter of trees measured, volume and diameter of trees in a stand, and among stands. It could also be utilized as a guiding principle of stand density control, such as thinning.

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Acidic growth substances in the leaves of a clone of six-year-old Chamaecyparis obtusa were extracted every month during one annual growth cycle. Auxins and inhibitors were separated using paper chromatography and assayed by Avena coleoptile straight-growth test. Auxins were comparatively abundant in the growing season (April-October) and scarce in the resting period. Inhibitors were the least in the period when active extension growth occurred and rather steady in a lower level, with little variation in the resting period. The major auxin obtained in April was tentatively regarded as IAA.

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The average number of pollen grains per pollen sac was 821, and pollen sac per male strobilus was 111. It was estimated that a male strobilus produced about 9.11×10⁴ pollen grains. Estimates of the number of pollen grains produced from each tree and from the seed orchard were obtained on the basis of the number of male strobili per tree and pollen grains per male strobilus.

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