This article presents the factors influencing the formation and viability of woody vegetation in the forests of Penza region, located at the border of broad-leaved forests zone (north-eastern part) and forest-steppe (west-ern half and south-eastern part). According to the results of the National Ecological Rating of Regions, Penza region ranked 28th out of 85 Russian regions where environmental pollution is monitored. The total land area of forests is 999.3 thousand hectares, or 23.0% of the total land area of Penza region. Operational forests occupy 413.1 thousand hectares or 45.1% of the total area of land area of forest fund. Protective forests occupy 502,100 ha or 54,9% of total area of lands of forest reserve. Coniferous (pine, spruce), soft-leaved (birch, aspen, linden, alder, willow, poplar) and hardleaved (oak, ash, maple, elm) forest plantations grow on the territory of Penza region. The predominant and main tree species are Pínus sylvestris, Quercus robur, Betula pendula, Populus tremula, Tília cordata and Fraxinus excelsior. Every year, the region’s forests are affected by abiotic, biotic and anthropogenic factors. As a result of these processes there is a weakening of trees and their increased retreat in the plantation. Among the range of negative impacts on the condition of the region forests the first place is occu-pied by forest diseases (68,9% of the total area of all the negative factors), the second place - by weather condi-tions and soil and climatic factors (22,2%), the third - by forest fires (7,7%). In general, the condition of forests in Penza region is satisfactory. The most important task of forestry is to increase the productivity and quality of forests.

Abstract. This paper presents data on characteristics and extent of degradation of soil quality, atmospheric air and plants in urban and suburban areas of the Lower and Middle Volga region, Central Chernozem region. The goal of the research is to analyze and present data of environmental monitoring of soil, atmosphere and plants. On the example of the Saratov, Voronezh and Penza Regions, the values of the state of terrestrial ecosystems on different types of soils are established. The predominant position in terms of area and economic use is occupied by soils transformed in the course of urban development, as well as artificial soils. Compaction, anthropogenic inclusions, littering and heavy metal contamination are of great importance in the degradation of the soil cover. In the air-technogenic pollution, the formation and deposition of dust on the leaf surface of plants plays a significant role. Bioindicative signs in the analysis of the state of the environment and ecological systems were indicators of the viability, condition and stability of trees and shrubs. They are obtained based on average data from the research and subsequent assessment of life status. Separately, the indicators of degradation of woody plants assimilation organs depending on the levels of unfavorable soil-ecological and aerogenic conditions in urban and suburban ecosystems of the studied regions are considered. The significance of degradation of environmental objects by analyzed anthropotechnogenic factors is reflected in the correlation analysis results.

Currently, wood is used as an ecologically friendly type of fuel. But its supply is limited due to the long period of forest restoration. That's why looking for alternative sources of energy on non-wood origin, which would make a decent competitor to wood in terms of biomass growth speed, is an urgent task. Penza region has great possibilities for organizing plantations for cultivation of energy fast growing herbage plants with high content of cellulose on noncrop lands. One of the promising steps in this direction is the introduction of perennial Miscanthus giganteus into agriculture. For its introduction into the yielding, it's necessary to define the productivity and calorific capacity of Miscanthus. The peculiarities of plant growth in relation to local climatic conditions were discovered and the correspondence of the culture to the local moisture conditions was defined. In the year of plantation establishment (2013) on the light-grey soil at the excessive moisture, 14t/ha of top was received. A good development of yearlings increased their winter hardiness and the productivity of Miscanthus doubled the next year. Despite the arid conditions, in the third year of research, it increased by 7 t/ha as compared to the previous year. The fourth and fifth year of Miscanthus life were the most productive (40 and 41 t/ha) because they corresponded to the level of 2013 in terms of moisture conditions. The productivity of plantation in hyper arid 2018 and 2019 decreased to 30 t/ha. According to the main ecological and energy characteristics, chips from the stems of a seven-year-old Miscanthus meet European standards.

The main raw material for the production of cellulose is wood, which is also used as fuel, but it takes at least 80 years to regenerate forests. Therefore, it became necessary to find other possible sources of energy and cellulose. Miscanthus giganteus could become a possible and efficient renewable raw material. It also could replace forest crops in several ways. In this regard, in the Middle Volga region, which belongs to the zone of unstable moisture, the current research has been carried out since 2013 on the application of Miscanthus giganteus in light gray soil. Well-formed plants in the year the sowing with sufficient moisture provided the yield of the aboveground mass of 14 t/ha, in the second year it increased 2 times, in the third, despite the arid conditions, it reached 36 t/ha. The next two years were the most productive, when, with sufficient moisture, it was received 40 and 41 t/ha. In the severely arid years 2018 and 2019, it decreased by 9 and 11 t/ha, respectively, in relation to the fifth year of growing. The growing season of the last two years was favorable, but precipitation fell earlier or later than the critical phases of Miscanthus giganteus growing, which led to a decrease in yield to 25 t/ha. On average, per year, starting from the second year of growing, it could form 32 t/ha of energy biomass, which in terms of cellulose content, depending on the age of plants, is equal to wood (48.10-59.81%), and in terms of calorific value, raw materials correspond to the European standards.

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