Abstract
In this study, bamboo stand expansion in its above- and belowground parts is examined in a semi natural forest. Areal changes of stand area, stand edge expansion rate, annual rhizome elongation and rhizome age were surveyed. The study site was set up in a bamboo stand in Ibigawa Town, Gifu Prefecture, where there had been no residents since 1987 due to dam construction. Aerial photograph interpretation revealed that the bamboo stand area expanded continuously between 1982 and 2006. The most rapid expansion observed between 1992 and 2003 was due to the appearance of open land with bush around the bamboo stand after tree cutting between 1997 and 2003. The average of stand edge expansion rate calculated by 10 ground control points between 1982 and 2006 was 1.35 m/year. The rate between 1992 and 2003 at 1.37 m/year and the rate between 2003 and 2006 at 2.16 m/year was greater than the rate between 1982 and 1992 at 1.07 m/year. Overall, these results showed that there was remarkable expansion between 1992 and 2006. It can be presumed that the open land significantly contributed to bamboo stand expansion. Further, rhizome was located 2.8 to 8 m outside of the stand edge and rhizome annual elongation was calculated as 1.92 m/year. A correlation coefficient between annual stand edge expansion rate and rhizome annual elongation during the 2003 to 2006 was inversely correlated (p<0.05). In conclusion, the study demonstrated that the bamboo stand expanded rapidly. Additionally, above- and belowground parts expanded alternately in the process of bamboo stand expansion.
