PrairiesTo the west of the eastern forests the climate becomes drier, and forests give way to grass. The steppes of North America are called prairies. They are covered with high thick grass. Nearer to the Rocky Mountains the grass is shorter. Before the coming of the Europeans the bisons used to go over the grasslands and they were hunted only by the Indians. Early Europeans began the thoughtless
Welcome to the USA!
destruction of the animals because of their skin. Now only a few are left in parks and Zoos. To the Europeans going westward out of the Eastern forests, the grasslands put a question – why were there no trees? Indeed, except along the banks of rivers, there are no trees – until they are planted by farmers. The answer at first seemed simple; there just wasn’t enough rain or it did not fall at the right times of the year to allow trees to grow. It is true that in the western grasslands the rainfall is too little for the growth of most trees. But this is not the whole story. Clearly something else did not allow trees to grow and that something was grass. The explanation lies in the characteristics of grass plants themselves. Their roots grow at a very great speed. One grass plant gives hundreds of miles of roots in only a few months. Those roots will prevent any tree from growing in the same place. Besides, the grasses take the water and no water is left for the tree. An important factor was the bisons, which broke many young trees. One of the reasons was fire. Fires began during the storms or were started by careless people. Though the parts of the grass which are over the ground are burned, their roots are not in danger when the rains come the following spring they begin to grow again. On the other hand, fire is very dangerous to the trees. The Rocky Mountains influence the grassland in still another way: they are a high barrier to wet winds blowing inland from the Pacific Ocean. Close to the mountains the grasses are short but in the open prairie it grows – or once did – higher than the head of a man. Today the prairies are almost completely destroyed. As the economy developed, more and more natural grassland was used for farming.
Vocabulary: 1) Bison ['baɪsn] - бизон 2) Careless ['kɛələs] – небрежный; беззаботный 3) Destruction [dɪ'strʌkʃ(ə)n] - уничтожение 4) Give way to – уступать, давать место 5) Prevent from doing smth. [prɪ'vent] – мешать, препятствовать 6) Steppe [step] – степь
Welcome to the USA!
|
