“…For example, positive impact of income on WTP is witnessed in studies by Westerberg et al, 2010;Ghosh and Mondal, 2012;Birol et al, 2006;Othman et al, 2004;Birol et al, 2011;Hanley et al, 2006;Oglethorpe and Miliadou, 2000;Bliem et al, 2012 andNuva et al, 2011.The positive effect of membership in NGO on WTP also reported by Oglethorpe and Miliadou 2000;Pattison et al 2011. The negative interaction between number of people per household with the level 3 of natural scenery indicates that large families have lower WTP compare to small size families. Our results were similar to some other previous studies (Perez-Verdin et al, 2011;Hammitt et al, 2001;Pattison et al, 2011). The negative interaction between the level 3 of biological diversity and age was supported by the results of study conducted by Oglethorpe and Miliadou 2000.…”