Anyone who has ever tried building fireline on rocky land knows there has been a need for an inexpensive, efficient piece of equipment to do this job. We've recently invented a simple fireline plow to build fireline in such terrain. Fireline construction with this plow makes less of an impact on the environment, and it may cost less than usual methods of building line (either by hand or by machine). In March and April 1994, we conducted underburning on 35 acres (14 ha) in a private forest in western Montana, mainly consisting of ponderosa pine and Douglas fir. Our objectives were to reduce surface fuels, kill stagnated and rust-infected saplings, and remove dense, undergrowth to allow healthy pine regeneration. We had only three workers available, we needed to burn in divisions on 3 or 4 days, and we had to provide our own equipment at low cost. The terrain is gently sloping but rocky and difficult for hand fireline construction. Our task was to construct 1.5 miles (2.4 km) of fireline through almost continuous boulders that support a dense mat of low, woody vegetation (largely kinnikinick) and pinegrass. We considered alternatives, then decided to construct a fireline plow that could be pulled by a small farm tractor. From a scrap metal yard, we purchased some promising components for 10 cents a pound (454 g), then took them, along with our ideas, to a local blacksmith. After only a little experimentation and for only $150, we had it-a plow that makes good fireline even in rocky glacial till.