萌芽によるブナの個体維持機構と立地環境

抄録

Sprouts of beech (Fagus crenata) on various site condition were studied to clarify patterns of the sprouts in "high beech forest type" and "dwarf beech forest type". The ecological importance and the relationships between the sprouts patterns and site conditions were discussed. There are few sprouts of beech (Fagus crenata) in closed stands of "high beech forest type". But within a few years after mast year, there are many seedlings, which were classified into seedlings and "seedling sprouts". The seedlings were died within a few years under the closed canopy. Under small canopy gaps, a few seedlings can survive to recover up to sapling stage and young tree stage and they repeat die-back and recovery by sprouts. Sprouting activities of the beech maintain below 10-15cm in D.B.H. and decrease above the size. Some beech "seedling sprouts" can survive under the open canopy like Fagus japonica. Consequently, the growth of sprouts in the styands of "high beech forest type" depends on the light condition under the canopy. On the other hand, the beech sprouts in "dwarf beech forest type" were depended on topographical condition, such as summit phenomena. The beech trunks were broken by physical damage of deep snow caused by prevailing wind up to the size below 10-20cm in trunk diameter and after recovered by sprouts. The "dwarf beech forest type" was maintained by repetitions of trunk broken and sprouting. Such a sprouting ability of the beech is very important to survive under severe condition like heavy snow area.