九宫山红椿种群结构和空间分布格局分析

Analysis of Population Structure and Spatial Distribution Pattern of Toona ciliata in Jiugong Mountain

对九宫山保护区惟一红椿(Toona ciliata Roem.)群落设立2个样地,研究了T1和T2样地种群空间分布格局。通过龄级划分研究种群年龄结构和动态量化分析,以探讨不同样地红椿种群空间结构与分布格局的成因。结果显示,2个样地的种群分布格局在16、25、50、100 m^2时,均为泊松分布;取样面积越大,Lloyd平均拥挤度(m*)和丛生指数(I)越大;T2样地的Lloyd平均拥挤度(m*)和丛生指数(I)值均高于T1样地。T1和T2样地Ⅰ龄级数量分别占总量的41.86%和48.18%,Ⅳ、Ⅴ龄级环境筛与竞争作用加强。2个样地种群动态指数变化差异较大,T1样地为10个龄级,V_Ⅳ、V_Ⅴ、V_Ⅵ为波动;T2样地12个龄级,V_Ⅳ、V_Ⅴ、V_Ⅸ、V_Ⅹ为波动。2个样地种群V_(pi1)=40.83%,V′_(pi1)=2.041,V_(pi2)=49.72%,V′_(pi2)=4.144,均属于增长性种群,天然更新较好,但种群老龄化趋势明显。因此,加强森林抚育,人为制造林窗,将更有利于红椿种群的更新和稳定发展。

2 sampling plots were set up to research the spatial distribution pattern of Toona ciliata Roem. population. The structure of age class and quantitive dynamic indexes were analyzed to identify the causes of structure and distribution patterns of T. ciliata populations in the Jiugong Mountain Region. The result revealed that the distribution pattern in 16 m^2, 25 m^2, 50 m^2 and 100 m^2 grid were all Poisson distribution. Both the David ﹠ Mooreˊs cluster index （I） and mean crowding index （m^＊） increased with the sampling size; and the 2 indexes of T2 sampling plot were higher than those of T1. The quantities of the I age class accounted for 41.86﹪ and 48.18﹪ of the 2 plots, respectively; while environmental sieves and competitive effect intensified in Ⅳ to V age classes. Population dynamics index of the 2 plots changed a lot. T1 plot has only 10 age classes, fluctuated negatively in V Ⅳ, V V and V Ⅵ, with V pi1=40.83﹪ and V′pi1=2.041; T2 plot has 12 age classes, waved negatively in V Ⅳ, V V , V Ⅸ, and V X , with V pi2=49.72﹪ and V′pi2=4.144. Both the plots were growing populations with good natural population regeneration; but the aging tendency was evident. Therefore, the intensification of woods tending, and canopy gaps interfered by human management are conducive to the regeneration and balanced development of the population.