Primary studies on the regeneration of the pine (Pinus densiflora) landscape forest. I

Pine seedlings, so called sun trees, do not perfectively under the shade circumstance in the landscape forest. In order to maintain the fine view of the pine forest, we must study how to regenerate these forests with pine seedlings. It is the most important problem that, in the landscape forest restricted the cuttings, we ascertaine the minimum density for the harmanious regeneration of these trees.This investigation was performed to clearfy the successional form of the pine forest and estimate the above tree density having the regenerational possibility. The results obtained are as follows:1. In the seto-naikai seaside district, the pine forest has been shifting from pine to ubame-gashi (Quercus phillyraeoides A. Gray) via hi-sakaki (Eurya Japonica Thunb.) type.2. In inside district, it has been shifting from pine to sudajii (shiia Sieboldii Makino) via hi-sakaki type.3. These differences between sia-side and inside are seemed to be as a result of the influence of the water condition (including of a air humidity, water potential it the trees, and soil water).4. The most optimum density for pine regeneration was 400 trees/ha 600 trees/ha.