| Budget Amount *help |
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1988: ¥300,000 (Direct Cost: ¥300,000)
Fiscal Year 1987: ¥1,700,000 (Direct Cost: ¥1,700,000)
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| Research Abstract |
In this study, the following two studies were performed during two years.
1. Studies-on variations in mixed stands of Quercus acutissima and Q. variabilis and in pure stands of Q. acutissima. In mixed stands, Q. acutissima, Q. variabilis and their hybrids were obseved. These three species could be easy distinguished by the state leaf hair and the thickness and quality of outer bark. There was a positive correlation between the quantity of leaf hair and the thickness of outer bark. In Q. variabilis, the thickness of outer bark increased with increasing breast height diameter. In the secondary stands of O. acutissima, four types were observed on bark form. the type of bark form, the thickness of bark and the state of bark splits varied according to individual trees and localities.
2. Studies on the growth, characteristics and timber price of old pine trees and some useful broad-leaved trees. Old trees of the Bakaku pine were 180-200 years in tree age, 70-110 cm in breast height diameter. The color of heart-wood was reddish brown or light reddish brown and the percentage of heart-wood was 65 % on average. The diameter growth was quick during the first 50-80 years and thereafter it decreased slowly. In broad-leaved trees, two types of growth, namely, early growth and late growth, were recognized. Prunus jamasakura grew into a diameter class suitable for utilization within 50-60 years, while Zelkova serrata took more than 150 years to attain a suitable for lumber. The log price varied with species, wood quality and log size. In pine trees and Z. serrata, log prices showed a rising tendency with the increasing diameter of logs.
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