Cornelis Corneliszoon van Uitgeest or Krelis Lootjes was a Dutch windmill owner from Uitgeest who invented the wind-powered sawmill, which made the conversion of log timber into planks 30 times faster than before.

A sawmill or lumber mill is a facility where logs are cut into lumber. Modern sawmills use a motorized saw to cut logs lengthwise to make long pieces, and crosswise to length depending on standard or custom sizes. The "portable" sawmill is simple to operate. The log lies flat on a steel bed, and the motorized saw cuts the log horizontally along the length of the bed, by the operator manually pushing the saw. The most basic kind of sawmill consists of a chainsaw and a customized jig, with similar horizontal operation.