Abstract: A size-reduction apparatus, especially for twigs and branches of trees and shrubbery is disclosed. The apparatus is provided with a loading chute, a chopping chamber having a chopping blade which rotates about a vertical axis, a shredding chamber having a cutting blade which rotates about a vertical axis, a feed tube which opens into the shredding chamber, a drive motor, and a respective discharge chute or conduit for each of the shredding and chopping chambers. The chopping blade and the cutting blade are driven separately by a respective shaft, and the chopping chamber and the shredding chamber are disposed next to one another.