Assessment of intra- and interspecific interactions of wild pistachio (Pistacia atlantica Desf.) and wild almond (Amygdalus spp.) using spatial analysis in mixed stands of Baneh Research Forest, Fars Province, Iran

Intra and interspecific interactions of plants is one of the important processes in establishing spatial structure of plant communities in semi-arid regions. Additionally, the interactions can be applied in management and rehabilitation of vegetation in these regions. This study was aimed to investigate the spatial pattern of wild pistachio (WP) (Pistacia atlantica Desf.) and wild almond (WA) (Amygdalus spp.) in Baneh Research Forest of Fars province to identify their interactions. In two 150 m × 150 m sample plots, the spatial positions of 798 individuals of two species and their crown diameters were measured. Uni- and bivariate g(r), O-ring, D(r) and kmm(r) were applied to explore the spatial patterns of species. The results showed the heterogeneity of spatial patterns of two species individuals, as well as lower density and higher mean crown area of WP. Moreover, WP and WA individuals were located in mixed clusters, although the positive interaction of conspecifics was stronger than heterospecifics. In small scales, density of conspecifics was almost two times more than heterospecifics. Furthermore, the positive interactions of conspecifics resulted in intense intraspecific competition that negatively influenced their crown areas (p < /em> < 0.05) and was more in WA (in 3 m distance between conspecifics, crown areas of WA and WP were 60% and 20% less than mean, respectively). In general, it was concluded that a mutualistic relationship exists between WP and WA in the study area as a result of their facilitative effects. The quantitative results of this study can be used in silvicultural treatments such as plantation.