Several centuries ago the coniferous forest covered all of Canada (except for the northern fringe), Europe, and northern Siberia; at the same time the leafy hardwood forest occupied eastern United States, the temperate zone of Europe (from England and France to Poland), and southeastern Siberia.
The pine forest is poor in secondary vegetation: families of birches, blueberries, bushes, and little grass. On the contrary, the hardwood forest (oak, beech, and chestnut) is one of the richest of environments. Vegetation grows at several levels: treetops, shrubs and bushes, mosses, and humus. The hardwood forest offers animal life moist protection from heat, dried vegetable matter as shelter from cold, and abundant food. Each level has its inhabitants. In the humus are swarms of protozoans, rotifers (small water animals), worms, wood lice and other bugs, mites and ticks. These life forms live on dead vegetable matter which they transform into fertile soil. The second level, the ground surface, belongs to ants, snails, land mollusks, and other small animals on which toads, porcupines, hedgehogs, lizards, and birds feed. In the grassy borders of the forest are found many small grass-eaters (rabbits and field mice) and the animals that prey on them (weasels, martens, cats, and bears). Each animal needs its particular food; wild boars dig in the humus; deer look for tree bark, plant shoots, and leafy shrubs. The high trees are the realm of climbing nut- and fruit-eating animals (squirrels and dormice) and their predators (martens); this is also the home of tree-dwelling birds.
Greatly reduced by man, the hardwood forest, now exists in its natural state only in the taiga of southeastern Siberia. The deforestation of Europe resulted in much soil erosion, and reforestation has been under way for about 100 years. un-fortunately the plantings have consisted of fast-growing coniferous forests, whose acid humus is not suitable for the development of undergrowth. These forests, with their zoological void, are spreading to the south and pushing out such hardwood forests as remain, along with their diversity of animal life.
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