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No.6 (1959/8) >

Title :沖縄本島北部の天然生リュウキュウマツ(Pinus luchuensis Mayr)幼令林分の構成状態と生育について(予報)
Title alternative :Studies on the stand composition and growth of the natural young Luchu pine (Pinus luchuensis Mayr) forest in the northern district of Okinawa Island (Preliminary report).
Authors :大山, 保表
Authors alternative :Oyama, Hohyo
Issue Date :Aug-1959
Abstract :The research was made on a young forest of naturally grown. Luchu pines (Pinus luchuensis Mayr) in Yona Forest of University of the Ryukyus which is located in the north of Okinawa Island. According to the density of trees, the forest was divided into seven (7) plots, and the trees in each plot were classified into four (4) hight classes in accordance with the height of the trees・・・・classes : 0-3 m, 3-4 m, 4-5 m, and 5 m up. As the result of measurements of the amount of leaves, volumes of stems and branches, and stem anylysis of every tree, the following were found : 1. The ages of the trees are between 7 and 12 years. The plots are narrow areas where the land conditions are similar. The number of trees per ha in each plot is between 8,426 and 20,899. The number of trees in each plot is vanous. 2. The average height of trees in the plots are between 3.88 and 4.31 m. The average height of trees of the tallest height class (over 5 m) which are not suppressed are between 5.18 and 5.66 m. The calculated average age of trees in each plot is between 7.75 and 8.75. 3. In each plot, the trees which belong to the height classes of 4-5 m (average trees) and 5 m up (dominant trees) are more numerous. One plot has 48 % of those classes of trees; another, 53 %; and the rest of the plots, between 60 and 75 %. 4. Since the Ryukyuan pine is light demander, the difference in height due to age and the growth rate while small is closely related to the differences in the growths of diameter, the volume of stem, the amount of leaves, the volume of branches, etc. 5. The growth in the first one and two years is relatively small, and the difference in height is small; but in the second to third year, the growth rate of trees is generally increased, and the difference among the trees becomes greater. From the fourth to fifth year on, the difference of the growth rate of the trees becomes much more greater, -there are some which show very great growth rate, and some which show smaller growth rate than when they were in the second and third years. 6. The diameters at the land level of 7 year old trees are between 1.63 and 6.30 cm, and those at the height of breast are between 0.98 and 8.08. There are great differences of diameters among the height classes. The trees of the Class 5 m up have especially greater diameters and those of Class 4 to 5 m have relatively large diameters, but those of the smaller height classes have much smaller diameters. 7. The stem volume of each tree of 7 years old is between 0.0002025 and 0.0049450 m^3 That of Class 5 m up is the largest, that of Class 4-5 m is relatively large, but those of the smaller height classes have much smaller volumes. The tree of Class 0-3 m has especially small volume.
8. The stem volume per ha of each plot is between 40,880 and 26,530 m^3, dry weight of leaves is between 4.72 and 2.32 tons, and the branch volume is between 7.09 and 2.79 m^3. In 1958, the previous year of the year the research was done, the growth of stem volume was between 2.83 and 1.27 m^3. 9. The quantity and increment of stem per ha are closely related to the distribution of the numbers of trees in the height classes. The plots which have 9,927 to 11, 905 trees that belong to Class 4 m up are greater. The lesser the trees of Class 4 m up, the smaller. 10. The increments of stems of the four height classes in 1957 are ranged from 0.0000443 to 0.0016760m^3, and in 1958 they are from 0.0000548 to 0.0017474 m^3. There are great differences among the height classes. It is greatest in Class 5 m up, and relatively great in Class 4-5 m, but it is much more smaller in the smaller height classes. Especially it is much smaller in Class 0-3 m, which indicates slow growth due to suppression. 11. The branch volume of a tree in each height class is from 14 to 1797 cc. It is especially greater in Class 5 m up; and the smaller the height classes, the smaller the volume. The branch volume per ha in each plot is from 2.79 and 7.09m^3. 12. The dry weight of leaves per tree in the height classes ranges from 28 to 940 gr; the upper height classes are greater. 13. The increment of volume of stem per one gramme of dry weight of leaves in each height class in 1958 is between 0.73 and 4.14 cc. It is highest in Class 45 m, and is slightly smaller in Class 5 m up, and Class 3-4 m, but it is very small in Class 0-3 m. 14. The stem volume, quantity of leaves, stem increment per unit of leaves, etc. per ha in each plot are closely related to the number of trees belonging to Class 5 m up and Class 4-5 m that are of highest and average trees; the greater the number of these trees, the greater these quantities. Therefore, it is important in raising Ryukyuan pines to increase the number of trees evenly growing in height by sowing as many seeds as possible and making them germinate evenly.
Type Local :紀要論文
ISSN :0485-7828
Publisher :琉球大学農家政工学部
URI :http://hdl.handle.net/20.500.12000/24994
Citation :琉球大学農家政工学部学術報告 = The science bulletin of the Division of Agriculture, Home Economics & Engineering, University of the Ryukyus no.6 p.38 -85
Appears in Collections:No.6 (1959/8)

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