Post-fire tree mortality and regeneration in Pinus canariensis stands under different forest treatments

Fire is a fundamental natural disturbance shaping forest dynamics, yet climate change and human activities are altering fire regimes in ways that may compromise forest resilience and recruitment. The two key species in structuring Canary pine forests exhibit contrasting fire adaptations and regeneration strategies. The paleoendemic Canary pine ( Pinus canariensis ) possesses a remarkable combination of fire-related traits, including exceptionally thick bark, the rather rare ability among conifers to resprout epicormically after complete crown combustion, and low to intermediate serotiny. On the other hand, the Canary tree heath ( Erica canariensis ), endemic to the Canary Islands and Madeira, is a typical basal resprouter in Canary pine forests. Quantitative evidence, especially assessing individual tree characteristics, supporting the combination of traits related to each strategy remains limited. This study examined post-fire mortality and regeneration of P. canariensis and E. canariensis , both at the individual tree and the stand level, following the 2023 Tenerife wildfire, comparing semi-natural stands, dense reforested plantations, and thinned plantations. Post-fire mortality of adult pines was low (16.5%) and strongly decreased with increasing stem diameter at breast height (DBH). Burned trees exceeding 30 cm DBH showed very high survival, even after complete crown combustion. Mortality was also influenced by intraspecific competition, forest treatment, and summer rainfall. In contrast, juvenile pines experienced 80% mortality, highlighting a potential risk to long-term stand regeneration, as recurrent fires may eliminate regeneration cohorts before they reach fire-resistant sizes and reproductive maturity. Post-fire tree mortality of E. canariensis reached 26.5%, with surviving individuals recovering through basal resprouting. Both survival and resprouting vigor of this species increased with pre-fire tree height. Fire strongly influenced Canary pine seedling density, exhibiting a unimodal relationship with fire severity that peaked at 50–70% crown damage. Post-fire pine seedling height was positively related to fire severity and summer precipitation. These findings, interpreted within a mixed-fire regime and evolutionary framework, highlight the fire adaptation and resilience of tree species in humid Canary pine forest. Nevertheless, increasing fire frequency could threaten long-term ecosystem persistence, emphasizing the need to conserve old-growth forest structures and define fire-return intervals that sustain regeneration under ongoing global change.