No abstract

The aim of the study is to analyze the accumulated data on the study of forest territories of the border regions of the Bryansk region that have been exposed to radioactive contamination for their involvement in economic activity, as well as the possible transfer of radioactive materials in forest fires. The area of recorded and unaccounted forests was estimated according to the “Forest Plan of the Bryansk Region for the period 2019-2028” and the results of the analysis of remote sensing data of the earth, the assessment of radiation pollution – according to the radiation surveys of the forest fund and radioecological monitoring of forests, assessment of cesium-137 content – according to radiation monitoring. In the course of the work, the dynamics of the transition of forests from the range of a high level of radioactive contamination to lower ones from 1991 to 2018 slightly changes the total area of contaminated forests by regions was revealed. Top-level values of cesium-137 content in the main types of forest combustible materials, which a dangerous factor is contributing to a significant increase in the content of radiocesium in atmospheric air and the transfer of radionuclides beyond the limits of radioactive contamination zones in a forest fire. The most radiation-hazardous is the forest litter, which contains more than 70% of the total cesium-137 reserve in forest combustible materials, the values of which reach values of 224 kBq / kg in the Krasnogorsk district of the Bryansk region. The obtained forecast of cesium-137 content in the forest litter by the zones of radioactive contamination of forests in the most polluted areas of the Bryansk region for the period up to 2046 indicates the preservation of a high degree of radioactive contamination of forests in the Krasnogorsk and Novozybkovsky districts after more than 60 years after the Chernobyl accident power plants. Due to the high class of natural fire hazard of forests in the south-west of the Bryansk region and the high risk of fires in contaminated areas, it is necessary to assess the degree of danger in the prevention and suppression of radioactive forest fires, especially criterion of the absorbed dose for workers in order to avoid the deterministic effect.

Предложена прогнозная модель лесопожарной обстановки на 10-летний период. В качестве основы прогнозирования используются демографические данные о численности населения, занятого в сельском, лесном и охотничьем хозяйствах, и многолетние данные о лесных пожарах. The paper proposed a predictive model of forest fire situation in the 10-year period in the scale of the Russian Federation. Most of the papers addressing the forecasting of forest fire situation is focused on a certain region of the country: Siberia, the far East, region, administrative district, etc. The present work focused on the preparation of forecast in the scale all of the country. Examples of such generalized figures are the average height above sea level, average annual temperature of the Earth, etc. The purpose of this forecast, unlike the regional ones, is not the design of fire protection measures in the forests of a particular region, and in getting a General idea of trends in forest fire situation at the Federal level for the long term. The initial data for forecasting are data on forest fires from 1965 to 2016. The main methodological approach in this paper is to find factors having a close relationship and have the greatest impact on outcome measures (the number of forest fires, total area burned), followed by construction of a mathematical model. Based on this model can be made a forecast. A large part of forest fires due to human factors. Therefore, the search for factors was performed among demographic characteristics on the public data of the Federal state statistics service. This factor was the number of people employed in agriculture, forestry and hunting farms. The analysis of the relationship of this factor with data on the forest fires and its dynamics in the studied time interval have shown that it can be used as a basis to predict the number and area of forest fires. The forecast is made for a ten-year period up to 2026. If current trends continue, the number of wildfires will remain at the current level or to decline slightly. The average area of forest fires will slowly increase and by the end of the forecast period will come to a stable level. The total area damaged by fire, will gradually decrease. The forecast model assumes the parameters of meteorological factors stable over time and fixed at the level of mean annual values. In reality it is not. In years when weather conditions will deviate significantly from the average, the parameters of the forest fire situation may deviate from the forecast. In this case, our forecast sets a basic reference line determined by demographic factors, as observed in particular years the number of fires will deviate from it in one way or another to the greater, the more abnormal will be the weather conditions in a given year. This applies in particular to forecast the number of fires as the parameter most dependent on specific meteorological conditions.  The forecast of the average area of a fire is less dependent on weather conditions. This value must less to deviate from the predictable.

The article deals with the problem of radioactive forest fires. Authors noted a need to clarify the qualification criteria of forest fires as radioactive and creating their classification. As a criterion for the hazard of radioactive forest fires, the parameters of the minimum significant activity (MSA) and the minimum significant specific activity (MSSA) in forest fuel (combustible) materials (forest litter) for cesium-137 are used, as applied to the fire edge. An approach is proposed for classifying radioactive forest fires on the basis of data on the density of radioactive contamination of forest areas and types of forest conditions. A variant of the scale of categories of radioactively contaminated forest sites and radioactive forest fires (the hazard levels for the prevention and extinguishing radioactive forest fires) is proposed.