Post-Fire Sprouting Dynamics of Quercus brantii Lindl.: Assessing Stem Size Influence and Adaptive Responses to Recurrent Fires

Aims: Persian oak (Quercus brantii) relies heavily on sprouting for post-fire persistence. However, the long-term influence of initial stem size and the impact of repeated fires on these sprouting dynamics require clarification. This study aims to (۱) quantify the effect of initial stem size on sprout characteristics (number, diameter, height) over several years following a fire and (۲) compare these regeneration responses after an initial versus a recurrent fire. This study offers novel insights by examining the dynamics of Persian oak regeneration over several years and across two fire events. Materials & Methods: Post-fire regeneration of Persian oak was monitored in the Zagros forests, Iran. The study was conducted in the Berjue Protected Area. A total of ۷۶ Persian oak trees were surveyed for four years after a ۲۰۱۹ fire. Sprout number, diameter, and height were measured annually. After a second fire in the fifth year, ۱۸ surviving trees were re-evaluated. Sprouting trends were analyzed using ANCOVA and regression models. A Combined Growth Index (CGI) was developed to assess overall sprout performance. Findings: Sprouting declined over time, with the number of sprouts per stem decreasing by more than ۵۰% in trees with fewer than three initial stems. Initial stem size significantly influenced long-term regeneration (P<۰.۰۱). Trees with ۷–۹ initial stems showed the most remarkable diameter growth (up to ۰.۹ cm.y-۱), while the tallest sprouts (averaging ۱۷۰ cm) were found in trees with fewer stems. Following the second fire, the mean sprout count dropped from ۹.۶ to ۵.۱ per stem, indicating reduced regeneration capacity. However, sprout diameter, height, and CGI showed no significant decline, suggesting sustained growth performance despite recurrent fire exposure. Conclusion: The initial number of stems, competition, and resource allocation determines the sprouting pattern. To support oak regeneration and ecosystem resilience, managers should implement selective thinning to reduce intra-stem competition and use low-intensity prescribed burns to minimize damage while promoting sprouting in fire-adapted individuals. It is essential to avoid recurring fires at short time intervals to allow adequate recovery time, preventing severe regeneration decline.

کلیدواژه ها:

Sprouting dynamics ، Stem size influence ، Oak forest resilience ، Fire ecology ، Coppice regeneration