587 research outputs found

    Implementing fire history and fire ecology in fire risk assessment: the study case of Canton Ticino (southern Switzerland)

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    The understanding of the ecological role of wildfires and the knowledge of its past natural and cultural dynamics in different ecosystems have been recognize as a prerequisite for a sustainable land and ecosystem management. The main objective of this work is to propose a methodological approach for implementing the knowledge derived from studies of fire history, fire ecology, and fire suppression strategies in fire risk analyses in a low-to medium fire-prone region such as the Canton Ticino

    Looking for differences in wood properties as a function of the felling date: lunar phase-correlated variations in the drying behavior of Norway Spruce (Picea abies Karst.) and Sweet Chestnut (Castanea sativa Mill.)

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    A large-scale field experiment on the drying behavior of Norway Spruce (Picea abies Karst.) and Sweet Chestnut (Castanea sativa Mill.) in relation to the felling date was conducted over a period of 24weeks in order to investigate the existence of variations linked to lunar rhythms, which are mentioned as having a role in many traditional forestry practices. The measured criteria were the water loss from fresh to dry state, the shrinkage linked to this water loss, and the relative density (ratio between the dry density and the initial fresh density) for both sapwood and heartwood in Picea and heartwood in Castanea. In addition to seasonal trends, slight but significant variations with lunar periodicities (both synodic and sidereal; to a much lesser extent tropic) characterize the three investigated criteria. These lunar rhythmicities occur in both Picea and Castanea, in heartwood and sapwood. These results raise new questions and perspectives about a rhythmic character of the wood–water relation

    Field evaluation of entomopathogenic nematodes against orchard pests

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    Survival of pest in micro-plot trials (container studies) or field plot trials was monitored after exposure to commercially used EPN strains. Experimental plots were artificially infested with pest larvae that naturally burrowed into the soil for diapause. Either larval mortality or adult emergence, was assessed to estimate the control effect of the EPN treatment. Here we present preliminary results from three ongoing projects

    Looking for differences in wood properties as a function of the felling date: lunar phase-correlated variations in the drying behavior of Norway Spruce ( Picea abies Karst.) and Sweet Chestnut ( Castanea sativa Mill.)

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    A large-scale field experiment on the drying behavior of Norway Spruce (Picea abies Karst.) and Sweet Chestnut (Castanea sativa Mill.) in relation to the felling date was conducted over a period of 24weeks in order to investigate the existence of variations linked to lunar rhythms, which are mentioned as having a role in many traditional forestry practices. The measured criteria were the water loss from fresh to dry state, the shrinkage linked to this water loss, and the relative density (ratio between the dry density and the initial fresh density) for both sapwood and heartwood in Picea and heartwood in Castanea. In addition to seasonal trends, slight but significant variations with lunar periodicities (both synodic and sidereal; to a much lesser extent tropic) characterize the three investigated criteria. These lunar rhythmicities occur in both Picea and Castanea, in heartwood and sapwood. These results raise new questions and perspectives about a rhythmic character of the wood-water relatio

    La successione giurassica di Passo Brocon (TN): caratterizzazione, interpretazione paleoambientale e confronto con il Giurassico dellâ Appennino centrale

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    In this thesis I make a characterization and paleoenvironmental interpretation of the Jurassic succession cropping out at Passo Brocon (north-eastern Italy). From the geological mapping of the area, the Rosso Ammonitico Veronese Formation resulted absent. A comparison with the geometries and facies of the Jurassic units of the Umbria-Marche region (Central Apennin) has been made in order to propose a hypothesis explaining this formational gap

    Linking Forest Fire Regimes and Climate—A Historical Analysis in a Dry Inner Alpine Valley

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    Forest fire regimes are likely to experience considerable changes in the European Alps due to climatic changes. However, little is known about the recent regional fire history and the impact of local climate on the fire regime during the 20th century. We therefore reconstructed the fire history in a dry continental valley of the Swiss Alps (Valais) over the past 100years based on documentary evidence, and investigated the relationship between the reconstructed fire regime and the local climatic variability. We compared the impact of temperature, precipitation, drought and dry foehn winds on fire frequency, extent of burnt area, and fire seasonality on various spatial and temporal scales. In the subalpine zone, the fire regime appears to have been mainly driven by temperature and precipitation, whereas these variables seem to have played only a secondary role in the colline-montane zones. Here, foehn winds and, probably, non-climatic factors seem to have been more important. Temperature and precipitation played a major role in shaping fire frequency and burnt area in the first half of the 20th century, but lost their importance during the second half. Our case study illustrates the occurrence of different fire regime patterns and their driving forces on small spatial scales (a few hundred square kilometers). We conclude that the strong rise in temperature over the past century has not profoundly changed the fire regime in Valais, but in the second half of the 20th century temperature was no longer a strong determinant for forest fires as compared to human activities or biomass availability in forest

    The Roman Legacy on European Chestnut and Walnut Arboriculture

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    The political and administrative unification process under the Roman Empire resulted not only in a progressive linguistic, religious, and cultural homogenisation of the concerned population, but also in the need of trade and exchanges for satisfying new dietary habits and markets. In this paper, we use palaeoecological pollen and macroremain records extracted from Neotoma online database and from scientific literature to analyse the contribution of the Romans in the distribution and cultivation history of Castanea sativa and Juglans regia, two tree species, which are usually considered highly connected with Romanisation. Our results highlight a substantial difference in the impact of the Romans on the history of the two species between the territories of the Western and Eastern Empire, where the Roman influence is much less evident. In the western territories, Juglans regia experienced a significant pre-Roman increase and spread, which was only partially intensified under Roman domination. Castanea sativa, on the contrary, benefited from a significant boost following the Roman conquest, especially in the mountain areas south of the Alps and in France. After the fall of the Roman Empire this led to the traditional medieval chestnut civilisation in which the chestnut tree became a main source of livelihood

    The biological basis of anxiety disorders

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    openTrattazione dei principali disturbi d'ansia secondo una prospettiva psicobiologica. Tale elaborato ha come obiettivo quello di fornire una panoramica relativamente ai fattori neurobiologici alla base dei disturbi d'ansia, in particolare rispetto al disturbo di panico e al disturbo d'ansia generalizzato. Vengono inoltre approfonditi i principali trattamenti farmacologici e psicologici impiegati nella cura di tali disturbi

    Cluster recognition in spatial-temporal sequences: the case of forest fires

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    Forest fire sequences can be modelled as a stochastic point process where events are characterized by their spatial locations and occurrence in time. Cluster analysis permits the detection of the space/time pattern distribution of forest fires. These analyses are useful to assist fire-managers in identifying risk areas, implementing preventive measures and conducting strategies for an efficient distribution of the firefighting resources. This paper aims to identify hot spots in forest fire sequences by means of the space-time scan statistics permutation model (STSSP) and a geographical information system (GIS) for data and results visualization. The scan statistical methodology uses a scanning window, which moves across space and time, detecting local excesses of events in specific areas over a certain period of time. Finally, the statistical significance of each cluster is evaluated through Monte Carlo hypothesis testing. The case study is the forest fires registered by the Forest Service in Canton Ticino (Switzerland) from 1969 to 2008. This dataset consists of geo-referenced single events including the location of the ignition points and additional information. The data were aggregated into three sub-periods (considering important preventive legal dispositions) and two main ignition-causes (lightning and anthropogenic causes). Results revealed that forest fire events in Ticino are mainly clustered in the southern region where most of the population is settled. Our analysis uncovered local hot spots arising from extemporaneous arson activities. Results regarding the naturally-caused fires (lightning fires) disclosed two clusters detected in the northern mountainous are
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