广西雅长林区铁坚油杉种群结构分布研究

【目的】掌握广西雅长林场林区内铁坚油杉(Keteleeria davidiana)天然林的种群变化趋势,为该种群在桂西北地区的保护、恢复和利用提供参考。【方法】采用统计学方法,在林区内选定4个代表性样地,从大小级、空间分布格局和种群更新方式3个方面,比较不同样地铁坚油杉种群变化的差异。【结果】4个样地铁坚油杉种群的大小级结构各都不完整,均出现不同程度的缺失现象。4个样地铁坚油杉种群的大小级结构不相同,分别为衰退型、增长型、成熟型和稳定型。铁坚油杉纯林的种群以集群分布为主,铁坚油杉混交林的种群则以均匀分布为主; 在2 m×2 m和4 m×4 m网格尺度下,相同样地的铁坚油杉种群空间分布格局发生变化,铁坚油杉纯林由均匀分布向聚集分布转化,铁坚油杉混交林由聚集分布向均匀分布转化。自然条件下,4个样地的铁坚油杉种群的更新主要依靠种子繁殖来实现,其次为萌蘖繁殖。【结论】广西雅长林场林区内铁坚油杉种群的大小级、空间分布格局和种群更新方式的动态变化主要受其林分的群落结构和郁闭度的影响,因地制宜是保护、恢复和利用该种群的有效措施。

Ecological study of Keteleeria davidiana populations of Yachang forest farm in Guangxi Zhuang Autonomous Region

Objective] A comprehensive understanding of the trends of the Keteleeria davidiana populations in its natural forest of the Guangxi Yachang Forest Farm could provide a basis for its protection,recovery,and utilization in the northwest area of Guangxi.Methods] Four representative plots in the forest were selected and assessed using mathematics statistics.The differences in the dynamic changes in K.davidiana populations were analyzed with respect to different plot conditions and the size class,spatial distribution pattern,and regeneration of the trees.Result] The size class structures of the four plots were incomplete and were missing different sizes.The size class structures of the four plots were different,they were recession,growth,mature,and stable types.K.davidiana pure forest had a clustered distribution,whereas K.davidiana mixed forest had a uniform distribution.However,the spatial distribution pattern of K.davidiana populations varied in the 2 m × 2 m and 4 m × 4 m grid scale,K.davidiana pure forest changed from a uniform distribution to a clustered distribution,and K.davidiana mixed forest changed from a clustered distribution to a uniform distribution.The regeneration of K.davidiana populations relied on seed breeding followed by sprouting reproduction.Conclusion] The dynamic changes of the size class,spatial distribution pattern,and regeneration of K.davidiana populations in the Guangxi Yachang Forest Farm are affected by the community structure and the canopy density.Considering the circumstances is required in determining effective measures for the protection,recovery,and utilization of K.davidiana populations.