© iForest -Biogeosciences and Forestry IntroductionThe general response of most countries to the problem of an increasing number of fires and burned areas has generally been to strengthen fire suppression capacity (Costa Alcubierre et al. 2011). France, Greece, Italy, Spain and Portugal spend a total of 2500 million Euros annually in the fight against forest fires, 60% of which allocated to cover costs related to suppressing fires, while only 40% is invested in activities targeted to prevention (EFIMED 2012).Despite the high investment to improve fire suppression resources, mainly through expenditure on important aerial fleets, such as in Spain, Greece or Italy, the phenomenon continues to be characterized by an aggressive trend, with a progressively reduced interval between dramatic years.Wildfires occurring during prolonged and severe heat waves (such as in 2003 for Portugal, 2006 for Spain, 2007 for Algeria, Italy, Spain and Portugal, 2010 for Russia, 2012 for all the Mediterranean countries including Algeria) demonstrate that a different approach must be considered for tackling the problem of forest fires. This means a shift from the short term policy, which is mainly based on huge investments for suppression measures, to a long term preventive policy (Birot 2009, Montiel & Herrero 2010.The key purpose of fire prevention measures is to reduce the number of fires through hazard reduction, education, and law enforcement. Improving prevention strategies seems mandatory if a further reduction in the mean yearly burnt area is to be pursued (Ruiz-Mirazo 2011). Fuel treatment and wildfire minimizationAn appropriate approach to wildfire prevention must be aimed at both lessening the possibility of a fire occurring and minimizing its spread should one occur. This can be achieved through fuel treatments for biomass reduction, which are paramount to wildfire abatement (Omi & Martinson 2002). To reduce fire damages, an infrastructure of roads and water supply should be constructed, firebreaks and fire detection systems established, an immediate and efficient intervention of ground crews ensured, but above all, fuel treatments should be timely executed (Leone et al. 2000).Fuel treatments are a key factor to decreasing wildfire risk (Omi & Joyce 2003): they target different fuel components in order to achieve both forest structures and fuel characteristics which are able to reduce the likelihood of fire spread.Fuel treatments are mainly aimed at eliminating the vertical and horizontal continuity of fuels, in order to disrupt the vertical progression of fire (passage from surface fuels to ladder fuels to canopy fuels), and its horizontal progression, especially from crown to crown (Scott & Reinhardt 2001, Graham et al. 2004.Activities aimed at reducing surface fuels (low vegetation, woody fuel, shrub layer) decrease the chances of surface fires igniting ladder fuels and canopy fuels (Pollet & Omi 2002, Fernandes & Botelho 2003.The range of possible treatments to modify forest fuels is rather wide, varying from pruning (Le...
[1] The main problem encountered when applying remote sensing and geographic information systems techniques for wildfire risk assessment is the necessity to integrate different data sources. The methods applied so far are usually based on regression techniques or on coefficients relying on experts' knowledge. Hence fire managers are seeking an unbiased statistical model able to highlight the multivariate spatial relationships between the predictor variables, yielding understandable output readily accessible to end users. The present research aims to test the capability of classification and regression trees (CART) analysis to assess long-term fire risk at a local scale. The CART analysis is a nonparametric statistical technique which generates decision rules in the form of a binary tree, for a classification or a regression process. A fire-prone study area was selected in the southeast of Italy. Fire ignition points, relative to a 7 year period (1997)(1998)(1999)(2000)(2001)(2002)(2003), were used to derive a fire occurrence map through a kernel density approach. The resulting map was then used as input response variable for the CART analysis with fire danger variables used as predictors. The rules induced by the regression process allowed the definition of different risk levels, expressed as 30 management units, which is useful for producing a fire risk map. The result of the regression process (r = 0.77), the capability of the CART analysis to highlight the hierarchical relationships among the predictor variables, and the improved interpretability of the regression rules represent a possible tool useful for better approaching the problem of assessing and representing fire risk.Citation: Amatulli, G., M. J. Rodrigues, M. Trombetti, and R. Lovreglio (2006), Assessing long-term fire risk at local scale by means of decision tree technique,
In European mountain regions, forests play an important role in the mitigation of risk due to natural hazards such as landslides, rockfalls, floods and avalanches.\ud \ud Conifer species usually provide a protective effect at higher altitude, while at lower altitudes broadleaf species are dominant. These forests are or were often managed as coppice systems.\ud \ud The high stem density of coppice stands, their rapid growth and the permanence of root systems in the soil can be considered as assets in terms of protective function. However, these considerations are poorly researched and there is generally a lack of studies investigating the suitability of coppice as protection forests. The issue is relevant, considering that many coppice stands in mountain regions have become uneconomic and are now abandoned and overaged. Whether and how to manage these forests stands is a key question for practitioners.\ud \ud In this contribution we analyze the implications of coppice management for slope stability and in particular to mitigate shallow landslides, focusing on root reinforcement, the main mechanism by which vegetation can reinforce slopes.\ud \ud We review available studies concerning root distribution and dynamics in coppice stands to formulate hypotheses about their contribution in terms of root reinforcement. Finally we highlight the lacks of knowledge and the further steps needed to properly evaluate the effectiveness of the coppices in protecting against shallow landslides
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 nonserotinous 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.
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