调查了在赣北九江市永修县集中分布的狭果秤锤树（Sinojackia rehderiana Hu）群落，对其物种组成、群落结构和更新特征进行了分析。结果表明：群落中乔木种类〔胸径（DBH）≥1 cm〕有27科33属40种（亚种）1 637株，其中，狭果秤锤树的重要值最大，其次是香樟〔Cinnamomum camphora （Linn.） J. Presl〕，二者为群落的建群种；紫弹树（Celtis biondii Pamp.）、尾叶冬青（Ilex wilsonii Loes.）和瓜木〔Alangium platanifolium （Sieb. et Zucc.） Harms〕是群落的共优势种。灌木层植物33种，狭果秤锤树和瓜木的重要值较高；草本层植物24种（亚种），紫金牛〔Ardisia japonica （Thunb.） Bl.〕的重要值最高，占绝对优势。群落林冠层主要为香樟和紫弹树，亚乔木层和乔木下层以狭果秤锤树、尾叶冬青和瓜木数量较多。群落径级结构呈倒J型，狭果秤锤树、尾叶冬青和瓜木等株数较多，集中分布在小径级处；香樟和紫弹树株数相对较少，分布在大径级处。香樟和紫弹树的径级结构为间歇型，更新状态不佳，在群落中的优势地位呈降低的趋势；狭果秤锤树、尾叶冬青和瓜木的径级结构呈L型，更新状态较好，在群落中的优势地位将进一步提升。研究结果显示：赣北九江市永修县狭果秤锤树适应性良好，种群发展稳定，所在群落由阳生性常绿阔叶林向中生性常绿阔叶林演替。

 Sinojackia rehderiana Hu community concentratedly distributed in Yongxiu County of Jiujiang City of North Jiangxi was investigated， and its species composition， community structure， and regeneration pattern were analyzed. The results show that there are 1 637 individuals of arbor species 〔diameter at breast height （DBH）≥1 cm〕 belonging to 40 species （subspecies） in 33 genera of 27 families in this community， in which important value of S. rehderiana is the largest， and that of Cinnamomum camphora （Linn.） J. Presl comes second， and both of them are constructive species of the community; Celtis biondii Pamp.， Ilex wilsonii Loes.， and Alangium platanifolium （Sieb. et Zucc.） Harms are codominant species in the community. There are 33 species in shrub layer， and important values of S. rehderiana and A. platanifolium are relatively high； there are 24 species （subspecies） in herb layer， and important value of Ardisia japonica （Thunb.） Bl. is the highest， which is absolutely dominant species. Canopy layer in this community is mainly composed of C. camphora and C. biondii， while numbers of S. rehderiana， I. wilsonii， and A. platanifolium are relatively large in sub-arbor layer and under layer of arbor. The diameter class structure of community shows an inverse J-shape， and individual numbers of S. rehderiana， I. wilsonii， and A. platanifolium are relatively large， and they have a concentrated distribution at small diameter class； individual numbers of C. camphora and C. biondii are relatively small， which are distributed at large diameter class. Diameter class structures of C. camphora and C. biondii are intermittent shape， and their regeneration status is relatively poor， their dominant positions in the community are lowered； diameter class structure of S. rehderiana， I. wilsonii， and A. platanifolium show an L-shape， and their regeneration status is relatively good， their dominant positions in the community will be further improved. It is suggested that S. rehderiana in Yongxiu County of Jiujiang City of North Jiangxi has a good adaptability， the development of its population is steady， and its community has a succession from evergreen broad-leaved forest dominated by heliophytes to evergreen broad-leaved forest dominated by mesophytes.