National Geographic : 1939 Jan
Photograph courtesy Caterpillar Tractor Co. WHEN THE FOLLOWERS OF DANIEL BOONE CLEAR LAND TODAY, THEY "SWING" TRACTORS INSTEAD OFAXES Since the beginning of the twentieth century nearly half a million acres of mesquite, brambles, and cacti havebeen cleared with axes and picks. Now heavy tractor-driven "clearing machines" crunch through the remaining patches of jungle, as here near La Villa, preparing theground for orchards and gardens. Aheavy arm, or bumper, extending in front, pushes trees over. A gigantic plow, like a locomotive's cowcatcher, noses under andthrough thestraining roots and scrapes away the smaller plants, leaving clear ground behind. Such a machine can strip the brush from two acres each hour (page 74).