Page:Popular Mechanics 1928 01.pdf/13

 

last of the great industries to abandon man power has been converted to machinery. Oil and gasoline engines, electric motors and the law of gravity, applied to the forests, have brought out more logs this year than men ever moved before, made of lumbering an organized industry, and left undamaged thousands of square miles of new-growth timber to replace that which men and mules and oxen had trampled into the slopes of our mountains.

An endless-tread tractor, tanklike, but equipped for peace instead of war, rolls into the forest, three men riding it. In the midst of the grove, the great machine halts, a portable saw is unloaded and placed against a towering pine, three feet thick at the base. Power is applied from the engines. In fifteen minutes the tree lies on its side. Again the saw is moved along the log, taking off the branches one at a time. Block and tackle, with a running pulley, is attached to the upper end. A pit is dug at the base. The tractor backs away, picking up the slack in a steel cable running from the top of the fallen trunk to a winch on the front of the machine. The tree rises again, is guyed into place, and becomes what is known among the lumberjacks as a "spar tree."

From its top, or from the top of another high tree, a gang of men, with the aid of the tractor's winches, runs a steel cable to another tree, probably half a mile away down the hill. For a radius of 500 feet around the spar tree, the tractor and its portable saw cuts trees, as a man with a mower might cut wheat. As fast as one falls, it is trimmed and shot down the hill. With two tractors and six men, one California lumber company has cut and delivered, to the pond at the mill, 40,000 feet of lumber a day. Approximately thirty men with four or five ox or mule teams would have been required under the old man-power system, to get out that much timber in two days—instead of one.

When the logs arrive at the base of the mountain—for most of our forests are now on lofty mountainsides—it may be that the mill is still miles away. If there is a large stream, the logs are rolled into 