The simplest form of Jammer logging is a set of tongs on the end of a mainline. The yarder can be a shovel, as shown below, or even an A-frame on the back of a truck. However, the shovel jammer can cast the tongsto a log where an A-frame can not. For the A-frame, the brush monkey must be the tongs to each log. This form of logging was very common in the Intermountain area of Idaho and Montana.

A strictly uphill yarding system, the jammer has a reach of 100-300 ft. At its simplest, a single-drum yarder is all that is needed. It can be used in partial and clear cuts. The jammer can also serve as log loader after yarding the logs.

As a side note, the "Bitter Root Controversy" which was one of the first debates over clearcutting on National Forests involved the terracing of granitic hillsides to log them. Since Jammers were used in much of the area, the roads were very close together on the slopes.