Of natural forests — the result of a long evolutionary process. Russian forester GF Morozov (1867-1920) identified the main factors influencing the formation and life of the forest: 1) the properties of the trees themselves, and 2) the conditions of their lives, and 3) the relationship between plants within the forest community, and 4) the effect of the animals, and 5) human intervention. The greatest impact on the formation of the forest, of course, has a climate. But the overwhelming majority of Russian forests grow in the temperate zone, and the differences in their lives is not too significant.
To the north is dominated by evergreen coniferous forests in the south — letnezelenye broadleaf, and everywhere there are mixed. The southern boundary of the forest in the European part of Russia, so far receded from about borders Krasnodar Territory to the latitude of Moscow — the consequences of human activities. Within the same climate zone diversity of forests depends mainly on the composition and moisture content of the soil.
Do trees have different needs: some unpretentious and can grow anywhere, others need a lot of moisture, the third — nutrients. That's why the very poor, dry, or, on the contrary, waterlogged soils are usually formed odnoporodnye forest, and the rich and moderately moist — complex mnogoporodnye.