Lum′bering, an industry of great importance in the United States, Canada, Russia, Scandinavia, Germany and France, is the process of cutting and sawing timber for purposes of building and furnishing. In the United States there was more than $500,000,000 invested in lumber and timber-products in 1912. Those employed numbered over 400,000. The value of the products was upwards of $550,000,000. It is not only the direct production of lumber that counts; but large profits are made from by-products. Sawdust is sometimes compressed and heated until it may be molded into a solid mass of any required shape. In Norway it is distilled to afford acetic acid, tar and wood-naphtha. The best wood-alcohol is obtained from pine sawdust. Woodpulp is in ever increasing demand for the manufacture of paper. The lumber industry, properly so called, is divided into three branches, each of which represents a group of distinct operations. Logging is felling and roughly trimming timber and transporting it, preferably by water but, if necessary, by rail, to its destination. The great rivers of the United States afford unequalled opportunities for logging. Whenever possible, the logs are fastened in huge rafts and navigated down stream as the current and volume of the river may permit. Then comes the sawmill branch of lumbering. The logs are sawn into beams and planks, but not carefully trimmed. The planingmill stage is that in which the beams and boards are trimmed and manufactured to standard dimensions and uses. In lumbering the principal difficulty always is transportation. At times in the winter the roads are flooded and frozen for the readier transportation of logs. In connection with lumbering arises the national problem of how to conserve the forests. Great as are the forests of America, they cannot supply the present enormous demand. Many forests have been totally cleared. In 1912, according to the bureau of the census and the forest-service, over 40,000,000,000 feet were cut. The actual cut is believed to have been five per cent. larger or 2,000,000,000 feet more. Efforts are made by the United States Bureau of Forestry to conserve great forest-parks and to plant young trees. Treeplanting by school children and by individual citizens is and ought to be encouraged. See Forests.