| Forest fire is mainly mutational factor and regional change elements of forest ecological system. Forest fire catastrophe refers to the abnormal change of fire and its influence on ecosystem and human social, and forest fires in China have a significantly threat to the national economic development, so the forest fire prevention is important to realize the sustainable development of the national economy. Although the complex mechanism of forest fire, it can be prediction by meteorological factor analysis.The aims of this paper are analysis the relationship between regional forest fire situation and time series.We make a field area experiment that the spatial structure, mortality, plant diseases and insect pests is closely related to the period of forest fire, to research the relationship between variation of the forest fire and time series. Through comparing the occurrence time scale, the strength of forest fire and forest ecosystem state system conditions to screen the mainly impact factor, we study the key ecological factors of fire time series on forest ecosystem change rule and influence in Heilongjiang province, and provide the scientific basis for the forest restoration, forest fire prevention and application.The main results are as follows:1) The fire time series of disaster area changeWe compared the catastrophe period and the damage degree of forest to analysis the time series changes in the area of forest fire, main work is following:through analysis daily variation of disaster area to discussed the disaster control; through analysis of physiological injury trends to explored casualty rate control; through analysis the forest structure variation amplitude threshold to discussed prevention and control of engineering construction; through analysis diseases and pests occurrence degree to explored the ways of prevention; through vegetation regeneration degree analysis to explored the auxiliary mechanism. According to the theory of forest fire disaster time series, daily fire area occurs near the mutation threshold estimation to predict the disaster time for the disaster trend control.2) The fire time series of burns conditionIn the burned area according to the time sequence sample, sample size was100m×100m, and parallel set20samples. The fire intensity catastrophe threshold was compared with forest fire time by investigating injury and fatality rate of shrubs and trees. The result showed that under the same fire intensity, the different time points has the different casualties. So the effective use of forest ecological characteristics can improve the level of forest fire management and the prevention and control ability, and reduce the intensity of low fire casualty rate of trees, and the ecological fire prevention has the practical significance.3) Fire time series of soil physical and chemical properties changesIn the burned area according to the time sequence sample, sample size is100m×100m, and parallel set20samples. Through the investigation of soil physicochemical properties (density, damage type, coverage), we analyzed the impact of forest fire on forest succession trend of time series. The results showed that the low intensity fire limited impact on soil physical and chemical properties, and recovered after3a. Therefore, how to use the forest fire characteristics to achieve the purpose of disaster prevention and reduction and implement the low intensity fires has positive effects on forest protection.4) The relationship between insect disaster and fire time seriesIn the burned area according to the time sequence sample, sample size is100m×100m, and parallel set20samples. We investigated the pest species, distribution and population density by the samples in each wood statistical attack rate and randomly selected5strains as the standard wood. Insect population commonly used unit space (area, volume, plants, etc.) on the average density of insects, such as head/m or head/plant, etc.) and relative density (in the total number of sampling units, appear this kind of insects, the percentage of sampling units, if there is any bug rate, etc.). The forest fire has different influence on plant at different times, and the control efficiency can be improved significantly by learning from the difference of plant physiology at the appropriate time to cut off the food chain of plant diseases and insect pests with fire. Some researches at home and abroad showed that the plans to fire to help prevent the occurrence of plant diseases and insect pests. But, we only study the relationship between fire and insect pest and observe the existing situation to examine the phenomenon. There is not the systemic and continuity and the study is lack of the mechanism of the result in this phenomenon. So, it is necessary to study the mechanism of forest fire in conditions permit conditions.5) Fire the change law of update time seriesIn the burned area according to the time sequence sample, sample size is100m×100m, and parallel set20samples. Through referring to the combustion conditions on the surface of combustible materials, we analyzed that the extent of time series to promote the updating of forest fire.Under the condition of low intensity fire blanks, natural regeneration of larch is evenly distributed, and the number of unit area is higher than unburned. Especially in topsoil naked, without weeds bushes, and moist soil, update frequency is increased. The appropriate use of fire plan promotes natural regeneration, which saves the cost of forestation, induced the formation of mixed forest, increase the the stability of stand, and is beneficial to the recovery of biodiversity conservation and ecosystem. In this paper, using the fire time series as the breakthrough point, we discuss the effects of forest fire on forest fire area, forest structure, and the plant diseases and insect. Due to the complexity of the forest fire environment, the environment changes fast and the influence of uncertain factors, we proposed the idea of building dynamic adaptive variable fire index system framework and discusses the way of the index system and dynamic evaluation for implementing fire disaster analysis method of time series, to meet the needs of different periods fire prevention and forest fire management. |
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