ABSTRACT:The Fire Weather Index module of the Canadian Forest Fire Danger Rating System (CFFDRS) was evaluated during two consecutive fire seasons in the Mediterranean environment of Crete, Greece. The Duff Moisture Code (DMC), the Drought Code (DC), the Buildup Index (BUI) and the Fire Weather Index (FWI) were highly correlated to fire occurrence but only moderately to area burned. Logistic regression was applied in order to classify the FWI values into fire danger classes appropriate for the Mediterranean environments, as follows: 0-38 Low, 39-48 Moderate, 49-59 High, >60 Extreme. The new classification was necessary because the existing Canadian fire danger classes were found inapt for the dry and extremely fire prone eastern Mediterranean climate of Crete. After the modification, the fluctuation of the FWI values predicted more successfully the days of high fire risk, as proved by the actual fire occurrence. High correlation was found between measured litter (L layer) moisture values and those predicted by the Fine Fuel Moisture Code (FFMC). The use of an equilibrium duff moisture content value lower than 20% in Mediterranean environments, would probably improve the Duff Moisture Code (DMC) predictions. The Drought Code (DC) was poorly correlated to the upper soil moisture content. Overall, the FWI demonstrated several aptitudes related to its potential use as a meteorological fire danger rating index in Mediterranean regions. However, long-term studies are necessary to determine the precise range of each fire danger class according to fire occurrence data.

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-Canopy fuel characteristics that influence the initiation and spread of crown fires were measured in representative Aleppo pine (Pinus halepensis Mill.) stands in Greece. Vertical distribution profiles of canopy fuel load, canopy base height and canopy bulk density are presented. Aleppo pine canopy fuels are characterized by low canopy base height (3.0−6.5 m), while available canopy fuel load (0.96−1.80 kg/m 2 ) and canopy bulk density (0.09−0.22 kg/m 3 ) values are similar to other conifers worldwide. Crown fire behavior (probability of crown fire initiation, crown fire type, rate of spread, fireline intensity and flame length) in Aleppo pine stands with various understory fuel types was simulated with the most updated crown fire models. The probability of crown fire initiation was high even under moderate burning conditions, mainly due to the low canopy base height and the heavy surface fuel load. Passive crown fires resulted mostly in uneven aged stands, while even aged stands gave high intensity active crown fires. Assessment of canopy fuel characteristics and potential crown fire behavior can be useful in fuel management and fire suppression planning.canopy fuels / crown fires / fire behavior / Aleppo pine (Pinus halepensis Mill.) / Mediterranean Basin Résumé -Caractéristiques des combustibles de la canopée et comportement du potentiel de feu des couronnes de forêts de Pin d'Alep (Pinus halepensis Mill.). Les caractéristiques des combustibles qui influencent le démarrage et la propagation des feux de couronnes ont été mesurées dans des peuplements représentatifs de Pinus halepensis Mill. en Grèce. Des profils verticaux de la charge en combustible de la canopée, la hauteur de la base de la canopée et la densité volumique de la canopée sont présentés. La charge combustible de la canopée est caractérisée par une faible hauteur de la base de la canopée (3,0−6,5 m), tandis que la charge en combustible disponible (0,96−1,80 kg/m 2 ) et la densité volumique de la canopée (0,09−0,22 kg/m 3 ) sont similaires à celles des autres conifères dans le monde. Le comportement du feu de couronne (probabilité de démarrage du feu dans les couronnes, type de feu de couronne, taux de propagation, intensité de la ligne de feu et longueur des flammes) dans les peuplements de Pinus halepensis avec différents types de combustibles de sous-bois a été simulé avec le maximum de modèles actuels de feux de couronnes. La probabilité de démarrage de feu de couronne était forte même en conditions de faible embrasement, principalement en relation avec la faible hauteur de la base des couronnes et la forte charge en combustible au sol. Des feux passifs de couronnes se produisent principalement dans les peuplements inéquiennes tandis que les peuplements équiennes ont présenté de fortes intensités de feux actifs de couronnes. L'évaluation des caractéristiques des combustibles de la canopée et le comportement du potentiel de feu peuvent être très utiles pour la gestion des combustibles et la planification de la lutte contre les feux. c...

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The first large-scale network of 79 tree-ring chronologies in the Eastern Mediterranean and Near East (EMNE; 33°N–42°N, 21°E–43°E) is described and analyzed to identify the seasonal climatic signal in indices of annual ring width. Correlation analysis and cluster analysis are applied to tree-ring data and gridded climate data to assess the climate signal embedded in the network in preparation for climate field reconstructions and formal proxy/model intercomparison experiments. The lengths of the 79 combined chronologies range from 89 to 990 years. The monthly correlations and partial correlations reveal a pervasive positive association with May, June, and sometimes July precipitation, positive correlations with winter and spring (December through April) temperatures, and negative relationships with May through July temperature, although as expected, there are site-to-site exceptions to these general patterns. Cluster analysis suggests three groups of sites based on their association with climate. The chronologies for the EMNE have coherent seasonal precipitation and temperature signals across a fairly broad geographical domain. The predominant signal is a positive growth response to May–June precipitation. Collectively, the findings suggest that the network can be exploited to develop season-specific field reconstructions of precipitation and drought history in the EMNE.