Assessment of hand-arm vibration levels/exposure during motor-manual tree processing with the MPTMGS5803 chainsaw model

Chainsaws, which are widely used in tree felling operations, create vibrations. Long-term and intense exposure to vibration may lead to the development of vascular, neurosensory, and musculoskeletal disorders in the upper limbs of chainsaw workers, known as Hand-arm vibration syndrome. This study investigates the vibration levels during tree bucking operations on poplar trees with the MPTMGS5803 chainsaw model, one of the most widely used chainsaws in forest operations in the western part of Guilan province. Simultaneous vibration measurements in three directions (x, y and z) were carried out using the SVANTEK 106A vibration meter, aiming to determine the total amount of chainsaw vibration and the daily exposure period. The results show that the highest amount of vibration was measured in the x (1.61±0.62), (2.01±0.90) direction and the lowest in the y (1.48±0.17), (0.73±0.09) direction both in the rear handle and front handle of the chainsaw. The rear handle of the chainsaw had a higher overall vibration acceleration (3.05±0.54 m/s2) compared to the front handle (1.94±0.53 m/s2). In terms of the daily exposure period, the level of vibration exposure inflicted on the chainsaw operator during a  three-hour and 70 second working period amounted to 1.19 m/s2 in the front handle and 1.87 m/s2 in the rear handle, with both values falling within the permissible vibration range.