The purpose of this paper is to report the results of experiment conducted to understand the effect of cutting method and frequency on the yield and survival of
A. marina which is one of constituent of mangrove forests.
Three experiments were conducted in the year of 1986 and 1987. The summary of experiments are as follows:
1.
A. marina is not tolerant to frequent defoliations. All plants died when plants were cut 3 to 4 times in a year. When plants were harvested once or twice in a year, if all leaves were removed, some of plants were dead. As regrowth of
A. marina after cutting is not so vigorous, it seems recommendable to use biomass of
A. marina rather than regrowth.
2. When plants were cut at the old stems, some of plants were died, and even survived, plant vigor were weakened seriously. When plants were harvested horizontally a half of plants, or leaves of above half of plants were harvested, all plants were survived, suggesting that this partial harvest is the safty way of utilization and conservation of
A. marina.
3. All plants were survived after harvesting of 3 to 4 times in a year, when leaves above half of plants or horizontally a half of plants were harvested.
Dry matter yield per unit area are the highest at plot harvested twice in a year. As cutting frequencies were increased, the total yield in a year were decreased sharply.
From results of these experiments conducted two years, it is concluded that the efficient and safty method of utilization of
A. marina seems to be partial defoliation with less frequent cuttings. The method removes all of leaves instantly causes death of individual plant and distruction of the vegetation of
A. marina.
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