Decreasing shoot density of isolated Miscanthus sinensis patches in the warm-temperate region of Japan
2001
Kobayashi, K. (Shizuoka Seiko Gakuin (Japan)) | Yokoi, Y.
In terms of clonal persistence of Miscanthus sinensis Anderss., the density of live shoots within a patch (""in-trapatch density"" ; no. cm sup(-2) and the cause of its density dynamics were investigated on the basis of the following measurements : the basal area of clonal patches (""patch area"" ; square cm) and the number and configuration (mapping) of their aerial shoots. The intrapatch densities of five patches that were observed over a period of 10years decreased year by year. Most patches with orthotropic (vertical) shoots had higher densities of live shoots at the periphery than the interior, and were hollow-centred as the central densities further decreased with areal expansion. However, the peripheral densities also declined with the central densities. The vacant inner areas intrinsically occurred even in young patches. In the last four years of the study period, three of the five patches showed considerable decreases in intrapatch densities. (The decreasing densities during this period might be at least partly due to the influence of the other patches.) It was also found that the number of shoots within a patch tended to attain the maximum when the patch area approached 2,000-3,000 square m, and then level off through the areal expansion. From these results, the unexpectedly marked declines in in-trapatch density (""patch decay"") can be attributed to the small number of peripheral shoots as well as the continued development of vacant inner areas.
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