I would like to specially thank my supervisor Karl-Olof Bergman that supported me in the field work and the whole parts of the project. Also thanks to Lars Westerberg and Per Milberg and Tom Lindström for support in statistical analysis and helpful suggestions as well as Zeinab Moradinour and Davoud saffar and Ali Moradinour for support in programming and graphics. Also Länsstyrelsen Östergötland​ that provided the maps for my study. Finally my appreciate and respect to Swedish institue for giving the upportunity to study in Sweden and also my family and my friends for all of warm and kind helps and supports.