The Response of Wood Species to Industrial Atmospheric Emissions

Changes in the ecological situation of the planet as a whole and many industrialized countries in the second half of the 20th century led to a revision of ecological concepts of nature protection, the search for new effective methods for assessing environmental pollution and the condition of biota at all levels of its organization, the development of new ecological standards for permissible anthropogenic loads on natural systems. Vegetation is the most important component of biogeocenosis, providing the vital activity of other biotic components. Changes in vegetation under the influence of various environmental factors influence to the biogeocenosis condition as a whole and, as a result, can be used as diagnostic signs. Phytoindication can be carried out by the response of plants in the species most sensitive to pollutants, or by the accumulation of harmful substances in the body of plants. Therefore, among plants, bioindicators with a high sensitivity to pollutants and storage bioindicators are distinguished. The classification of the principles and levels of phytoindication can be classified according to the generality of research methods phenological methods, morphoand biometric, anatomical-cytological, physiological; biochemical, biophysical, floristic , genetical, biocenotic, ecosystem.
In this regard, phytoindication is singled out in the monitoring system - as one of the methods for assessing the quality of the environment.
Phytoindication methods are highly sensitive. They allow to:
i. To register air pollution 3-5 times lower than the sanitary and hygienic MPC (Maximum Permissible Concentration);
ii. Practically without physical and chemical analyzes of air samples or with their limited number to determine the levels of air pollution in large areas;
iii. To determine the level and danger of the impact of pollutants on ecosystems;
iv. To study the nature of anthropogenic digression of ecosystem components;
v. To identify the relative role of individual large sources of emissions and the environmental hazard of individual ingredients in the total pollution of the environment and their impact on ecosystems;
vi. To determine the permissible or critical loads of pollutants for biota, to develop environmental standards for anthropogenic impacts on ecosystems;
vii. To provide a scientific basis for forecasting the development of the ecological situation in the region and for the development of activities to improve the environmental condition.
The dendrochronological method allows it possible to study changes in climatic conditions on the planet and the effect of various ecological and anthropogenic factors on woody plants of an ecosystem. A reliable correlation has been established between the levels of air pollution by pollutants and a decrease in radial annual growth in tree species [1]. Some methodological rules have been developed to improve the reliability of the dendrochronological method for the bioindication of air pollution. It is also perspective because it allows to calculate the decrease in the growth of wood per year and, therefore, the economic damage from air pollution, and at the same time to assess the state of forest ecosystems [2]. In this regard, the purpose of our research was: a comprehensive assessment of the impact of industrial emissions from gas processing enterprises of the Kashkadarya region on the dendrological indicators of some tree species as the main link in the industrial ecosystem. Scientific substantiation and selection of criteria for the stability of tree species; scientific substantiation of phytoindication methods-identification of the most sensitive indicator tree species and selection of express methods for assessing industrial pollution.
We aimed to study the dynamics of changes in the nature of metabolic, photochemical disturbances in order to better understand the mechanism of photosynthesis disturbance. For this, we have chosen five landscaped trees (Ulmus pumila L. - Siberian elm, Acer negundo L. - Аsh-leaved maple, Fraxinus syriaca Boiss. - Syrian ash, Populus alba L. - White poplar, Morus alba L. - White mulberry tree species of different stability that grow on the territory of the Mubarek gas processing plant (1st experience), Shurtanneftgaz UDP (2nd experience), Shurtan gas chemical complex (3rd experience) under the influence of S02 and a relatively clean sanitary zone of the city of Karshi (Control). Besides, we investigated the agroclimatic production characteristics of the study areas (Table 1). As can be seen from (Table 1), the pollution level of industrial zones is relatively high concerning the sanitary zone. To assess the pollution level of the industrial zone, we used some anatomical features of annual shoots of tree species (diameter of annual shoots, bark thickness, annual growth of wood) (Table 2).

Table 1: Brief description of the study areas (average annual data for 2016-2017).

Table 2: Indicators of anatomical features of annual shoots of the studied tree species.

As can be seen from (Table 2), we traced the change in the anatomical features of the growth of annual wood in some tree species and obtained the following results. The highest growth of annual wood was observed in trees growing in the sanitary zone of the city of Karshi. It is noteworthy that in this area we have identified the minimum content of pollutants in the air (Table 1). Slightly lower growth of annual timber was observed in shurtan GCC. A similar relationship was typical for MGPP and Shurtanneftgaz but note that the difference between these three areas is statistically insignificant (Table 2). The smallest increase in wood and bark thickness was observed at MGPP and was 2.0±0.11 and 1.2±0.03 mm for maple, respectively, and the content of atmospheric emissions at these industrial facilities was the highest. It is noted that the difference between these two points is statistically insignificant. The difference in the length of the annual growth of wood of the studied species between all the other regions of the study is statistically significant. As can be seen from (Table 2), for mulberry, elm and ash, the difference in the growth of wood is insignificant, which indicates their resistance to industrial emissions.
Thus, considering the change in the diameter of the shoot, the annual growth of wood, in the studied species, we see a relatively clear inverse dependence of this parameter on the concentration of harmful substances in the air. According to literature data [3], it is known that SO2 has an inhibitory effect on growth processes, given that one of the main emissions of the studied enterprises is SO2, therefore, we observe a weakening of the apical and lateral growth of shoots of the studied breeds. These changes are manifested not only in a weakening of the annual growth of wood, but also in a decrease in the formation of latewood [4,5].

There are 21 possible types of growing conditions, or types of ecological and plant complexes (ERCs), as a combination of types of ecological conditions and types of vegetation in the world. The distribution of ecological and plant complexes of the world is shown in Figure 1. On the basis of vegetation ordination, an ecological and plant map of the Earth is compiled (Figure 1). The types of ecological and plant complexes shown in the ordination scheme are shown on this map. The contours of the complexes themselves are elongated mainly in the latitudinal direction, which indicates the predominant role of heat supply in the distribution of vegetation, reflecting mainly zonal botanical and geographical relations. As a result of the analysis of the ecological and plant map of the world, the main botanical and geographical relations of the planetary level, the ecological conjugacy of environmental factors and vegetation were identified, which largely determine the structural and functional organization of forest vegetation at other structural levels of vegetation: regional, landscape. Maps of ecological and plant complexes make it possible to directly assess the ecological stability of plant taxa, their changes in various combinations of heat and moisture availability. Such maps, in essence, are a cartographic model of possible changes in the structure under various variants of environmental changes. Vegetation with a high level, an indicator of ecological compliance occupies ecological optima and is the most environmentally sustainable. At the global level of the structural organization of vegetation, changes in the structure and, consequently, in its productivity in ecotone areas are most likely.
Here the vegetation is most sensitive to the changes taking place. In this regard, such areas are the most vulnerable, they are characterized by increased indication properties. Therefore, the organization of biosphere stations for monitoring the natural environment, primarily vegetation cover in such places is most preferable. The map of ecological and plant complexes of the Earth) clearly reveals the patterns of spatial distribution of vegetation. Each level of heat supply, characterized by a sum interval of 400°, corresponds to a specific subzone of vegetation. Another pattern, called Buks II [10] provincial, reflects the dependence of the typological composition on the radiation index of dryness under equal conditions of heat supply. The quantitative relationships between the combination of gradation of the leading environmental factors and syntaxons can be used in predicting the structure of the vegetation cover structure in the course of environmental monitoring. In addition, as the experience of our research has shown, the identified botanical-geographical relations at the planetary level of vegetation cover can be used to identify dynamic processes in the combination of climate change and anthropogenic impact, through restoration (modeling) the structure and productivity of the original, or indigenous, vegetation cover and comparison with the modern one will allow us to assess the size and trend of these transformations of the plant world. The combined influence of heat and moisture supply determines forest vegetation conditions, which is used for geobotanical, forest vegetation, botanical and geographical zoning, making classifications of forest communities on an ecological and phytocenotic basis, climatic ordination of high-altitude forest vegetation belts, and allocation of high-altitude forest cover divisions.

The method was used in the preparation of maps of ecological and plant complexes that are adequate to correlation geobotanical maps. These results are used in the study of the forest formation process, cartographic modeling of the areas of the original taxa of vegetation cover, optimal places of growth of forest-forming rocks. The obtained research results allow us to draw up multi-level ecological and phytocenotic complexes that combine structural divisions of vegetation cover and higher levels, which are in many respects conceptually similar to the classification of multi-level forest types, They can be used for monitoring tasks not only of vegetation cover, but also in the field of ecological geography, as well as for other tasks. These research results can be used for a wide class of applied problems - in forestry practice (production of forest crops, reconstruction of low-value plantings, etc.), to predict the most environmentally sustainable forest vegetation and its dynamic processes in connection with different scenarios of climate change, and for other environmental monitoring tasks [11,12].

1. Liyev RR (1999) Bioindication of environmental pollution using biochemical and fluorescent parameters of woody plants. Cand biol sciences.
2. Abaturov AV (2007) Forest Woody Vegetation as an Indicator of the State of the Environment. Bioindication of the State of the Environment in Moscow and the Moscow Region, Russia, 97-103.
3. Gelashvili DB (2010) Quantitative Methods for Assessing Air Pollution/Environmental Monitoring. Biological and Physicochemical Monitoring Methods. Publishing House of NNSU, Russia, pp. 1-427.
4. Alekseyev AS (1999) Fluctuations of radial growth in stands under atmospheric pollution. Forestry 2: 82-
5. Balyasova GG, Trofimov VN (1994) Radial Growth of Pine and Spruce in the Forest Parks of the Mytishchi Region as an Indicator of their Condition and Stability. Abstracts of the All-Russian Scientific and Technical Conference, Protection of Forest Ecosystems and Rational use of Forest Resources 3: 33-34