Log driving is a means of log transport which makes use of a river's current to move floating tree trunks downstream to sawmills and pulp mills.
It was the main transportation method of the early logging industry in Europe and North America. When the first sawmills were established, they usually were small and were established at temporary facilities near the source of timber, then moved to new areas as the timber supply was exhausted. Later, bigger mills were developed that were not as portable, and these were usually established in the lower reaches of a river, with the logs brought to them by floating downriver by log drivers.
To ensure that logs drifted freely along the river, men called "log drivers" were needed to guide the logs. This was an exceedingly dangerous occupation, with the drivers standing on the moving logs and running from one to another. When one caught on an obstacle and formed a logjam, someone had to free the offending log. This required some understanding of physics, strong muscles, and extreme agility. Many log drivers lost their lives by falling and being crushed by the logs.
Log drives were often in conflict with navigation, as logs would sometimes fill the entire river and make boat travel dangerous or impossible. On small tributaries logs could only be driven during the spring flood, when thousands of logs, cut during the winter months, were sent downriver. Each timber firm had its own mark which was placed on the logs. Obliterating or altering a timber mark was a crime. At the mill the logs were captured by a log boom, and the logs were sorted for ownership before being sawn.
Log driving became increasingly unnecessary with the development of railroads or the use of trucks on logging roads, however, the practice survived in some remote locations where such infrastructure did not exist. Most log driving in the United States and Canada ended with changes in environmental legislation in the 1970s. Some places, like the Catalonian Pyrenees, still retain the practice as a popular holiday celebration once a year.