Pasquale Antonio Marziliano

Wildfires are a major ecological disturbance in Mediterranean forests, whose frequency and intensity are increasingly driven by climate change and land-use dynamics. This study investigated post-fire natural regeneration and soil properties in Aleppo pine stands seven years after a high-severity crown fire in southern Italy. Two stand types—pure pine and mixed pine—were compared, differing in fire severity and structural composition. We evaluated seedling density and dendrometric parameters (height and collar diameter), as well as soil parameters (pH, organic matter, and bulk density) to assess their role in post-fire recovery. Regeneration was abundant and composed exclusively of Aleppo pine, with significantly higher seedling density in the pure pine stand, where fire severity was greatest. In mixed pine stand, moderate fire severity combined with interspecific competition limited regeneration density. Deadwood presence enhanced microclimatic conditions favorable to seedling establishment, supporting a post-fire recovery dynamic consistent with self-succession, whereby pre-fire dominant species are favored. Soil analyses revealed higher organic matter content and lower bulk density in the pure stand, which likely facilitated regeneration. Overall, these findings underscore the ecological value of deadwood retention and passive management strategies in fostering spontaneous forest recovery. A better understanding of post-fire regeneration patterns and soil conditions can inform adaptive management approaches to strengthen forest resilience in Mediterranean forests under increasing climate pressure.

Wildfires represent a major ecological disturbance in Mediterranean forests, increasingly intensified by climate change and land-use changes. This study investigated post-fire natural regeneration and soil properties in Aleppo pine stands seven years after a high-severity crown fire in southern Italy. The analysis compared two stand types: pure pine and mixed pine stands, differing in fire severity and structural composition. We assessed seedling density, spatial distribution, and dendrometric parameters (height and collar diameter), and evaluated soil parameters (pH, organic matter, and bulk density) to understand their influence on post-fire recovery. Results showed abundant regeneration composed exclusively of Aleppo pine, with significantly higher seedling density in the pure pine stand, where fire severity was greatest. In mixed pine stand, moderate fire severity and interspecific competition reduced regeneration density. The presence of deadwood was found to enhance microclimatic conditions conducive to seedling establishment and the post-fire recovery in Mediterranean pine forests follows a model of self-succession, favouring pre-fire species. Soil analyses revealed higher organic matter content and lower bulk density in the pure stand, which may have supported regeneration. These findings highlight the importance of deadwood retention and passive management strategies in promoting spontaneous forest recovery. Understanding post-fire regeneration patterns and soil conditions can inform adaptive management policies to enhance forest resilience in Mediterranean ecosystems under climate pressure.

In the Mediterranean basin, coniferous reforestation mainly comprises forest stands highly susceptible to fires. When silvicultural treatments have not been performed for decades after plantation, these stands often exhibit high vertical and horizontal tree density, along with a significant occurrence of lying and standing deadwood, thereby increasing the fuel load. On average, these pine forests are characterized by high values of above-ground biomass, ranging from 175 to 254 Mg ha⁻¹ for the younger and the older ones, respectively. The theoretical heat energy produced per surface unit, in the case of the total combustion of the above-ground biomass, is also high, varying from 300 to 450 MJ ha⁻¹ depending on the stage of stand development. In this study, we demonstrated the importance of silvicultural interventions in reducing the pyrological potential in pine reforested stands located in southern Italy, also giving attention to the water savings needed during extinction phases. In detail, we applied a preliminary mathematical reaction-diffusion model aimed at predicting the development of forest fires. The model was applied using data obtained through the estimation of the pyrological potential in terms of heat energy produced per surface unit (1 hectare) and the variation in the critical surface intensity. We verified that, when silvicultural interventions are applied, they induce a reduction of heat energy ranging between 17 and 21%, while the extinguishing water saved ranges between 600 and 1000 Mg ha⁻¹. Moreover, when the silvicultural interventions are implemented, the probability of the transition from surface fire to crown fire can be reduced by up to 31%. The most effective results on fire risk mitigation are mainly obtained when thinning aimed at reducing canopy and tree density is carried out in the younger phases of the reforested pine stands.

The easy implementation of a nature-based solution (NBS) to address a prompt stabilisation of burnt areas may be crucial in the Mediterranean forest environment. A plot scale hydrological and ecological survey was conducted in a pine forest of the Aspromonte Massif (southern Italy) affected by a high fire severity in summer 2021. The hydrological response to 30 rainfall event groups is analysed by monitoring nine sloping plots distributed into three plot blocks (forested according to the pre-fire situation, burnt with randomly directed felled logs and burnt with manually felled logs redirected along contour lines). The hydrological response of bare soil is mitigated by about 30% through the combined effects of the NBS and the vegetation cover by pioneer species. Although the regeneration of Pinus radiata is scarcer in the arranged plots, the spontaneous vegetation, once gone, prepares better edaphic conditions for the triggering of forest dynamics assured by the auto-succession of Pinus radiata. In terms of woody mechanical resistance, NBS durability is compatible with the time required for seedlings to regenerate the forest ecosystem. The results achieved so far encourage further research on higher slopes and complementary aspects (vegetal and animal biodiversity, economic factors, etc.).

Trade-offs between high stand productivity and good wood quality exist for chestnut coppices and related wood-based products. The main objective of this study was to determine the most suitable duration (in years) of cutting cycles that maximizes stand productivity and preserve wood quality of chestnut coppices in a Mediterranean setting. To this aim, a stand-level growth model was developed to verify if wood quality of chestnut coppices at different stand ages varies when the rotation period is modified. Wood quality and stand productivity were analysed, using a chronosequence approach, in coppice stands in Southern Italy characterized by four cutting cycles (15, 25, 30, and 50 years). Results implied that the culmination of the mean annual increment occurs at 28 years, while the current annual increment culminates 10 years earlier. The MOEd values revealed a negative correlation with shoot age; however, a cutting cycle between 25 and 30 years might represent the best compromise for balancing stand productivity and wood quality. Results are discussed in the context of adaptive forest management.

Trade-offs between high stand productivity and good wood quality exist for chestnut coppices and related wood-based products. The main objective of this study was to determine the most suitable duration (in years) of cutting cycles to maximize stand productivity and preserve wood quality. To this aim, a growth model was developed to verify if wood quality of chestnut coppices at different stand ages varies when the rotation period is modified. Wood quality and stand productivity were analysed, using a chronosequence approach, in stands characterized by four cutting cycles (15, 25, 30, and 50 years). Results implied that the culmination of the mean annual increment occurs at 28 years, while the current annual increment culminates 10 years earlier. The MOEd values revealed a negative correlation with shoot age, however, a cutting cycle between 25 and 30 years might represent the best compromise for balancing stand productivity and wood quality.

The present study was focused on how cardinal directions inside gaps of different sizes (small, 200 m²; medium, 400 m²; and large, 600 m²) can affect soil characteristics and tree regeneration. Additionally, the effects of gap size on the growth dynamics of trees outside the gaps were evaluated. The study was carried out in a European beech stand located in Aspromonte National Park (Southern Apennines, Calabria, Italy). Microclimatic variables, physical, chemical, and biochemical soil properties, natural regeneration density, and growth trees outside the gaps density of natural regeneration were assessed. This study provided evidence for an important effect of cardinal points on micro-environmental parameter variability, nutrient cycle, physic-chemical soil properties, water availability, and biological processes such as trees growth and regeneration. The European beech natural regeneration was most abundant in the south part of the gaps. Thus, we can state that cardinal points affect the trees natural regeneration in a species-specific manner. The new microclimatic conditions due to the gap opening had positive effects on the tree growth located along the gap edge, especially in the trees sampled on the edges of the medium gaps. On the contrary, the trees located in the forest recorded a productivity coherent with the period prior the gap opening. In medium-sized gaps, the combination and interaction of microclimatic and soil parameters (humification and mineralization process and microbial activity) created the best conditions for beech natural regeneration and favored an increase in the productivity of the trees at the edge of the gaps.