WBC-VIII-Vol.4 – Resources – Forestry, Plantations and ... - BambuSC

Discussion
As of the research in 1990, it was concluded that P. bambusoides forest did not finish the recovering process
from flowering completely and that tree species tended to extend their territories (Yoshida et. al 1991).
Nevertheless, the results of the following vegetation research in the mixed bamboo forest indicate that, in some
cases, P. bambusoides does not continue to decline its territory and begins to defeat tree species again. This is
clear from the decrease of the number of individuals and number of tree species during 16 years. Especially, the
decline of planted trees, Cryptomeria japonica in this research site, caused by suppression of bamboo is
conspicuous. Furthermore, even the evergreen broad-leaved shrub species tend to decline when they do not
have enough capacity to make coppice shoots. Also the tall Ulmaceae species, which are forming forest canopy
with bamboo, are presumed to decline because of the lack of succeeding seedlings and saplings, except in case
with large disturbance.
P. bambusoides is thought that its activity was still increasing in comparison with the condition of 1990, and that
the process of recovery from flowering had been continued for 25 years after flowering. However, it is
estimated that the tendency of increase of its activity is slowing down after 1995. This presumption is followed
by the increase of the percentage of small new culms and by the decrease of the number of large culms.
Nevertheless, it is difficult to identify the cause whether to the end of process of recovery from flowering or to
the careless management condition.
In this research it was indicated that the vigorousness of P. bambusoides after flowering was continued at least
for 25 years. Tree species, which enlarged the territories during the recovery of bamboo, were suppressed by
bamboo again. The bamboo forest vegetation is considered to need more than 25 years after bamboo flowering
to stable the vegetation condition which means the coexistence of bamboo and trees. Moreover, at the stable P.
bambusoides forest, it is shown that a large amount of new culms is recognized on every two or three years, and
on each following year new culms are comparatively small and died young.
Now, in Japan, the resumption of management, like density control of bamboo culms, fertilizing and so on, is
expected to set the domestic supply of materials for bamboo industry on the suitable way and to restore it in the
stable condition before the flowering of P. bambusoides.
Reference
Kasahata, K. 1971. Flowering of bamboo. Iden, 25(8), 83-90 (in Japanese)
Yoshida,H.; Sakamoto,K.; Shibata,S. 1991.Landscape change of riparian forest and its stand structure in the
east-coast plain of Lake Biwa. J. Jpn. Revegetation Technology, 17(1), 37-47 (in Japanese with
English abstract)
VIII World Bamboo Congress Proceedings Vol 4-142