The evaluation of spatial distribution pattern of Indicator species forests of Ghalarang protected area in Ilam province

Today the recognition of spatial pattern of plant population is very important in administrative planning and ecological studies and without any spatial information and spatial pattern of the distribution of population in societies the implementation of every program will face problems. This study is investigating the spatial pattern of tree and shrub species in Protected Area of Ghalarang in Ilam Province. In this research, an area with 1200 ha of protected area from Ghalarang is selected and then, 30 plots in a grid of 150 * 100 meters of inventory network are evaluated via systematic random sampling. To evaluate the spatial pattern distribution of species of tree and shrub including Quercus brantii Lindl., Pistacia atlantica Desf., Acer monspassulanum L. and Crataegus azarolus L., variance ratio to mean, Morisita, Morisitas’ Standard Index are used. Results showed that variance ratio to mean index for all species are clustered distribution patterns, for Morisita and Morisitas’ Standard Indexes are random pattern for Acer monspassulanum L. and Crataegus azarolus L., and for Quercus brantii Lindl. and Pistacia atlantica Desf. are clustered distribution patterns. Due to the high percentage of frequency of Quercus brantii Lindl. and Pistacia atlantica Desf. species are cluster distribution pattern which is acceptable in all indexes, But in the variance to mean ratio index cluster distribution pattern was not acceptable for Acer monspassulanum L. and Crataegus azarolus L. species, because frequency of this species are very low and has a random distribution pattern.