Post-fire restoration with contour-felled log debris increases early recruitment of Spanish black pine (Pinus nigra Arn. ssp. salzmannii) in Mediterranean forests

Post-fire environmental conditions can heavily influence the natural regeneration of pine species in Mediterranean forests. Therefore, enhancing post-fire recovery of pine species is fundamental for effective ecological restoration of Mediterranean forests. In this study, the effects of a post-fire restoration treatment on the seedling emergence and survival of Spanish black pine (Pinus nigra Arn. ssp. salzmannii) were investigated under a treatment consisting of manual cut of burnt tree canopies placed on the soil surface with their tree branches, following contour lines (contour-felled log debris, CFD) in comparison with a control site at plot scale. Both CFD and control plots were tested on three slope gradients and two experimental conditions, that is, protected vs. non-protected seeds. The initial seedling recruitment of Spanish black pine was improved by CFD treatment and seed protection, specifically through increased survival of emergent seedlings by about 10 and 15 times, respectively, compared to control. Seedling emergence was not significantly different between the treatments or controls; however, the highest seedling emergence in the study (18.9 ± 14.9%) was recorded under the least severe drought conditions. The study demonstrates that post-fire CFD and seed protection treatments can be favorable for supporting ecological restoration of these pine forests. However, the environmental conditions are important drivers for the success of these strategies. Since droughts are expected to be more frequent in the upcoming years, post-fire management strategies that include treatments like CFD and seed protection can be useful in the ecological restoration of Mediterranean pine forests.