1) The pine forest established on coastal sandy areas at Hamayoshida, Miyagi Pref. were investigated from the ecological standpoint.
2) Within the forest investigated eight communities were found occurring in zonation towards the interior. Pinus Thunbergii (“Kuromatsu”) communities with strand plants as undergrowths were found on the seaward parts, while P. densiflora (“Akamatsu”) communities with many inland plants on the interior parts. The zonal arrangement of the communities was accompanied by the zonal change of such properties of the soil as moisture, pH, Ca-and Cl-content etc. The maritime character of which weakened inwards. Accordingly, it may be said that these soil properties, as well as meteorological characters, control the structure of communities.
3) Some precise examples of water levels influencing greatly upon the structure of pine forests will be given as follows :
When the water level is higher than 25-35cm in summer, the pines are unable to grow, and when lower than 50cm, the normal types of forests appear. On the intermediate site occurred the forests with such hygrophytic undergrowths as sedges.
The inhibiting effect of underground water upon the establishment of pine forests seems to be accelerated by the increasing content of chlorids.

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1. I devised the following EMPIRICAL FORMULA for making easier and more accurate the measurement of the diameter of tree.
d_o=0.4D+0.6d
d_o......DIAMETER
D......MAXIMUM AXIS of the cross section.
d......GREATEST AXIS that is at right angles to the MAXIMUM AXIS of the cross section.
2. By this EMPIRICAL FORMULA, Measurement of the cross section-area was actually made of 66 “SUGI” (Criptomeria japonica D. DON) and 50 “AKAMATSU” (Pinus densiflora SIEB. et ZUCC) Produces from ONSEN-GUN, EHIME PREFECTURE, SHIKOKU, JAPAN.
3. The results thus obtained were compared respectively with those secured by using the following popular FORMULA, d_o=D+d/2
4. and I found that my method is superior to the above mentioned method in the probabilities of POSITIVE, NEGATIVE, MAXIMUM ERROR, as well as STANDARD DEVIATIONS.
5. I may confidently say, therefore, that my method is the more practical and accurate one for use in determining the diameter of trees.

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As the formation of dune lake is accidental, its existence is very rare in the world. Its formation necessitates to fulfil following five conditions; (1) free development of sand dunes on the off-shorebar without natural or artificial obstacles, (2) the effectiveness of prevailing wind along the direction of valley, (3) the formation of the definite barin between two duneranges, (4) the catchment area and (5) the height of sand dunes.

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Purpose
To study various species of trees, whether leaves are combustible with or without flame, would contribute :
i) to find one condition to choose trees for the standard plantation of fire prevention,
ii) especially to find fit species for plantations standing very near to houses, because the leaves bursting into flame may cause a danger of spreading fire instead of being a fire cordon,
iii) to to examine experimentally the reliability of the reports on flameless combustibility of leaves written by forerunners who met with and observed past conflagrations : for instance, Pinus palustris were combustible without flame, and Cinnamomum Camphora blazed up easily etc.
Experimental methods
Fresh leaves were carried, hanging from hooks on a rail into a cylindrical furnace maintained at constant temperature by a trasformer box. On leaves were made observations of the type of combustion, measurements were taken of the time required to blaze up. They were repeated several times in a series of 7 trials.
Results
The experiments were made in March and April 1951, in which were used most of popular evergreen trees and shrubs for landscaping in Japan. Results obtained are shown in Table 1, regarding
1. ratio of flameless combustibility at 500° and 550°C,
2. time required to blaze up,
3. the type of combustion at 500°C heating. This is classified as follows :
A₁ No explosion; furiously jetting vapor and gas.
A₂ No explosion; calmly jetting vapor and gas (sometimes with faint crepitations)
B₁ Sharp, strong cracklings.
B₂ Successive weak cracklings.
B₃ Powerless explosions.
Discussion of results
1. The flameless combustibility of leaves depends probably on the heating temperature.
It could be hardly seen in the furnace at temperatures higher than 550°C among the plants in Table 1.
2. No correlation could be found between the flameless combustibility and the time required to blaze up. Probably the latter may be connected with the evaporation surface area, accordingly to the thickness of leaves, while the flameless combustibility may depend on existence of any conditions, which prevent the kindling of the inflammable gases produced by thermal decomposition of leaves.
3. Flameless combustibility of leaves at 500°C could be seen more often among broadleaved shrubs than among conifers and broad-leaved trees.
The excellent species in this regard are Camellia Sasanqua, Chamaecyparis pisifera, Daphniphyllum macropodum, Euonymus japonica, Fatsia japonica, Ilex rotunda, Ilicium religiosum, Myrica rubra, Nerium indicum, Osmanthus ilicifolius, Sciadopitys verticillata, Thujopsis dolabrata Viburnum odoratissimum.
The worst species are Pinus densiflora, P. Thunbergii, Cedrus Deodara, Magnolia grandiflora, Osmanthus fragrans, Quercus glauca.
4. Generally speaking, leaves take more time to blaze up among conifers than among broad-leaved trees and shrubs. Species taking long time to blaze up are Chamaecyparis obtusa, C. pisifera, Pinus palustris, Taxus cuspidata; Daphniphyllum macropodum, Ligustrum japonicum, Osmanthus ilicifolius, Pinus densiflora, Podocarpus macrophylla, Sciadopitys verticillata, Ternstroemia japonica, Viburnum odoratissimum.
Species on the antipole are Cinnamomum Camphora, Myrica rubra, Osmanthus fragrans, Shiia cuspidata, S. Sieboldi.
5. In this experiment Viburnum odor. (a conventional fire prevention tree was excellent both in regard to the flameless cobustibility and to the time required to blaze up. Likewise to be recommended is Thujopsis dolabrata.
Myrica rubra, a popular tree for fire prevention of forests in Japan was excellent in regard to the flameless combustibility, but it was one of the species which took the shortest time to blaze up.

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In the ordinary designing practice of wooden girder-bridges, paving planks are commonly assumed to be simple beams. However, in fact they act on as continuous beams, e. i. any applied load is transmitted by planks and borne by all girders. The author analysed the load-distrbution, and the proportions of distributed load borne by each girder are theoretically calculated. It is suggested by the numerical examples that, the load-transmitting effects of paving planks are considerably large, and therefore, they should be taken into account for the design of girder bridges.

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Colors of twenty Japanese and four imported woods which are in wood-technological use in Japan, were observed under an illumination of C by the trichromatic colorimeter which is shown in Fig. 1, and the results obtained are shown in table in the text by the standard XYZ reference system of the International Commission on Illumination.
Hues of twenty-four test pieces range from reddish orange to greenish yellow, though most of these woods have slighte tints. Their colorimetric values are as follows;
chromaticy x=0.33-0.45, y=0.33-0.40
luminosity Y=4.5%-65%
dominant wave length λ=572mμ-596mμ
exitation purity p=12%-53%

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Comparisons of normal wood and compression wood of Todo-fir (green→F. S. P.) when tested in shearing and hardness may be summarized as follows;
1. In normal wood, it has a close relation between specific gravity rings per unit length, but in compression wood, it has not.
2. In both normal and compression wood, specific gravity is in direct proportion to summer wood (see Fig. 3).
3. In shear parallel to grain test, comparisons of normal wood and compression wood are as follows (average values);
τ_n<τ_c; τ_n/r_n>τ_c/r_c; η_n>η_c; τ_nR<τ_nT; τ_nR>τ_bT
where, τ: max. shear stress; η=δ_p/τ_p(cm/kg/cm²); δ_p: shear deformation at proportional limit sress τ_p; r: specific gravity; c: compression wood; n: normal wood; R: radial; T: tangential.
4. In Brinell hardness test, comparisons of normal wood and compression wood are as follows;
He: Hs_??_100:40 (in both normal wood and compression wood)
Hc_??_aS+b; Hn_??_K; Hce (S=100%)_??_pSe^q; Hce(S=100)_??_p'l_f^-q'
where; H: hardness value; e: end surface; s: side surface; S: summer wood at indented part; Se: summer wood of annual ring; l_f: spring wood-with; a, b, k, p, p', q & q': constant.

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A shrinkage test have been made on Madake (Phyllostachys reticulata C. KOCH) grown in Akadomari and Kawasaki village of Sado district. The results of this test on 7 bamboos are as follows.
The shrinkage percentage was calculated based on green dimension to oven or air dry.
1) Table 1. Shrinkage percentage.
In longitudinal dimension, the shrinkage percentage to oven dry is extremely larger than that of to air dry.
2) The shrinkage percentage of Moso-chiku (P. pubescens MAGEL) and Madake, in radial and tangential dimension, is almost similar but in longitudinal, Moso-chiku has larger one.
3) There is no relation between the shrinkage percentage and the height from the ground, as shown in table 2.
4) The minimum value of specific gravity appeared in about one meter from the ground and in other part, increased with the height.

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Die Schneidekante des Messers, dessen Bewegungsgeschwindigkeit v ist, vorrückt auf der Linie parallel zur x-Achse. Die Winkelgeschwindingkeit der Spindelachsendrehung ist w, und v/wa. Wenn es so ist, ist die Gleichung der kurve, die durch die Schneidekante des Messers bei einer Rundschälmaschine verfolgt wird, we folgt:
(1)_??_
wo h die Abstand der Schneidekante des Messers von einer durch die Spindelachse gehenden waagerechten Ebene ist (s. Abb. 1).
(1) zeigt den geometrische Ort des Punkts, der am Ende der Senkrechten liegt, die von einem Punkt auf der Archimedischen Spirale r=R_o cos θ_o-a_??_ auf die Radiusvektor des Punkts gezogen wird und eine Abstand h in der Bewegungsrichtung der Spi ale hat. Wenn man h=0 nimmt, zeigt (1) die Archimedische Spirale θ=R_o-r/a, und auch, wenn h=-a, die Evolvente des Kreises θ=_??_
In der Praxis kann man, in Bezug auf den Freiwinkel, die Kurve als die Archimedische Spirale.
Die Schnittgeschwindigkeit V ist wie folgt:
V=_??_

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The growth-regulating activity certain flavone pigments against wood-destroying fungi was examined under the following experimental conditions in vitro :
flavonoids............distylin (3, 3', 4', 5, 7, —pentahydroxy flavanone) and quercetin (3, 3', 4', 5, 7—pentahydroxy flavone)
substratum..........agar substrate containg cane sugar, asparagine and other inorganic compounds.
fungi................Poria vaporaria Pers and Polystictus sanguineus (L.)Friet.
conditions............average temperature 29.5°C. range of relativé humidity 63-75.
From the difference between these colony-diameters and those of contrast, we found that distylin strongly controls the growth of fungi with increase of its concentration, and in the case of lower concentration it inversely exhibits the growth-promoting activity on Polystictus canguineus (L, ) Fries.

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1. Previously it has been shown by the author that free oxalic acid accumulates in the glucose peptone medium of wood brown-rot fungi, where as it is not the case in most of white-rot fungi. Now the author got the same results on the potato-glucose agar by 39 species of wood rot fungi. This fact is thought that this serves as a good reference to diagnose the form of wood rot of these species of fungi as well as BAVENDAMM's Reaction. This method is very easy but we take care of the time of culture when we test.
2. A brown-rot fungus Poria vaporaria and a white-rot fungus Coriolus veysicolor were cultured on the sawdust of the beech. The decayed sawdust by poria vaporaria was accumulated by free oxalic acid and the pH of the sawdust changed very low, but the decayed sawdust by Coriolus verusicolor was not accumulated by free oxalic acid but was accumulated by oxalate and pH change is negligible.
3. Poria vaporeria can assimilate well many species of hexose, xylose, starch, xylan, mannit, succinic acid, inulin, glycerine and accumulate oxalic acid from these carbon sources. Also this fungus can accumulate it from asparagine.
4. Later the author found a new enzyme which decomposes oxalic acid from white-rot fungus and studied these relationship.

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The influence of addition of chemicals on the ripening process and joint strength of viscose-adhesive has been examined. The chemicals added are metanol, ethanol, ethylene glycol, glycerine, grape sugar, cane sugar, starch, phenol, acetone, dioxan and pyridine. No influence was recognized in the case of acetone and dioxan. The addition of pyridine retarded the ripening slightly, but not remarkable. Alcohols accerelated the ripening and the order of influence was glycerine > ethylene glycol > grape sugar > metanol > ethanol > starch, cane sugar > phenol. The accerelation of ripening by glycerine, ethylene glycol and grape sugar was remarkable. It was obviously observed that decreasing of joint strength with viscose-adhesive was accerelated by the addition of the chemicals which accerelate the ripening of viscose. In the case of the chemicals which do not influece on the ripening the change of joint strength was the same as that of the control.

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