The US Flora (2196)
The USA is very rich in plants and trees. About 1/3 of the country is forest land, ј is grassland pasture, and 1/7 is active cropland. The forests include pine, oak, maple, birch and chestnut.
Two centuries ago the eastern part of North America was thick forest. Today the civilization has left less than 25% of the district in the forest. We can still find small districts grown with longleaf pine forest in Florida. One can hardly mistake this tree from any other. For the first six or seven years of its life, the tree hardly grows at all, and its needles are like a little bush of grass. But during this time large roots are growing underground. Afterwards the part of the tree which is over the ground begins to grow. The bright-green needles of a large tree are a foot and a half long. They make this pine one of the most beautiful of all the pines.
Compared with the leaf-bearing forests of Europe, those of North America are richer. There are more kinds of trees. The main trees are oak and chestnut, but of a different kind than in Europe. The live oak is often two times as wide as it is high. Its oval leaves also are unlike those of most of the northern oaks, and they stay green the whole year. The tree was good for shipbuilding and the greater part of the oak forests was thoughtlessly destroyed. Some of the old oaks are still found in the southern lowlands.
There are trees in North America that one cannot find in European forests: tulip-trees and sugar maple.
The forests of the Pacific Coast were a bushy forest with grass from southern California to San Francisco and an evergreen forest of sequoia trees in some places. The great fogs lie along the Pacific coast from northern California to Alaska during spring and summer. Where this fog district lies in California, it allows very tall sequoias to grow. They are also called redwood. In fact, redwoods are not found father than the fog district. And the very place where sequoias grow shows that sea fogs come there. The big size of redwood surprised the Spaniards. They said that eight men holding hands could not form a circle around one of them. When it was later discovered that these trees were very good building material their cutting began at once. European settlers destroyed the northern and central forests of the United States by cutting and fire. Today only a small number of sequoia trees remain. These trees are very high and are the oldest things on earth. The redwoods of California reach 300 ft high and more. The cutting continues even today. Even the small number of sequoia trees which was left in state parks is in danger because of highways planned to go through these forests.
***
Дата добавления: 2015-05-26; просмотров: 1166;