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One of the suggested management options for reducing fire danger is the selection of less flammable plant species. Nevertheless, vegetation flammability is both complex and dynamic, making identification of such species challenging. While large efforts have been made to connect plant traits to fire behavior, seasonal changes and within species variability of traits are often neglected. Currently, even the most sophisticated fire danger systems presume that intrinsic characteristics of leaf litter stay unchanged, and plant species flammability lists are often transferred from one area to another. In order to assess if these practices can be improved, we performed a study examining the relationship between morphological characteristics and flammability parameters of leaf litter, thereby taking into account seasonal and local variability. Litter from six Mediterranean tree species was sampled throughout the fire season from three different locations along a climate gradient. Samples were subjected to flammability testing involving an epiradiator operated at 400 °C surface temperature with 3 g sample weight. Specific leaf area, fuel moisture content, average area, and average mass of a single particle had significant influences on flammability parameters. Effects of sampling time and location were significant as well. Due to the standardized testing conditions, these effects could be attributed to changes in intrinsic characteristics of the material. As the aforementioned effects were inconsistent and species specific, these results may potentially limit the generalization of species flammability rankings. Further research is necessary in order to evaluate the importance of our findings for fire danger modeling.

In the recent decades changes in fire regimes led to higher vulnerability of fire prone ecosystems, with vegetation being the only component influencing fire regime which can be managed in order to reduce probability of extreme fire events. For these management practices to be effective reliable information on the vegetation flammability is being crucial. Epiradiator based testing methods are one of the methods commonly used to investigate vegetation flammability and decrease in ignition frequency is always interpreted as a decrease in flammability. Furthermore, gathered information is often combined into a single flammability score. Here we present results of leaf litter testing which, together with previously conducted research on similar materials, show that material with very low ignition frequency under certain testing conditions can be extremely flammable if testing conditions are slightly changed. Additionally, our results indicate that combining measured information into one single flammability score, even though sometimes useful, is not always meaningful and should be performed with caution.

The paper investigates the ameliorative properties of pine cultures in their site conditions on the island of Rab. Pines, as allochthonous and pioneer species, were used to afforest degraded and devastated areas on the island because of their important role in the process of progressive vegetation succession. Twelve sample plots were established in the forest pine cultures. They encompassed various pine cultures (maritime pine, Aleppo pine and black pine) in diverse parent substrates (limestone, reddish-brown quartz sand, Flysch) and different soil types (eutric cambisol, cambisol on limestone, red soil and rendzina). To process the data, the following multivariate analyses were used: Two Way Indicator Species Analysis (TWINSPAN), Canonical Correspondence Analysis (CCA) and Indicator Species Analysis. The research results showed differences among the forest cultures of black pine, Aleppo pine and maritime pine. A relationship was found between the quantitative environmental variables (slope, pH, humus, the C/N ratio, age and the quantity of leaf litter) and the vegetation. As well as the relationship of the species towards qualitative variables (type of pine culture, parent substrate, soil type, exposition).

Osim što ugrožavaju proizvodnju šumske biomase, požari mogu poremetiti i ekološku ravnotežu te narušiti trajno održivi razvoj. Uz to mogu imati i tragičnije posljedice kao što je to bilo na Kornatima u ljeto 2007. godine. U vezi s tim obavljena su istraživanja vegetacije i testiranje njene zapaljivosti i gorivosti. Testiranje zapaljivosti obavljeno je u laboratoriju u Makarskoj prema metodologiji koju je opisao Valette (1990). Samim uzorkovanjem na terenu odmah je uočeno da grmlje nije izgoreno, odnosno drvenasti dijelovi vegetacije debljine iznad 5 mm ostali su vitalni i živi. Suhi dijelovi travne vegetacije koji su zaklonjeni kamenom ostali su također neizgoreni. Iz rezultata testiranja vidljivo je da je vegetacija bila krajnje zapaljiva. Travna vegetacija imala je sadržaj vlage od 10 do 16 %, a vrijeme zapaljenja je bilo 2 s. Kod drvenaste vegetacije vrijeme zapaljenja kretalo se od 18 do 22 s, dok je sadržaj vlage bio od 13 do 53 %. Pokrovnost vegetacijom kretala se od 3425 kg/ha do 4948 kg/ha kod travne vegetacije i od 2180 kg/ha do 3425 kg/ha kod drvenaste vegetacije., Apart from endangering the production of forest biomass, fires may also disturb the ecological balance and disrupt permanent sustainable development. However, fires may have even more tragic consequences, as it was in the case of Kornati in the summer of 2007. Vegetation was investigated and its ignitability and flammability were tested. Ignitability was tested in the laboratory in Makarska using the methodology described by Valette (1990). Field sampling revealed that the shrubs were not burnt and that woody vegetation parts exceeding 5 mm in thickness remained vital and alive. The dry parts of grass vegetation sheltered by stones were also unaffected. Test results showed that the vegetation was extremely flammable. The humidity content of grass vegetation ranged from 10 to 16 % and the ignition time was 2 s. In woody vegetation the ignition time oscillated from 18 to 22 s, with humidity ranging from 13 to 53 %. Vegetation cover ranged from 3,425 kg/ha to 4,948 kg/ha in grass vegetation and from 2,180 kg/ha to 3,425 kg/ha in woody vegetation.

In this paper, we investigate the natural regeneration of Aleppo pine stand after forest fire. A permanent experimental plot was established on a burnt area in 2001 (forest fire in 1999), and the dynamics of the natural regeneration was monitored during five years (2001-2005). The appearance of young growth was monitored by species composition, abundance and height classes of the plants. The impact of the intervention works after fire was also evaluated. Soil samples from the experimental plot were analyzed to establish chemical and mechanical properties of the soil. Results suggest natural, aggressive, almost weed-like spread and regeneration of Aleppo pine plants over the burnt area. Six years after the forest fire the young plants of Aleppo pine with their height had overgrown the burnt material and with 103 563 plants per ha (10.3 plants/m2) completely covered the burnt area. This experiment implies the need for different way of intervention works after the forest fires in the Aleppo pine stands. Unnecessary and expensive gathering of burnt material into the strips should be avoided. Strips of burnt material formed in this way are very slowly decomposing given the climatic conditions of the Mediterranean area. Moreover, they contribute to the constant danger of forest fire and degrade the landscape aesthetically. The suggested way for sanation of burnt areas is chipping of burnt material with chain saw, and laying it on the ground. Soil moisture and microclimatic conditions of the young Aleppo pine stand will accelerate the development of micro-organisms, decomposition of the burnt material and the process of humification. The Aleppo pine, as a pioneering tree species in the eu-Mediterranean area, has an important and irreplaceable role in restoring devastated green areas, as well as in the preparation of site conditions for the accession of autochthonous vegetation and the basic species for this region, which is the Holm oak.