LOGGING

process of harvesting trees, sawing them into appropriate lengths (bucking), and transporting them (skidding) to a sawmill. The different phases of this process vary with local conditions and technology. In the 19th century logging was a hand process, and in some parts of the world it has remained one. In colder regions, trees are felled by ax in winter and conveyed by a sled drawn by oxen, mules, or horses to a frozen river. After the spring thaw, the logs are floated downriver to a sawmill. In mechanized modern logging, trees are felled by crosscut saw or power-driven chain saw or, for trees of relatively young plantations, by a machine that cuts the entire tree in one bite. Trees are then cut into standard lengths and skidded to the mill by truck or tractor or conveyed to a central point by cable, either high above ground (high-lead and overhead skidding) or along the ground (groundline skidding). Helicopters and balloons are also used to transport logs. Local conditions may dictate uncommon logging methods. In India, teakwood trees are killed by girdling (making a circular cut around the tree through the outer bark and cortex to interrupt the circulation of water and nutrients) and harvested several years later. Then, as is also common in Nigeria, they may be floated down the river by raft. In several Asian countries, timber may be transported by elephant. See also forestry.