Abstract
In the Kiyosumi area of the University of Tokyo Chiba Forest, located in the southeast of the Boso Peninsula, we analyzed the relationship among Sika deer (Cervus nippon) population density, damage caused by Sika deer to planted Sugi (Cryptomeria japonica) and Hinoki (Chamaecyparis obtusa) , and the mortality and height growth of Sugi and Hinoki. Damage to planted Sugi varied extensively from 0% to 100%, whereas that to Hinoki was greater than approximately 60% or less than approximately 10%. In plots where damage was continuously high and cumulative damage in the 4th year had increased above 300%, the cumulative mortality of planted Sugi increased until the 5th year, whereas that of planted Hinoki, with the exception of one plot, remained low. In plots where damage was continuously high, the Sugi trees appeared to be able to grow taller than the height where deer can eat, although their height was approximately half that in plots where damage was low and cumulative damage in the 3rd year was less than 200%. Furthermore, in some Hinoki plots in which damage was continuously high, the trees showed almost no growth in height.
