Raffaella Lovreglio

Anatomic basis and insulation of serotinous cones in Pinus halepensis Mill

Pinus halepensis Mill., a widespread, low elevation conifer common in Mediterranean Basin, shows a dual reproductive strategy: post-fire obligate seeder (from serotinous cones) and an early coloniser (from non-serotinous cones). Release of seeds encased in serotinous cones is induced either by fire (pyriscence, serotiny or bradychory) or by drying (xeriscence). Morphological differences in serotinous and non-serotinous cones in natural populations of P. halepensis in Southeastern Italy were analyzed. Relationships between tree size (diameter class) and serotiny were checked by counting and sampling serotinous and non-serotinous cones. The macro and microscopic characteristics that could affect cones’ opening were measured in sampled cones. Protection against high temperatures offered by wood scales was also evaluated by applying different temperatures and time exposures, and following the inner thermal raise. Results showed that non-serotinous cones had bigger resin ducts and more separate scales. Also it was highlighted that ovuliferous scales of serotinous cones were bigger and thicker. These scales had more lamellated (multilayered) sclereid cells, and were significantly thinner with a shorter lumen diameter. Continuous temperature-monitoring heat tests inside cones showed that temperatures close to the cone axis were rather low, so seed germination was not influenced. Results confirm that serotinous cones are more compact, rigid and consistent than non-serotinous cones. These characteristics explain the lower insulation, seed protection and the ease opening of non-serotinous cones as well. In conclusion, opening mechanism of pinecone scales under the effect of fire or dry conditions seem related to anatomic differences and it provides seeds with an efficient protection against heat.

Morphological and anatomical differences in Aleppo pine seeds from serotinous and non-serotinous cones

Mediterranean communities have been historically conditioned by fire and have therefore developed adaptive traits. Serotiny is a strategy that increases fire resilience by storing seeds in the canopy, protecting them from heat and delaying their dispersion. Aleppo pine is an important serotinous tree species in the low altitude, near-coastal Mediterranean Basin. Differences in serotinous and non-serotinous cones have been detected previously but in order to resolve a gap in the knowledge on seed adaptation to fire, we focused this study on two fire-prone habitats in southern Italy. Several cones were sampled and opened in an oven at two different temperatures in order to group seeds according to provenance and cone type (serotinous or non-serotinous). The sampled seeds were weighed and their coats were removed. Seed size, embryo diameter and nutritive tissue thickness were recorded. We found that seeds with greater weight and size came from the more humid site and from non-serotinous cones. Also, we observed wax and cutine cells formed a thicker seed coat in seeds from the more humid site using a scanning electron microscope. The scanning electron microscopy/energy dispersive X-ray spectroscopy showed higher Si and Ca concentrations in the covers of serotinous seeds. Seeds from different provenance and cone types have anatomic and morphological differences that confer different properties against heating. This knowledge can improve post-fire management and promote restoration tools.

Developing custom fire behavior fuel models for Mediterranean wildland–urban interfaces in southern Italy

The dramatic increase of fire hazard in wildland–urban interfaces (WUIs) has required more detailed fuel management programs to preserve ecosystem functions and human settlements. Designing effective fuel treatment strategies allows to achieve goals such as resilient landscapes, fire-adapted communities, and ecosystem response. Therefore, obtaining background information on forest fuel parameters and fuel accumulation patterns has become an important first step in planning fuel management interventions. Site-specific fuel inventory data enhance the accuracy of fuel management planning and help forest managers in fuel management decision-making. We have customized four fuel models for WUIs in southern Italy, starting from forest classes of land-cover use and adopting a hierarchical clustering approach. Furthermore, we provide a prediction of the potential fire behavior of our customized fuel models using FlamMap 5 under different weather conditions. The results suggest that fuel model IIIP (Mediterranean maquis) has the most severe fire potential for the 95th percentile weather conditions and the least severe potential fire behavior for the 85th percentile weather conditions. This study shows that it is possible to create customized fuel models directly from fuel inventory data. This achievement has broad implications for land managers, particularly forest managers of the Mediterranean landscape, an ecosystem that is susceptible not only to wildfires but also to the increasing human population and man-made infrastructures.

APPLICAZIONE DEL METODO DELPHI PER L'ANALISI DELLE MOTIVAZIONI DEGLI INCENDI: IL CASO TARANTO ( 1 )

Il crescente numero di incendi richiede una organizzazione difensiva piu attenta alla prevenzione, affidando un ruolo fondamentale agli strumenti di indagine territoriale, che possono aiutare ad individuare linee di tendenza e concentrazione del fenomeno, a interpretarne la dinamica e le motivazioni e ad impostare efficaci azioni di previsione del rischio. Fondamentale appare l’impiego di tecniche di investigazione che consentono di definire la distribuzione spaziale degli eventi sul territorio, agevolando l’interpretazione di un fenomeno di origine prevalentemente antropica con l’aiuto della conoscenza del problema a livello locale e dell’esperienza degli operatori del settore AIB. Il lavoro affronta aspetti relativi alla distribuzione del fenomeno attraverso il metodo della kernel density e all’applicazione del metodo Delphi per la valutazione delle motivazioni. L’applicazione delle due metodologie di analisi in ambito provinciale ha permesso l’identificazione delle motivazioni principalmente di origine volontaria (ampliamento, apertura o rinnovazione del pascolo a spese del bosco) e involontaria (attivita di ripulitura di incolti, bruciature stoppie, attivita di miglioramento o rinnovazione del pascolo).

Management of Threatened, High Conservation Value, Forest Hotspots Under Changing Fire Regimes

The current chapter starts by describing the elements of biodiversity in the Mediterranean Basin hotspot. It then describes climate change and fire regime interactions. Geographically restricted forest types with high conservation value such as Abies cephalonica, A. pinsapo, Juniperus macrocarpa, Quercus trojana, Tetraclinis articulata and Pinus leucodermis forests are presented as case studies. These forest hotspots are threatened by changing fire regime either because they lack of any active post-fire regeneration mechanism or because they are exposed to more frequent fires than they used to. Current post-fire management, if any, is presented and commented.