investigation on the elm (ulmus glabra hudson) spatial structure to apply for sustainable management (case study: gorazbon district, kheirud forest)

elm (ulmus glabra hudson) is one of the most valuable species which distribute all over the caspian forests. nowadays, elm is considered an endangered species due to intensive human activities and outbreak of dutch elm disease over the last few decades. to suitable management of elm, there is need to have indices which describe; current structure and its changes across the time. this study besides the description of a family of indices based on nearest neighbor is dealt to quantify the spatial structure of elm in gorazbon district. these indices investigate the positioning, mixture and dbh dimension of elm in relation to neighborhood trees. the data used in this study collected from 243 circular-shaped sample plots with an area of 1000 m2 and the crancod (ver. 1.3) was employed to the data analysis. in this research, in addition to the quantifying of elm spatial structure, deviation between observed and simulated forest was calculated using absolute discrepancy algorithm. the mean values of uniform angle, species mingling and dbh dimension indices for elm in studied forest were accounted for 0.54, 0.9 and 0.32, respectively. these values showed random distributions with a little relative tend to cluster and a high degree of competition with other species and also dbh dimension indicated that elm was conquered in relate to other neighbors. finally, ad values between observed and simulated forest for the above mentioned indices were calculated 21.2%, 32.2% and 13.14%, respectively. monitoring of management activities and evolution of forest ecosystems with above-mentioned indices is useful for conservation of biodiversity, controlling of extinction process and decreasing of environmental destructive impacts.