Flowering phenology of Betula alnoides under different site conditions was observed and compared at inflorescence, individual and stand levels in an ecotone of two types of soils originated from limestone (site L) and granite (site G), respectively, at Jingxi County, Guangxi. The flowering of both male and female inflorescences lasted two to three days, and male inflorescences normally bloomed approximately fourteen days earlier than female ones at the same positions on a tree. At individual level, flowering lasted four to twenty eight days with flowering synchrony index of Augspurger ( 1983 ) ranging from 0. 160 to 0. 259 in each plot, and majority of trees flowered initially upper canopy, followed by middle and lower parts. There existed no significant difference of flowering duration and synchrony between individuals of site G and L (P ＞ 0. 05 ). And flowering lasted forty to fifty eight days without significant difference of flowering duration between both sites at stand level.%从花序、单株、林分水平上对广西靖西县的一个土石山生态交错区内不同立地条件下西南桦的开花物候进行了观察和比较.结果表明:西南桦雌、雄花序开花持续时间为2～3 d,同一植株相同部位的雌花序较雄花序晚开花约14 d;其单株开花持续时间为4～28 d,开花同步性指数为0.160～0.259,绝大多数植株的冠层开花顺序依次为下层、中层和上层,土山和石山立地间单株开花持续时间和开花同步性均差异不显著(P＞0.05);在林分水平上,西南桦开花持续时间为40～58 d,两种立地间差异不显著.
展开▼
