Relationship between Pinus taiwanensis seedling regeneration and the spatial heterogeneity of soil nitrogen in Daiyun Mountain, southeast China

Abstract Forest soil plays vital importance on plant community pattern formation, ecosystem productivity and ecological restoration. The relationship between the regeneration of Pinus taiwanensis seedling and the heterogeneity of soil nitrogen (N) in Daiyun Mountain National Nature Reserve (DYMNNR) were determined using geo-statistics method and geographic information system (GIS) technology. The results showed the regeneration of P. taiwanensis seedlings conformed aggregated distribution. The contents of soil total nitrogen (TN), available nitrogen (AN), nitrate nitrogen (NO3−-N) and ammonium nitrogen (NH4+-N) presented moderate variability. The optimum semivariance model for TN and AN were spherical model, while those of NO3−-N and NH4+-N were exponential model. The N heterogeneity mainly dominated by spatial autocorrelation ranging from 11.06 to 21.30 m. The distribution of TN, AN, NO3−-N and NH4+-N was anisotropic, and an obvious mosaic pattern of distribution appeared with zonal and patchy characteristics. High levels of N all appeared in the central, south central, and southeast directions of the study plot, while lower levels of TN and AN distributed in the southwest and north central directions. Low levels of NO3−-N and NH4+-N were mainly located in the eastern and western directions of the study plot, respectively. Higher N resulted in better survival possibility for P. taiwanensis seedlings, which displayed obvious habitat preferences. This study provides guidance relating to soil sampling design and the practice of natural management of P. taiwanensis forest.