| Budget Amount *help |
¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 1994: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1993: ¥800,000 (Direct Cost: ¥800,000)
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| Research Abstract |
In several Chamaecyparis obtusa stands differing in tree density and soil conditions, annual production rates (by number and dry weight) of male flowers, seeds and cones were studied using litter traps, and the production rate of pollen was estimated. Based on these production rates in a productive year, dry matter necessary for producing a single seed (cost), the ratio of this cost to mean seed weight (specific cost) and the M/F and P/S ratios (numerical ratios of male to female flowers and pollen to seeds on a land-area basis, respectively) were obtained and compared with each other. Attention was focused mainly on the differences in seed production sysytem between various degrees of tree density and the lower and upper parts of a slope. High efficiency of seed production was recognized in stands of high tree density under the same soil conditions and on the upper parts of a slope or under poor soil conditions at the same relative tree density. As for the effects of stand age, no differences in cost or specific cost between stands 26 and 77 yr old were evident. However, M/F and P/S ratios and dry-matter production rates of seeds and cones were higher in the 26-yr-old stand. These results indicate a higher efficiency of seed production in the young stand than in the old stand. In an unproductive year, there were no trends in the production rates of male flowers in relation to tree density, soil conditions or stand age.
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