Current state of agroforestry pyrology in Russia

. This article defines the main issues of the research area under consideration, discusses the literature sources of Russian scientists engaged in research in the field of agroforestry pyrology in Russia in recent years. The fundamental issues of fundamental research include the analysis of the occurrence of fires, the characteristics of the spread of fires and their course in various biotopes of agroforestry ecosystems. The nature of the pyrogenic impact is considered from the ecological and evolutionary components of the environment. Applied research issues are developments to improve and increase the efficiency of environmental protection services, assessment and rational use of fires in reclamation plantations. The basic information on fundamental and applied research of domestic scientists is reflected. At present, agroforestry pyrology is a fairly young branch of the science of agroforestry, therefore, insufficient results have been accumulated on theoretical and practical knowledge. The ongoing research is the basis for the development of measures to combat fires in agroforestry landscapes. These activities should include the selection of the most optimal modern means and methods of extinguishing fires, increasing the efficiency of services for the prevention of their development, timely detection, elimination, monitoring, and determining the positive role of fire. The data obtained by domestic researchers constitute a cumulative complex of knowledge about the nature of fires and how to deal with them.


Introduction
The origins of agroforestry pyrology originate from the science of forest pyrology, which has gone quite a long way from its inception to its formation.More than 150 years ago, the first knowledge about forest fires appeared.Melekhov I.S.In a published brochure (1933), he defined forest pyrology as the science of the nature of forest fires and their consequences, a method of fighting fire, and the role of fires in forest ecosystems [1].
One of the modern areas of forest pyrology is agroforestry pyrology, which is aimed at studying fires in forest belts, improving measures to protect forest belts, and the positive impact of fires on agroforestry ecosystems.The development of this area is associated with multiple difficulties due to the economic crisis in Russia, illiteracy and indifference of people regarding compliance with fire safety measures, partial monitoring of fires by the Ministry of Emergency Situations, etc.
Research in agroforestry pyrology is conditionally divided into two categories: fundamental and applied.Fundamental research includes questions on the emergence, spread and development of fires in forest belts, the development of methods for assessing and predicting a fire situation, the analysis of the consequences of damage to tree and shrub vegetation by a pyrogenic factor, monitoring of biogenic emissions of CO 2 , the characteristics of heat transfer and mass transfer of substances formed during fires and creation of stochastic models of combustion processes.These issues affect the function of fire from the point of view of the ecological, evolutionary factor in the formation, growth and development of forest belts.
Applied developments include issues of fire prevention in agroforestry landscapes, methods for detecting and eliminating fires, managing the front of the spread of fire, developing modern methods for aerospace monitoring of fires in such areas, improving methods for optimizing the costs of their elimination, and others.In general, applied tasks are aimed at optimizing the activities of forest protection services, as well as the rational use of available methods for protecting agroforest landscapes in the event of fires.
Basic and applied research are interrelated, with the former serving as the basis for applied testing.However, in practice, there are practically no real boundaries between them.In the works of Artsybashev E.S. [1][2] it is reflected that agroforestry pyrology is characterized by an applied nature, which has an economic component in relation to the field of material production, since the main task is to preserve the integrity of protective forest belts, as well as to increase the level of national wealth of Russia.
Such domestic scientists as Tyurin S. V., Manaenkov A. S., Domanina O. I., Ryabova D. V. and others have made a significant contribution to agroforestry pyrology.RAS, SPbNIILKh, VNIILM, VNIITslesresurs), universities (FGBOU VPO "Ural State Forestry Engineering University", MSUL, FSUE "SSC LPK"), experimental stations (Siberian forest experimental station, Kostroma taiga scientific experimental station, etc.).These organizations carry out research aimed at improving the available technologies in agroforestry, clarifying previously obtained results in relation to the specific conditions of the region and detailing data based on agroforestry studies.

Materials and methods
To write the work, a generalization, systematization of theoretical, methodological publications and monographs of domestic researchers was carried out within the framework of the topic of this article.The search for materials was carried out in Russian databases.The depth of the search was 89 years (from 1933-2022).

Results and Discussion
The origins of agroforestry pyrology begin to develop from the science of forest pyrology, which has passed a rather long way from its inception to its formation.More than 150 years ago, the first knowledge about forest fires appeared.The founder of forest pyrology is Academician of the All-Russian Academy of Agricultural Sciences Melekhov I.S.In a published pamphlet (1933), he defined forest pyrology as the science of the nature of forest fires and their consequences, methods of fighting them, and the role of fires in forest ecosystems [3].
Forest pyrology is an independent scientific field based on theoretical and practical knowledge on the protection of forests from fires.In turn, researchers who have devoted themselves to agroforestry pyrology are studying the burning of forest belts and the consequences of their damage due to the pyrogenic factor [4]. Fires in the agroforestry landscapes of Russia cause great damage not only to agriculture, but also to the environment in general, therefore, they represent one of the most serious problems that have not been fully resolved [5].
It is known from forest pyrology that natural fires are landscape fires, as they arise and spread in various components of natural landscapes.Landscape fires are understood as the spontaneous spread of fire, as a result of which various types of vegetation of forests, fields, steppes and other ecosystems are destroyed.In turn, they are classified into 3 types: forest, steppe and peat fires [6].
It should be noted that the uncontrolled course of the processes of burning grass vegetation in the steppes has similar conditions and factors with agroforestry and landscape fires.In view of the fact that an insufficient number of studies on the problems and specifics of such fires have been carried out so far in agroforestry, it is advisable to mention works on steppe fires as well.
An assessment of the role of steppe fires is given in the work of Dymova T.V. [7].For the steppe zone, grass burns are very dangerous, as in most cases they cause large fires.However, some feed producers see positive aspects in such negative impacts.For example, after burning, the yield of fodder mass increases, which is accompanied by an improvement in the quality of the herbage, the destruction of dead dead wood, and an increase in the intensity of grazing.It should be noted that steppe fires are very similar in nature to grassroots forest fires, but most often spread at a faster rate due to the absence of trees on the way, which play the role of a wind barrier [8].
Shinkarenko S.S. together with colleagues [9] performed an analysis of electronic maps of geographic information systems in order to establish the features of the fire regime in the event of the same fires.Using electronic maps, it is possible to determine not only the level of training, but the effectiveness of fire fighting.The data obtained can later be used in research to study the features of pyrogenic succession in the southern steppe and semidesert zones, where the fire hazard period is quite long.The work [10] studied in more detail the technology of satellite monitoring of grass burns, which are based on automated methods for processing data from remote sensing of the Earth from space based on MODIS satellite images.This technology is based on an automated analysis of the interpretation of burnt areas during the visual interpretation of satellite data.The advantage of this technology is the presence of a long-term archive of thermal points, and the disadvantage is that they are only accounted for relatively large fires.
Fires in agroforestry landscapes can be of natural and anthropogenic origin.Consequently, the sources of their occurrence can be anthropogenic and natural.Anthropogenic sources include unextinguished fires, cigarette butts, much less often broken transparent glass, transparent plastic water bottles left on dry grass, etc. Accordingly, the main anthropogenic factors for the occurrence of fires in agroforest landscapes include: intentional arson, including agricultural burning ; violation of fire safety measures by the population; production activities in the course of logging and agricultural work.The consequences of anthropogenic and natural fires will be the same.According to Kiryukhin S.A. [11], the main reason for the occurrence of steppe burns is the human factor, since people deliberately burn dry grass cover in order to increase the forage areas on which they organize grazing of agricultural animals, as well as to maintain the primary productivity of these lands.
Fires in agroforestry landscapes are much less likely to occur from natural sources, which include lightning discharges, spontaneous combustion of peat, and sparks from friction of tree trunks in dry, hot, and windy weather [12].An analysis of literary sources showed that, in addition to anthropogenic factors, the occurrence and their course in agroforest landscapes are influenced by natural and climatic conditions, among which precipitation, wind speed and direction, temperature and relative air humidity in the surface layer, and the level of moisture content in the surface layer are distinguished.soil, solar radiation and its activity, as well as the cloudiness of the area.In addition, it is known from published sources that, in addition to natural and climatic factors, topographic features of the terrain (terrain relief in areas of fields, as well as forest belts), the development of phenological phases of plants, etc., have an important influence on the occurrence and intensity of fires [11] .
It should be noted that, most often, ignition sources in natural conditions differ from sources in anthropogenic conditions.Fires in agro-forest landscapes most often occur due to fires in the interstrip space, where cereal crops mainly burn, as well as weeds, including medicinal ones in areas of fallows.Fires occur much less frequently in forest belts.Basically, the fronts of fires from the areas of the interstrip space pass into reclamation plantations [13].
The main damaging factors of landscape fires include high combustion temperatures, smoke in areas, and reduced visibility on roads.Poisoning of people and animals with carbon monoxide has also been noted.Landscape fires cause direct and indirect damage.Direct damage combines material losses as a result of the destruction of forests, representatives of flora and fauna, agricultural land, as well as outbuildings and residential buildings.Indirect damage includes material costs spent on the elimination of fires and the restoration of destroyed objects.At the same time, fires lead to the loss of ecological functions in landscapes.As a result of the pyrogenic impact, the growth of wood, the qualitative composition of forests are reduced, soil conditions are deteriorating, and the percentage of windblows and windfalls is increasing.All this contributes to the mass distribution of phytophages, both in forest biogeocenoses and in forest belts [14].
The influence of relief on the occurrence and course of landscape fires is peculiar.For example, fires in the mountains actively spread up the slopes.The steeper the slope, the higher the speed of the fire front.When rising up, the fire is located at an insignificant distance from the grass along the lower part of the tree crowns, which causes them to heat up, dry out and accelerate ignition.Warm air, rising up the slope, causes "draft" and thereby increases the speed of the fire front [15].Similarly to forest fires, in agroforestry landscapes, an increase in the speed of the fire front occurs if the source of ignition occurs in the lower part of gullies and ravines.Flat terrain with a small slope (3-8%) also has little effect on the change in wind speed.Hilly terrain with steep slopes of more than 20% has a significant impact on the increase or decrease in the speed of the front of landscape fires, depending on the direction of the wind [16].
At the moment, there is no term in forest pyrology for fires in agroforestry landscapes.According to their specificity, such fires can be considered as combined, that is, they conditionally include 2 types: forest, mainly in pegs, copses and steppe.However, it must be taken into account that the structure of forest belts, as well as the grass stand in them, the species composition of such reclamation plantations differ significantly from the same indicators in the forest.Similar to the areas occupied by trees and shrubs with herbage, in terms of growth conditions, structure, and species diversity of herbaceous vegetation, there will be significant differences in the interstrip space and the steppe.Consequently, the course of fires in such ecosystems will also differ significantly.Based on this, it is advisable to propose a new term in agroforestry as the fourth type of natural fires -"agroforestry landscape fires", which can spread in areas with agricultural land, as well as in the steppe bordering forest belts of various structures, passing into these meliorative plantations and accumulating in them.Since each type of protective forest belts has differences in the range of species of trees and shrubs, longitudinal profile, and completeness of the forest stand, then, accordingly, the course of fires in each of these reclamation plantations will have its own characteristics.Depending on the area of fires, they can be focal (fires up to 0.1 ha) and develop to landscape ones.Thus, the frequency of occurrence and the rate of spread of fires in reclamation plantations, in addition to weather conditions, also depends on the population density of the administrative-territorial units adjacent to the agroforest landscapes.In her works Gabysheva L.P. and Isaev A.P. [17] determined the dependence of the number and density of the population on the occurrence and spread of fires.The pair correlation coefficient is in the range (r = 0.95…0.99).Also, these scientists established a negative correlation between the calculated values of the amount of precipitation during the fire hazard period and the frequency of fires (r = -0.53).
Fires in plantations are pollutants of agricultural land, since smoke during a fire enhances the greenhouse effect of the atmosphere, thereby worsening the microclimate in agroforestry landscapes.Also, as a result of the combustion processes of various types of vegetation in a gaseous environment, carbon monoxide is formed.All these factors adversely affect not only flora and fauna, but also human health.Smoke impairs visibility on roads, hinders agricultural aviation flights [18].
In his research, Dobrovolsky G.V. [19] proposes the introduction of a specialized scale for assessing the degree of risk of fires depending on the damaged areas, applicable to forest belts.So, according to his data, the greatest danger is represented by forest belts in which coniferous species grow, since they are most littered with logging residues, and the needles contain a large amount of essential oils and resinous substances, which contributes to a significant increase in the rate of spread of fire.Therefore, for fire prevention of forest belts, trees consisting of the most fire-resistant hardwoods, such as drooping birch, balsamic or black poplar, and gray alder, should be planted.According to the available data [4], [9], the optimal width of predominantly coniferous plantations to prevent crown fires should be 15 m.m, on which all grass cover is removed.
After fires in this area, processes of restoration of woody, shrubby and herbaceous vegetation take place.These processes represent a model of changes in the original plant mass after pyrogenic exposure and are called pyrogenic succession.The seeds of a large number of herbaceous plant species, including ephemera and ephemeroids, can survive a landscape fire.The process of restoration of grass vegetation, in turn, depends on the intensity of landscape fires, the species composition of the herbage in neighboring areas not covered by ground fire, the presence of seeds in the soil that are most resistant to heat or the deep location of the root system of herbaceous plants, the chemical composition of the soil, etc. .[20].
In the works of Razumovsky [21], it is noted that disturbances in the natural balance of the components of the natural environment lead to the emergence of dynamic communities on the territory of one association, while the preservation of the dominant species of this territory is observed.In case of violation of the vital activity of the communities themselves, successional changes or successions occur.If the change in forest belts took place under the influence of external factors in relation to the community, then we are talking about an exogenous change.One of the followers of the views of F. Clements is Razumovsky S.M., who developed a classification of successions for a large number of geobotanical regions of the globe.It is known that in other scientific disciplines there is the concept of succession.So, for example, in soil science, such a concept as soil succession is used, which is the main type of morphogenetic dynamics of the soil cover, which is a local time series of soils, which are characterized by certain stages of development [22].
After fires in forest belts in heavily damaged areas, a change in design is often noted, and in some places even rows, wind permeability increases significantly.Also, such damage leads to a change in the sanitary condition and taxation indicators: the completeness of the forest stand, species number, wood stock, the presence of undergrowth and undergrowth, etc.Over time, there is a change in the composition of the forest stand, age structure, which is a consequence of a change in the type of tree species and the nature of clearings [ 23].As a result of the pyrogenic impact, changes in the composition of tree species are observed in plantations, since some species are completely destroyed, such as fruticose lichens and green mosses [24].Accordingly, the impact of fire on plant communities in forest belts is due to the fact that a structure of different ages of tree species is formed, and the species diversity of herbaceous vegetation in such plantations is temporarily reduced [8].
Sannikov S.N. [25], together with colleagues, studied the intensity of crown fires in closed pine forest belts.They established the need to create forest strips with a width of at least 150 m from mixed tree species.In these reclamation plantations, deciduous trees play the role of a fire barrier.Currently, this development is one of the most effective and costeffective ways to protect against crown and ground fires in agroforestry landscapes in our country.At the same time, in the conditions of Western Siberia, coniferous crops should prevail in the forest belts, with the exception of lichen pine forests, due to which the natural renewal of deciduous species occurs, and in case of their deficiency, it is necessary to replant deciduous forest belts.According to Sokolova G.G. [26] found that agricultural burns as a result of ground fires negatively affect the species composition and structure of the herbage in plantations, which is expressed in a decrease in species and phytocenotic diversity, a change in the ecological structure of the biogeocenosis, a deterioration in the processes of regeneration of the forest stand, and, as a result, a decrease in the sustainability of forest forests.ecosystems.Glagolev V.A. [27] carried out a comparative analysis of the combustibility of steppe and forest materials, which differ in the degree of readiness for combustion, which in turn depends on the phenological phase of the plant, planting density, and climatic conditions.According to his data, the combustibility of plants is determined not only by the properties of the herbaceous cover, but also by the speed of propagation, the ability to overcome various obstacles in its path (roads, watercourses, firebreaks, etc.).He proposed a practical method for calculating the occurrence and spread of grassy fires, which can be used to develop fire prevention recommendations and measures on the territory of the constituent entities of the Russian Federation.Titova E.V. [28] found that fire resistance and natural regeneration of tree species depend on the type of tree vegetation in forest belts.Depending on the type of trees, fires are characterized by different propagation speeds, as well as burning intensity.Dampgrowing (containing moisture in the trunks) trees have high fire resistance, since they ignite less and burn much more slowly, releasing fewer calories.Fire-resistant trees include deciduous crops: oak, elm, birch, aspen and others.According to Titov E.V., the natural regeneration of burnt forests should be understood as the restoration of vegetation due to subsequent reproductions.This indicator depends on the area of seeding, as well as the development of living grassy cover and the degree of mineralization of the soil surface.The sources of natural renewal include the surviving seeds of economically valuable tree species (birch, aspen, pine), which are sown in open spaces.Natural regeneration is promoted by early frequent and abundant seeding, the presence of light flying seeds, unpretentiousness to soil conditions, as well as fairly rapid growth and resistance to low temperatures.
In the works of Ilyina [29], it was noted that under the action of fire, the phytodiversity of forest belts decreases, the aboveground and underground parts of plants are destroyed, leading to the death of not only young, but also mature representatives of tree and shrub vegetation.As a result of the destruction of generative shoots, the seed productivity of forest crops decreases, the number of seeds in the soil decreases and, accordingly, the number of future seedlings.
The spreading fire as a result of a fire destroys the sources of pathogenic and opportunistic infection, phytophages [30].Under the influence of fire, weakened plant organisms die first, thereby accelerating the thinning of forest belts, which leads to the intensive growth of preserved tree and shrub vegetation.Accordingly, fires not only affect the components of forest belts, but also make significant changes to ecosystems as a whole [31].
As early as 1980, in the works of Kaplyuka and Polyakov [32], the negative effect of fires in forest belts on the natural regeneration of tree vegetation was established.So, in burnt areas and conflagrations of forest belts after ground fires, only in the first 3-6 years, natural renewal of pine is observed.Then, due to the strong growth of cereal herbaceous vegetation and the sodding of the soil, the growth of young shoots stops.After 25-30 years after the fire, the meadow-herbaceous cover changes to mortmass (forest litter), consisting of vegetative and generative organs of plants, waste products of fauna, dead entomofauna, fruiting bodies of fungi, etc. Due to the formation of forest litter in reclamation plantations create optimal conditions for the renewal and growth of tree crops [33].
One of the sensitive components to changes in the environment is the soil, while the negative impact is reflected not only in the state of the soil cover, but also in the intensity of the soil-forming process.The occurrence and spread of fires in agroforestry landscapes have both direct and indirect effects on soil organisms.In this case, direct impact is understood as a short-term change in the soil cover that occurs during direct thermal action on the components of the biogeocenosis.Indirect influence should be understood as implicit changes in the morphological structure of the soil profile immediately after the fire, including changes in plant communities, changes in climatic conditions within the ecosystem, changes in the form of organic matter, etc. [24].
As a result of fires in agroforest landscapes, changes in the abundance and composition of fauna are noted, as a result of which the number of animals, birds and insects decreases.Mostly representatives of invertebrates living in the herbage suffer from fire, for example, representatives of the order of beetles (Coleoptera), the order of homoptera (Homoptera) and the order of Lepidoptera (Lepidoptera).The recovery of representatives of invertebrates living in the forest litter, such as centipedes (Myriapoda), certain species of spiders (Araneae), bedbugs (Heteroptera), is rather slow.Available data in the literature indicate that, on average, insects are recorded in burnt forest belts only after 3 years.Fire has the least effect on insects living in deeper soil layers (more than 15 cm), for example, ground beetles (p.Ceroglossus) and dark beetles (Tenebrionidae) [34].
The strength and nature of the impact of fires on the organic matter of the soil also directly depends on the type of vegetation.In some cases, during strong fires in the forest belts, an increase in the carbon content is observed in the soils; this is due to the influx of a large amount of charred tree remains into the soil [23].
Research Ryabova D.V. [35] refined the canopy herbaceous vegetation of forest belts for ground fires in agroforest landscapes of the steppe climatic zone.In the case of weak overgrowing with herbaceous vegetation, the grassy cover, consisting of litter and individual dried trees, burns out mainly.At the same time, localization occurs in the forest belt, and the rate of fire spread decreases, respectively, the damage to trees is weak (spread rate up to 2 m/min, the burnout area reaches up to 5.9 m 3 /ha).The average degree of overgrowth of herbaceous vegetation in plantations of black locust is ignited grass cover, weakened and dead trees (the speed of the fire front is up to 3 m/min, the burnout area reaches up to 22.4 m 3 /ha).With a high degree of overgrowth of forest belts with herbaceous vegetation, not only this vegetation, but also the forest stand ignites (the fire spread rate is up to 8 m/min, the burnout area reaches up to 58.2 m 3 /ha).

Conclusion
Summing up, it should be noted that in modern conditions, the available data on agroforestry pyrology clearly demonstrate progress in controversial issues related to the occurrence, spread and course of fires in the agroforestry landscapes of Russia.The works of domestic scientists contain the results of fundamental and applied research on the nature of fires, as well as the processes of restoring environmental elements after their impact.Unfortunately, most studies reflect the assessment of the impact of the pyrogenic factor on taiga ecosystems, and there are few works on the steppe and forest-steppe regions.Therefore, to develop a holistic view of fires as a complex ecological and evolutionary factor in the formation and existence of forests in the steppe zone, complex, interdisciplinary studies are needed.Based on this, domestic researchers are faced with the task of further agroforestry research aimed at developing strategic and technical issues for protecting forest belts from the effects of the pyrogenic factor.