In the Ukraine, the borders of three main divisions of plant-geography of Europe meet—the Mediterranean division, the steppe region, and the forest region, with their transition regions. Besides, we meet in the Ukraine three mountain regions—the Carpathian, the Crimean, and the Caucasian. In respect to flora, the Ukraine possesses only a few endemic species. To be sure the great ice period covered only comparatively small areas of the Ukraine with its glacier, but the polar flora undoubtedly prevailed in the entire country at that time. After the withdrawal of the glacier, steppes first appeared in its place, which then, especially in the Northwest, were forced to make room for a forest flora that had immigrated from Central Europe and Siberia. Hence, despite the considerable area of the Ukraine, so few endemic species.
Since those primeval days, only a very few natural changes have occurred in the vegetation of the Ukraine. However, man, thru his cultural activity, has wrought many changes in the plant-world of the country.
The forest region occupies barely one-fifth of the Ukrainian territory, only the northwestern and northern borderlands. The southeastern border of the forest region [[100]]extends from the Prut and Dniester on the western boundary of Pokutye and Podolia in a curve to the source of the Buh, then near the northern boundary of the Dnieper Plateau east as far as Kiev, and thence toward the northeast as far as the source of the Aka. This boundary, however, is not sharp. In numerous peninsulas the compact forest penetrates the adjacent transition region toward the southeast. On the other hand, this forest boundary coincides almost exactly with the northern boundary of the black soil. The soil of the forest region is in general poor. Only in higher places we find fertile turf; beyond that sandy soil and the podsol, rich in quartz, predominate.
The prevailing plant formation in this region is the forest. It once covered the entire region and was thinned to any great extent only within the last two centuries. What these primeval forests were like we can now tell in only a few districts of the Polissye and in the famous virgin forest of Biloveza, which lies in the extreme northwest corner of the Ukrainian territory. Here we see the primeval forest in its mighty size and beauty. In wind-fallen woods, several meters high, rotten, decaying stumps cover the ground. Their roots stand up high into the air above swampy holes and vast masses of rotting remains of plants. Above this swampy fen rise, like a vast mass of pillars, the knotty trunks of century-old oaks and lindens, ash and aspen, and the slender pine and fir. High above the ground their branches intertwine. All strive up toward the sun, for a continuous semi-darkness reigns below. Shrub and herb vegetation thrives only in clearings; beyond that only last year’s leaves, needles, and a mysteriously glowing decay cover the ground. Dead silence, only occasionally broken by the hammering of a woodpecker or by the timid voice of a bird, reigns everywhere, making all the more impressive the mighty roaring of the lofty crowns in the storm. [[101]]
As to their composition, the woods of the Ukrainian forest region are mixed, altho local conditions cause one or the other species of tree to predominate. The Ukrainian forest region may be divided into two regions by a line running thru Lublin southeast toward Lutzk. Southwest of this line extends the Central European forest zone, northeast of it the Northern European forest zone.
The Central European forest zone embraces the entire Pidhirye in the Ukraine, the southern part of the Rostoche, and the western spurs of Volhynia and Podolia. It is distinguished by a greater variety of tree species. Here, upon damp, loamy hills, entire forests of beech are found, on the Carpathian foothills the pine, and singly or in small groups, the larch, the yew, the maple, etc. In the Northern European zone all these trees disappear, due to the increasing continentality of the climate. The predominating species of tree here is the pine, which forms large woods everywhere on sandy soil, then the birch, which always accompanies the pine, the fir on sandy soil, the oak and white beech on loamy soil. There is an admixture of a considerable number of alders on swampy ground, aspens, lindens, elms, maples, ash and wild apple, pear and cherry trees. Hazel bushes, willow (salix caprea), mountain ash, raspberry and blackberry bushes comprise the thick underbrush in these mixed forests, and contribute a great deal to the beauty of the woods, together with grass and herb vegetation, especially in numerous clearings. In truer evergreen forests the underbrush usually is very poor.
There are a great many swamp forests in the Ukrainian forest region. In the Carpathian foothills they are called lasi, and are quite common there, but in the Polissye they are most widely developed. There they are usually composed of pines, with which, however, the swampy ground does not agree very well. The alders and willows, however, grow all the better. [[102]]
The second important formation of the forest region are the luhi. They usually stretch thru the wide, flat river valleys of the region. These are luxurious meadows with a beautiful growth of grass and herbs set with single trees and clusters of trees. In dry places the oak usually grows, in damp places the alder.
The third typical plant formation is that of the swamps. They are widely developed in the forest region of the Ukraine, especially in the flat river valleys of the Rostoche and Volhynia. Polissye is the greatest swamp country in Europe. Regular moors, made up of peat mosses, alternate even in the Polissye region with meadow moors, in which swamp grass and herb vegetation predominates.
The forest region has played a significant part in the history of the Ukraine. When the Turkish nomad tribes, using the steppe district of the Ukraine as a convenient military road, destroyed the work of Ukrainian civilization in the steppe region, the Ukrainian people retreated into the forests and swamps of the north and west, advancing toward the southeast again, at the proper moment, to reinhabit the ravaged and desolated lands. This circle of events repeated itself frequently in the history of the Ukraine.