Ioannis Mitsopoulos

Canopy fuel characteristics and potential crown fire behavior in Aleppo pine (Pinus halepensis Mill.) forests

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/m2) and canopy bulk density (0.09–0.22 kg/m3) 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.RésuméLes 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/m2) et la densité volumique de la canopée (0,09–0,22 kg/m3) 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.

Assessing ignition probability and moisture of extinction in a Mediterranean grass fuel

The objective of this study was the assessment of the probability of ignition and moisture of extinction of the annual herbaceous species Slender Oat (Avena barbata Pott. ex Link) in Greece. Multiple ignition tests were conducted in situ with a drip torch during two fire seasons, with simultaneous monitoring of the weather conditions. Stepwise logistic regression was applied to assess the probability of ignition based on plant moisture content and meteorological parameters. Fuel moisture content was determined to be the only statistically significant (P 30% ODW) fuel moisture contents. Assessment of the ignition potential and moisture of extinction of grass fuels is a prerequisite for reliable fire danger prediction.

Spatial patterns of eastern Mediterranean climate influence on tree growth

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.

Wildfire Risk Assessment in a Typical Mediterranean Wildland–Urban Interface of Greece

The purpose of this study was to assess spatial wildfire risk in a typical Mediterranean wildland–urban interface (WUI) in Greece and the potential effect of three different burning condition scenarios on the following four major wildfire risk components: burn probability, conditional flame length, fire size, and source–sink ratio. We applied the Minimum Travel Time fire simulation algorithm using the FlamMap and ArcFuels tools to characterize the potential response of the wildfire risk to a range of different burning scenarios. We created site-specific fuel models of the study area by measuring the field fuel parameters in representative natural fuel complexes, and we determined the spatial extent of the different fuel types and residential structures in the study area using photointerpretation procedures of large scale natural color orthophotographs. The results included simulated spatially explicit fire risk components along with wildfire risk exposure analysis and the expected net value change. Statistical significance differences in simulation outputs between the scenarios were obtained using Tukey’s significance test. The results of this study provide valuable information for decision support systems for short-term predictions of wildfire risk potential and inform wildland fire management of typical WUI areas in Greece.

Local-Scale Fuel-Type Mapping and Fire Behavior Prediction by Employing High-Resolution Satellite Imagery

Judicial wildland fire prevention and management requires precise information on fuel characteristics and spatial distribution of the various vegetation types present in an area. The aim of this study was to present an integrated approach to forest fire management, combining local-scale fuel-type mapping from very high spatial resolution imagery with fire behavior simulation. The specific objectives were (i) to develop a detail site-specific fuel model in a Mediterranean area that is suitable for fire behavior prediction; (ii) to produce a detailed local-scale fuel-type map with an object-based approach; and (iii) to generate accurate fire behavior maps. The spatial extent of the different fuel types of a forested landscape in northern Greece characterized by heterogeneous vegetation and topography was determined using a Quickbird image. Site-specific fuel models were created by measuring fuel parameters in representative natural fuel complexes. Following necessary preprocessing of the image to compensate for geometric errors, multiscale components of the scene were delineated through a segmentation algorithm. The resulting image objects were assigned to respective fuel types using a CART statistical model with an overall accuracy over 80%. The FARSITE fire simulation model was applied to simulate potential wildland fire growth and behavior. Utilizing the spatial database capabilities of geographic information systems, FARSITE allows the user to simulate the spatial and temporal spread and behavior of a fire burning in heterogeneous terrain, fuels, and weather.

Fire History In European Black Pine (Pinus nigra Arn.) Forests of the Valia Kalda, Pindus Mountains, Greece

Abstract The past fire regime of European black pine (Pinus nigra Arn.) forests in Valia Kalda in Greece was investigated by standard dendrochronology methods. The sampled trees contained a record of fires from the early 14th Century through the late 19th Century with the last fire recorded in 1891. Evidence of non-lethal surface fires over the past seven centuries suggests that in addition to its destructive power, fire also plays a role in ecological functioning of the region. This is the first fire history study in Greece and can provide a basis for development of the first fire history network in the region. It also provides insight and perspective that may be useful for planning and justifying future ecosystem management programs.

Allometric equations for crown fuel biomass of Aleppo pine (Pinus halepensis Mill.) in Greece

Allometric equations for the estimation of crown fuel weight of Aleppo pine (Pinus halepensis Mill.) trees in the Mediterranean Basin were developed. Forty trees were destructively sampled and their crown fuels were weighed separately for each fuel category. Crown fuel components, both living and dead, were separated into size classes and regression equations that estimate crown fuel load by diameter class were derived. The allometric equation y = ax b with diameter at breast height as the single predictor was chosen, because the addition of other parameters did not decrease the residual sum of squares significantly. The adjusted coefficient of determination (R 2 ) values were high (R 2 = 0.82-0.88) in all cases. Diameter at breast height was the most significant determinant of crown fuel biomass. The aerial fuels that are consumed during crown fires (i.e. needles and twigs with diameter less than 0.63 cm) comprised 29.3% of the total crown weight. Live fuels constituted ∼96.3% of total crown biomass, distributed as follows: needles 16.7% (average load 12.07 kg), branches with 0.0-0.63-cm diameter 12.6% (average load 9.18 kg), 0.64-2.5-cm diameter 37.3% (27.99 kg), 2.51-7.5-cm diameter 25.4% (18.59 kg), and >7.5-cm diameter 3.7% (2.65 kg). The equations provide quantitative fuel biomass attributes for use in crown fire behaviour models, fire management and carbon assessment in Aleppo pine stands. Additional keyword: crown fires.

Predicting wildfire spread and behaviour in Mediterranean landscapes

The use of spatially explicit fire spread models to assess fire propagation and behaviour has several applications for fire management and research. We used the FARSITE simulator to predict the spread of a set of wildfires that occurred along an east–west gradient of the Euro-Mediterranean countries. The main purpose of this work was to evaluate the overall accuracy of the simulator and to quantify the effects of standard vs custom fuel models on fire simulation performance. We also analysed the effects of different fuel models and slope classes on the accuracy of FARSITE predictions. To run the simulations, several input layers describing each study area were acquired, and their effect on simulation outputs was analysed. Site-specific fuel models and canopy inputs were derived either from existing vegetation information and field sampling or through remote-sensing data. The custom fuel models produced an increase in simulation accuracy, and results were nearly unequivocal for all the case studies examined. We suggest that spatially explicit fire spread simulators and custom fuel models specifically developed for the heterogeneous landscapes of Mediterranean ecosystems can help improve fire hazard mapping and optimise fuel management practices across the Euro-Mediterranean region.

Elevation-layered dendroclimatic signal in eastern Mediterranean tree rings

The authors wish to thank the Forestry Departments in Turkey, Greece, Cyprus, Lebanon, and Syria for their great help and support in making this study possible. We would like to thank the Cyprus Meteorological Service for providing us with climate data. We thank Professor Alexandros P Dimitrakopoulos, of the Laboratory of Forest Protection, School of Forestry and Natural Environment, Aristotle University of Thessaloniki, Greece, for his help and support. We thank Christopher Baisan, Russell Biggs, and Gurudas C Bock for their valuable assistance in the field. We also thank Russell Biggs, Victoria L Frazier, Alicia Stout, Gurudas C Bock, Jessica L Little, and Anthony P Trujillo for their assistance in sample preparation and measurement. We wish to thank the anonymous reviewers for their constructive comments and suggestions on the manuscript. Funding was provided by the US National Science Foundation under Grant Earth System History (Grant No. 0075956), ATM-GEO/ATM-Paleoclimate Program 0758486, and Paleo Perspectives on Climate Change (Award No. 1103314). V. Shishov (software development and data analysis) was supported by the Russian Science Foundation (Grant # 14-14-00219). The tree-ring data will be available at the International Tree-Ring Data Bank (ITRDB) web site (https://www.ncdc.noaa.gov/paleo/study/19016).

Mapping fire behaviour under changing climate in a Mediterranean landscape in Greece

AbstractUnderstanding how future climate periods influence fire behaviour is important for organizing fire suppression strategy and management . The meteorological factors are the most critical parameters affecting fire behaviour in natural landscapes; hence, predicting climate change effects on fire behaviour could be an option for optimizing firefighting resource management. In this study, we assessed climate change impacts on fire behaviour parameters (rate of fire growth, rate of spread and fireline intensity) for a typical Mediterranean landscape of Greece. We applied the minimum travel time fire simulation algorithm by using the FlamMap software to characterize potential response of fire behaviour for three summer periods. The results consisted of simulated spatially explicit fire behaviour parameters of the present climate (2000) and three future summer periods of 2050, 2070 and 2100, under the A1B emissions scenario. Statistical significant differences in simulation outputs among the four examined periods were obtained by using the Tukey’s significance test. Statistical significant differences were mainly obtained for 2100 compared to the present climate due to the significant projected increase in the wind speed by the end of the century. The analysis and the conclusions of the study can be important inputs for fire suppression strategy and fire management (deployment of fire suppression resources, firefighter safety and exposure, transportation logistics) quantifying the effect that the expected future climate periods can have on fire suppression difficulty in Mediterranean landscapes.