Post-fire Sprouting Patterns of Oak Species in the Zagros Forests of Western Iran

This study examined post-fire sprouting patterns in three oak species ( Quercus brantii , Q. infectoria , and Q. libani ) in the Zagros forests of western Iran. It examined the number, type (root and stem sprouts), diameter, and height growth of sprouts over three post-fire intervals (2, 4, and 10 years), while analyzing differences among species and stump sizes. The results showed that root sprouts were the dominant regeneration mechanism, accounting for over 90% of post-fire sprouting and underscoring the importance of below-ground bud banks. Sprout density peaked two years after the fire and gradually declined thereafter, indicating a decrease in sprouting potential as the stands aged. Despite similar sprouting responses among species, likely due to shared physiological traits such as extensive root systems, variations in sprout density and growth were observed across different stands. A significant negative correlation was found between stump diameter and both sprout number and growth rates, with small to medium-sized stumps (5–35 cm) showing the highest sprouting potential. Rapid sprout growth occurred within the first two years post-fire, often surpassing mature tree growth rates, likely due to established root systems and enhanced nutrient availability. The study concluded that sprouting is vital for oak regeneration in fire-prone areas, especially where seed-based regeneration is limited. It supports coppice management strategies, including thinning and stump management, to encourage vigorous sprout growth. Recommendations include cutting burned trees (diameter > 5 cm) during the dormant season, restricting grazing for 4–5 years, and thinning sprouts to enhance post-fire regeneration and ensure the long-term sustainability of these valuable oak forests.