Abstract
Forest cleaning, being an operation that requires investment, but the return on investment is due for the next generations, utilizes tools and methods that mostly haven’t been humanized. Harmful vibration is still present in today’s forestry operations, and new tools provide possible reduction of exposure to vibrations. Petrol chainsaw and battery chainsaw (late cleaning) and billhook, machete, and battery shears (early cleaning) were used and observed in this study. Vibration levels were measured and assessed using validated Brüel & Kjær 4447 vibrometer which complies with the ISO 8041:2017 standard. The measurement was performed according to the recommendations of ISO 5349-1:2001 and ISO 5349-2:2001 standards. Vibration exposure was assesed using work sampling method on the obtained video recordings in order to calculate relative shares of different work elements. Results show that hand tools (machete and billhook) are causing the highest vibration levels, while battery shears cause the lowest. Battery chainsaw causes higher vibration levels while cutting, but lower daily vibration exposure than petrol chainsaw. A detailed revision in the classification of tools is needed, considering their ability to produce and transmit harmful vibrations to the operator. Using the current classification, the daily exposure to vibration of workers in early forest cleaning is high above legislative values.