AbstractThe weather conditions determine the dynamic forest fire risk. In Poland, the dynamic forest fire risk is calculated using a method elaborated at the Forest Research Institute. The forest fire risk degree (4-level scale) is calculated every day at 9:00 am and at 1:00 pm during the fire season (1.03 till 30.09) for 60 prognostic zones selected on the basis of stand and climatic conditions. 97% of all annual forest fires occur during the fire season. Surface fires are a significant part of the fires (90%) and occur in forest stands where pine is the dominant species. The purpose of the research was to prepare a new method of forecasting forest fire risk, which would enable a more precise method of evaluation of the risk of an outbreak of fire in relation to the existing and forecast meteorological conditions in forests. The results obtained during testing of this method indicate a high accuracy in forecasting fire risk and a satisfactory precision of formulae for calculating moisture content of pine litter.The assumptions of the new method included: –possibility of determining the actual risk of fire for the given area, being the average for all measurement points located on the terrain equally those in which the moisture content measurement of litter has not been performed,–possibility of forecasting the risk of forest fire for the afternoon in the morning hours of the given day,–possibility of forecasting fire risk for the following day,–forecasting moisture content of litter for the afternoon and of the given day and for the following day,–drawing up a method enabling limitation of operational costs of fire prevention system.

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A navegação consulta e descarregamento dos títulos inseridos nas Bibliotecas Digitais UC Digitalis, UC Pombalina e UC Impactum, pressupõem a aceitação plena e sem reservas dos Termos e Condições de Uso destas Bibliotecas Digitais, disponíveis em https://digitalis.uc.pt/pt-pt/termos.Conforme exposto nos referidos Termos e Condições de Uso, o descarregamento de títulos de acesso restrito requer uma licença válida de autorização devendo o utilizador aceder ao(s) documento(s) a partir de um endereço de IP da instituição detentora da supramencionada licença.Ao utilizador é apenas permitido o descarregamento para uso pessoal, pelo que o emprego do(s) título(s) descarregado(s) para outro fim, designadamente comercial, carece de autorização do respetivo autor ou editor da obra.Na medida em que todas as obras da UC Digitalis se encontram protegidas pelo Código do Direito de Autor e Direitos Conexos e demais legislação aplicável, toda a cópia, parcial ou total, deste documento, nos casos em que é legalmente admitida, deverá conter ou fazer-se acompanhar por este aviso. Forest fire risk related to the railway transport and evaluation of the effectiveness of firebreaks Autor(es):Szczygie, Ryszard; Kwiatkowski, Mirosaw; Koakowski, Bartomiej; Piwnicki, Józef AbstractThe study contains an evaluation of the occurrence of forest fires caused by rail transport and the effectiveness of the firebreaks beside railway lines. Analysis was conducted on the basis of information given in a questionnaire completed by forest administration units, inspection of the actual condition of equipment and maintenance of firebreaks and data are obtained from Polish State Railways and the State Fire Service. Analysis showed that approximately 65% of firebreaks are located in forests most subject to forest fires, 90% of firebreaks are made in pine stands, mainly of over 30 years of age (81.8%). Most forest fires occur in coniferous forest habitats (58.3%). Over 60% of all fires occurred in pine stands. Most frequently stands aged from 30 to 60 years (28%). From analysis of the effectiveness of the application of firebreaks beside railway lines it is shown that the first furrow of the firebreak was crossed by 27.3% of all fires. The conduct of extinguishing operations in the case of forest fires adjacent to railway lines is significantly hindered primarily by the late discovery of the fire, difficult access and initiation of burning along a significant length. The conducted investigations indicated the necessity of making and maintaining firebreaks in order to reduce the risk of fire to adjacent forest areas, which appropriately maintained are capable of reducing the risk of fire. The accuracy of this statement is also confirmed by the fact that such a method of protection is applied in many European countries. On the basis of the analysis conducted, a modification proposal has been drawn up for the existing firebreaks also with guidelines, concerning forest fire prevention in forest areas.

Abstract. The paper presents a new method of classifying forest areas with regard to fire hazard. In comparison with the rules in force in Poland, in determining fire hazard not Selianinov's hydrothermal coefficient neither air pollution coefficient have been applied. As concerns stand criterion, 3 to 6 forest habitat types have been added to the list of the most flammable forest habitat types, while stand age has not been taken into consideration. The number of fires criterion has been replaced by a more objective one -fire density, that is the number of fires per 1000 hectares of forest area. Moreover, the anthropogenic criterion has been added, taking into account the number of inhabitants per 1000 hectares of forest areas, which is related to forest fire occurrences. This method enables classification on different administration levels applying uniform criteria.On its basis, classification of fire hazard have been performed for forest districts, counties, sub-regions, provinces and regional directorates of the State Forests in Poland.