Demography and growth pattern of understory shrubs in a Japanese beech forest.

(1)1995~1997年，对日本山毛榉林内4种灌木的果实产量及其空间分布进行了研究。3种灌木树种间盛产果量远低于乔木，但差异不显著。种子大小和形态也基本一致。(2)4个供试树种的茎死亡率均随着分株大小的增加而迅速下降，但在分株达到开花和播种大小后又略有增加。观察到的规律与报道的很少发芽的树种相同。每年，4种灌木树种通过发芽招募的茎占总茎数的10%-20%。这些萌发的树干第一年的死亡率很低，约为10%。每年都有3个树种的当年苗出现在森林地面上，虽然分布分散，密度很低，但每年都会出现3种树种(山胡椒、白玉兰和草莓)。观察到八仙花通过枝条碎裂进行营养繁殖。

(1) In each year between 1995 and 1997, fruits production and its spatial destribution were studied for four shrub species in a Japanese beech forest. The amount of fruit production in the mast year, which were far less than those of tree species, were rather similar among three shrub species. The seed size and its morphology were also similar among them.(2) In all of four species sxamined, the mortality of stems rapidly decreased with the increase of ramet size but slightly increased again after the ramet reaching the flowering and seeding size. The pattern observed is the same with those reported for tree species which rarely sprout.Every year, 10-20% of the total number of stems were recruited by sprouting for four shrub species. The mortality of these sprouted stems in the first year was very low, about 10%.Every year, the current-year seedlings appeared for three species (Lindera umbellata var.membranacea, Magnolia salicifolia and Viburnum furcatum) in the forest floor, although its distribution were scattered and the densties were quite low.Clone morphology and the interconnection among stems were examined by excavating the clone. Vegetative reproduction by the fragmentation of layred branches was observed for Hydrangea panniculata.