Age Structure and Spatial Patterns of An Endangered Plant Nothotsuga longibracteata

Nothotsuga longibracteata,a relic plant endemic to Southeastern China,is now distributed in highly isolated mountain forests.The species is important for Pinaceae in the studies of phylogeny and phylogeography.The present paper based on field investigations to a well conserved natural N.longibracteataN.logibracteata population.The age of all individual plants in the plot were measured by taking tree cores,and all individuals were mapped. A total of 215 N.longibracteata individuals were grouped into 16 age-classes. The spatial patterns analysis was conducted using Ripley’s K(d).The results showed that the companion understory species were mainly broad-leaved evergreen trees which seemed to hamper the seedling regeneration of N.longibracteata.The age structure of N.longibracteata showed the population has experiments three main regeneration periods which might have been interrupted by disturbances.The data showed that in the radius of 35 m,the N.longibracteata population younger than 60 a has a patchy spatial distribution,the pattern then becomes random as the age increases over 60 a.The spatial structures in different age classes seemed to be highly influenced by natural regeneration characters, seed dispersal patterns, intra-and inter-specific competition and self-thinning processes.These results can be used as a baseline data for formulating conservation strategies of N.longibracteata in the reserve.