Much of the forest, however, has been cut, and the best trees have been taken to the mills and sawed into lumber. Many oak and hemlock trees were cut only to get the bark to be used in tanneries, some of which are still to be found in this region.
The people who cut the forests are often careless in letting forest fires burn up the young trees that remain. Thousands and thousands of square miles have been burned bare of trees. People who wonder why the price of lumber is so high would understand it better if they could see one of these forests that has been burned year after year until nothing is left but the desolate mountain side with little dead trees and a few weak bushes standing upon it. Why might this be called a green desert? The United States Government is now buying some of this burned region and taking care of it so that its forests may grow again.
294. Pittsburgh, a traffic center.—Travel in the plateau is always along the valleys cut by the streams. Otherwise we would be endlessly climbing up one steep side of a valley and down the next side.
One cannot cross the plateau in Pennsyl vania without coming to streams that flow down to Pittsburgh. Thus many river routes come together at that point. That is why the early French settlers picked this place as the site for one of their forts. After the French were driven out, Pittsburgh became a starting point for the flatboats of the early settlers and traders (Sec. 85). When the railroads came, they, too, had to follow the river valleys, and thus Pittsburgh became a railroad center.
295. Pittsburgh, an iron center.—Examine the coal fields map (Fig. 44) and see what parts of this region have coal. Can you tell why Pittsburgh took the lead in coal mining? This city is surrounded by thousands of square miles of rich seams of coal, good for smelting iron. Iron ore is found near by, and also some limestone, which is put into the furnace with the ore to help the melting. Pittsburgh is near to the great cities of northeastern United States. It has de veloped into the greatest iron manu facturing city in the world. It might be called the capital of the world of coal and iron. Along the
river banks, both above and below the city, are iron and steel plants. Some of them have single buildings as large as a field, or as large as several city blocks. Sometimes there is so much smoke that one cannot see across the narrow valley. Each day one of these big plants sends out hundreds and even thousands of tons of rails to be used for trolley and railroad tracks. Many other useful things are made of iron and steel, such as material for bridges, iron pipe, wire fences, nails, and tin plate, from which tin cans and other tinware are made.
296. Iron ore from Lake Superior.—After Pittsburgh was well started at iron-making, it was found that iron could be made more cheaply from the rich ores that had been dis covered near the western end of Lake Supe rior. (Sec.334.) Hundreds of big steamboat loads of this ore are now brought down the lakes each summer, and thousands of cars are busy carrying it from lake ports to the iron furnaces in and near Pittsburgh.
297. Pittsburgh, a manufacturing center. —Other industries have grown up around the steel mills. Pittsburgh and the towns near it have many plants that use some of the iron and steel to manufacture machinery. Sand pits and natural gas (Sec. 301) help western Pennsylvania and northern West Virginia to make much gla-ss. (Sec. 230.) While the men are working in the coal mines and steel mills, many of the women work in the silk mills. This is true in both the anthracite and bituminous coal fields.
298. The soft coal mines.—This rich coal field of western Pennsylvania, western Maryland, and West Virginia has many other towns of the coal-miner. From Pittsburgh and these smaller towns, coal is sent every day by thousands of car loads to New York, Philadelphia, Balti more, New England, and the central states. Carloads of Appalachian soft coal are dumped by machinery into lake steamers at Buffalo, Cleveland, and other lake ports, as easily as a man dumps a wheel barrow. For a very low freight charge, the boats take the coal to Detroit, Milwaukee, and Duluth.