Spatial distribution pattern, scale and gap characteristics of Pinus armandii population in Qinling Mountains, China

Abstract

Based on the data collected from 27 plots of the Pinus armandii community in Qinling Mountains, we studied the spatial distribution pattern, scale, and gap characteristics of the P. armandii population. The results showed that the population had a clumped distribution before age 50. At the age range from 15 to 25, though the population tended to be distributed randomly, the distribution was still clumped. The population distribution at the age range from 40 to 50 was at the transitional stage from clumped to random. After age 50, the population started to be senesced, the distribution pattern turning from clumped to random. The distribution pattern scale of P. armandii always changes with the development stage of the population, being 100 m² in general. The gap size of P. armandii population was similar to its distribution pattern scale, and the gaps of 80 130 m² occupied 59% of the total. Because of the better light and nutrient condition in the gap, P. armandii seedlings grew well, which helped the population keep its stability through mobile mosaic circling .