Ecological functions of forest stands in urbanized environment of Moscow

In urban forests, stock production is not the main function of stands. Carbon sequestration, the release of oxygen and phytoncides, dust precipitation, and changing wind conditions et al. are the main environmental functions. Phyto-organic substances emitted by trees help to reduce the number of microorganisms in air make the air cleaner and fresher. The purpose of the study is to evaluate the ecological functions of forest stands based on long-term observations of the forest stands of the Forest Experimental District of the Russian State Agrarian University - Moscow Timiryazev Agricultural Academy. The study used data about 7 permanent trial plots in natural pine stands, 7 - in pine plantations (planting density - 32 000 trees per 1 ha), 13 - in larch plantations (planting density - 700-4000 trees per 1 ha), 8 - in oak stands (natural stands and plantations) and 9 - in birch stands (natural stands and plantations). For a year, 1 ha of forest covered area produces 10 tons of oxygen, and the entire territory of the Forest Experimental District produces about 2.5 thousand tons of oxygen. In the year, the stands of the Forest Experimental District absorb about 3 thousand tons of carbon dioxide. The forest stands of the Forest Experimental District are capable of precipitating 135 tons of dust and they emit about 130 tons of phytoncides into the air during the growing season. Under urban conditions, forest stands are subject to the influence of negative factors: emissions from industrial enterprises and transport, recreational loads, disruption of natural conditions, and many others. Negative factors lead to a decrease in the performance of ecological functions. Therefore, in urban forests it is necessary to carry out silvicultural measures to increase the sustainability and productivity of stands.