Abstract
A study was carried out on a 1.4-hectare secondary Quercus serrata woodland in the Musashino Uplands that was last cut more than 40 years ago. It was confirmed from maintenance of the forest floor, including cutting of floor vegetation and sweeping fallen leaves in winter, that the number of Cephalanthera falcata is increasing. Furthermore, the species and diameter at breast height (DBH) of every tree over 3m high were investigated in 1998, 2000, and 2005. Analysis of DBH data showed the change of woodland as follows. The trees that had reached the wood's canopy kept growing up, and the diameter increased. Quercus serrata and Styrax japonica that had not reached the wood's canopy height had withered. However, Carpinus tschonoskii and Aphananthe aspera were growing steadily from infant trees to tall trees. In the future, dominant tree species will change gradually as they compete for light. However, the light condition at the wood floor will not change much. In order to preserve the diversity of floor vegetation indicated by the numbers of Cephalanthera falcate individuals, it is necessary to do the maintenance of the forest floor in winter in this secondary Quercus serrata woodland.
