The aim of this research is to develop, construct and evaluate a new-invented system for tree-branches chopping. The chopping system consists of frame, tires, draw-bar, 15-kW electrical motor, feeding, cutting, chopping units and suction-fan. The main results in this study can be summarized in the following points:

The maximum average of chopping length of 19 mm was obtained by using chopping-knives speed of 900 rpm (27.31 m/s), concave-hole diameter of 20 mm and tree-branch diameter of 50 mm. Meanwhile, the minimum average of chopping length of 6 mm was obtained by using chopping-knives speed of 1200 rpm (36.92 m/s), concave-hole diameter of 14 mm and tree-branch diameter of 20 mm (at constant clearance of 5 mm, moisture-content of 10 %, cutting-knives speed of 450 rpm and feeding-drums speed of 10 rpm).
The minimum productivity of 238 kg/h was obtained by using chopping-knives speed of 900 rpm (27.31 m/s), concave-hole diameter of 14 mm and tree-branch diameter of 50 mm. Meanwhile, the maximum machine productivity of 667 kg/h was obtained by using chopping-knives speed of 1200 rpm (36.92 m/s), concave-hole diameter of 20 mm and tree-branch diameter of 20 mm (at constant clearance of 5 mm, moisture-content of 10 %, cutting-knives speed of 450 rpm and feeding-drums speed of 10 rpm).
The operation and production costs at chopping-knives speed of 1200 rpm (36.92 m/s) were 17.42 – 18.71 L. E./h and 28.01 – 68.98 L.E./ton for all tested tree-branch and concave-hole diameters.