Carbon Sequestration of Mediterranean Tree Species in the Zagros Forest of Iran

Aims: Despite the many studies on carbon stock and sequestration in Iranian forest ecosystems, the effects and role of Mediterranean species on carbon stock in Iranian forest ecosystems are not well known. To our knowledge, no information is available on the carbon sequestration of Mediterranean species in Iran. This study aimed to quantify the surface soil carbon stock of Mediterranean tree species in the Zagros forest.  Materials & Methods: To this, ten soil samples were taken under the canopy of Cupressus sempervirens var horizontalis, Myrtus commonis, Quercus brantii, and also bare lands from a depth of 0-20 cm. Soil carbon stocks were calculated in each of the studied treatments. One-way ANOVA was used to evaluate the differences among the studied species and bare land for soil physiochemical properties and carbon stock. Multiple linear regression (MLR) using the stepwise method was performed to define the most critical soil factor for soil carbon stock calculation.  Findings: Our results indicated that Cupressus sempervirens represent the highest significant value for soil carbon stock (237.79 t.ha-1). Soil carbon stock in Myrtus commonis and Quercus brantii stands were 122.05 and 91.90 t.ha-1, respectively. Significant differences between Myrtus commonis and Quercus brantii were recorded. The lowest soil carbon stock was recorded in the control site and was significantly lower (27.26 t.ha-1) compared to the other treatments. Compared to the bare land and Quercus brantii stand, Cupressus sempervirens had 872.30 and 258.74 percent higher soil carbon stock, respectively. The higher soil nutrient content under the Mediterranean canopy is due to the higher soil nutrients available. Also, it might be related to the protection made for these species compared to the oak forest. Moreover, soil organic carbon and bulk density represent the best predictors of the soil carbon stock based on the multi-linear regression method.  Conclusion: Reforestation/afforestation programs using Myrtus commonis and Cupressus sempervirens should also be considered for carbon sequestration programs in the Zagros forest, where these species could be planted. Moreover, our results demonstrate that using a variety of tree species, primarily Mediterranean species, would be a proper policy for increasing soil carbon stock in the Zagros forest.

Carbon Sequestration of Mediterranean Tree Species in the Zagros Forest of Iran Keywords:

Carbon sequestration , Mediterranean , Nitrogen , Quercus brantii , Soil properties