Roller choppers are large drums with a series of longitudinally mounted blades. As the drums rotate they chop and crush brush debris, small trees, and slash. They also form small trenches or pits in the soil to capture rainfall, increase infiltration, and provide a seedbed. The drums are hollow and are usually filled with water to increase their weight and chopping action. Drum diameters vary from 24 to 60 inches. Choppers can be pulled in single, duplex, triplex, or tandem configurations. Width can vary between 5 to 16 feet, and required horsepower for pulling varies from 60 to 350.
Roller choppers are effective in forest site preparation. They are also popular for treating brush species that produce regrowth valuable for goats and wildlife. Choppers can cut brush up to 5 inches in diameter. They should not be used in rocky soils. The faster choppers are pulled the more they bounce, increasing chopping effectiveness, but the vibration is detrimental to the equipment. Hitches often use springs to absorb the vibration. A popular variation in blade pattern is a spiral-blade chopper, often called an aerator or renovator. Models called “land imprinters” use wedges rather than blades to form depressions in different directions to decrease runoff and increase infiltration.