The constructional parameters of the drum chipper are the following: forms and sizes of points regarding the feeding table, sizes (diameters) of the upper and bottom pulling cylinders, the forms and sizes of the points on the upper and bottom pulling cylinders, the chipping drum’s diameter, the chipping drum’s weight, the number and positions of the knives within the chipping drum, the chipping knives’ sharpness angles, the counter blades’ sharpness, the sizes and forms of the sieve rifts, and the forms of the discharge fans etc