Coarse and fine woody debris and mortality rate of Persian Oak estimation in relation to some environmental factors in Zagros Oak forest (Case study: Tange Alamdar, Behbahan)

Forest decline is an important and complicated phenomenon that happened in most world oak forests. This research aims at the determination of mortality rate, the volume of deadwood, and also the designation of the ecological factor affecting these mentioned parameters in Tange Alamdar, Behbahan. To do so, a 50 hectares oak forest was selected and 30 systematic randomized sample plots (25 Are) were established in this site. Within each sample plot, mortality rate, deadwood volume in different classes (coarse and fine dead wood), slope, elevation, landform, and terrain shape indexes, and aspect were recorded. Pearson’s correlation coefficient and one-way ANOVA were used for data analysis. The result indicated that standing dead tree, fallen dead tree, and fine woody debris volume were 7.01, 15.21, and 0.039 m3 ha-1, respectively. Persian oak mortality rate in the studied site was 57 percent and the highest rate belonged to the 10-15 cm d.b.h class. The high rate of mortality had no correlation with elevation and aspect. Also, deadwood volume and number in the different studied groups had no significant correlation with physiographical features. A high level of mortality rate in all of the diameter classes might imply that mortality is not the result of aging but some kind of disturbances. One of the possible reasons for low fine woody debris volume could be related to human disturbances. Overall, reforestation should be considered in the studied site to decrease the mortality rate.