Seasonal Variation patterns of the Soil Seed Bank of Populus Caspica Protected Area, Noor forest park

The aim of this research is seed bank seasonal variation patterns in the Populus caspica reserved forest، Noor forest park. Above ground vegetation sampling were made by Braun-Blanquet method. Soil samples were collected during autumn، winter and spring and were studied using seedling emergence method. Seasonal variation in the soil seed bank during spring، autumn and winter indicated that maximum and minimum average size of soil seed bank were in autumn and spring by 747 and 426 seeding/m2 respectively. Numerical analysis of biodiversity showed that seed bank floristic data did not have differences during the third season، but its eveness in the spring was higer than autumn and winter seasons. Also the results indicate that only 5 tree species including; Ficus carica، Morus alba، Prunus divaricata، Alnus glutinosa and Populus caspica were able to produce persistent soil seed bank. In this case، seeds of P. caspica with average density of 83 seed/m2 were presented only in spring soil seed bank so we are cocluded that P. caspica to be included in transient soil seed bank. Totally، results of this study reiterd that the low seeds germination rate of P. caspica is not due to its low seed viability، but this failure is due to low persistence of its seeds. rather due to the low rate persistence Populus Caspica that has seeds lose their viability quickly، This is due to the failure to provide favorable conditions germination (light and high humidity) rapidly lose their viability.