Responses of Herbaceous Species to Fire in Persian Oak (Quercus brantii) in Coppice Forests

Zagros forests are one of the important natural ecosystems in Iran with high plant diversity and variety of plant communities. In recent decades, fire events have frequently occurred in some of these ecosystems. The purpose of this research is to investigate the composition and diversity of herbaceous species after nine years of fire occurrence in the forests of Zagros in western Iran. For this purpose in 2015, an area of 40 ha that had burned in 2006 was selected and compared with the unburned area (control area). In both areas, 80 plots were selected. The optimal size of plots was determined based on Whittaker's nested plot sampling and minimal area method. Then, vegetation cover percent of each herbaceous species was estimated according to Van der Marel criterion in each plot. The results showed that the fire reduced the diversity, evenness and richness indices, but this decrease was not significant between Shannon-Wiener (P= 0.57) and species density index (P= 0.06). Species Avena fatua with 21.51 and 18.56% had the highest coverage in the burned and control areas, respectively. In addition, the average of herbaceous percent cover was significantly higher in the burned area (P<0.05). Also, Fabaceae, Asteraceae and Poaceae families were the most important families in both areas. The overall results of this study revealed that many species are able to restore their primary conditions over time.