Study on functions of reed communities and their growth factors on lake shores.

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A series of field surveys on reed growth were conducted at the test plantation site located on a Lake Biwa shore near the Hayama River mouth. Reeds were transplanted in more than one thousand test lots on the late October 1997. Each lot had different attributions on plantation methods, grand level, reed density and distance from the shoreline. Observations of reed growth were conducted every month during the next two years, and the following conclusions were drawn from analysis of observation results : (1) Out of 1081 test reed lots planted in 1997, 449 lots failed to grow, which were mainly planted with the Bittmann Method and the Root Method, while the other methods produced 89% in survival ratio, especially high percentage (98%) in the Mat Method. (2) Average density of reed in the autumn is 86.6, 67.8, 65.3 and 20.6 stalks/mィイD12ィエD1, respectively for the Mat Method, the Pot Method, the Sandbag Method and the Big Stump Method. (3) The erosion exceeding 12 cm depth had adverse effects on reed growth, while the erosion less than 4 cm did not make any difference abstraction on reed growth apparently. (4) All of the factors (transplantation methods, sites, dates and any of their combinations) are statistically proved to have some significant influence on the reed growth variation with a risk less than 0.1%. The contribution of transplantation method on reed growth was 20% of the whole variation.