Physical effects of hinges shape on chainsaw felling direction in Japanese Cypress

ABSTRACT

In Japan, most felling operations are performed manually with chainsaws, owing to the steep and difficult terrain involved. The average productivity per worker is approximately 5 m³ per day, and accident rates remain constant, with 57% of fatal accidents occurring during felling operations using chainsaws. These accidents were caused primarily by unpredictable felling direction, which typically results from unevenness of the hinge cut into the felling surface. The authors performed a pulling experiment using wires to clarify the physical function of the hinge during manual felling operations. They found that when the hinge was uneven, a moment was produced toward the thicker side of the hinge and increased as the hinge surface area increased. Consequently, a larger, uneven hinge shifts the actual felling direction away from the optimum direction.

KEYWORDS:

• Height of back cut
• hinge area
• hinge shape
• moment
• pulling experiment

Acknowledgements

This work was supported by the Japan Society for the Promotion of Science (JSPS), under the Bilateral Cooperative Research Program with Bogor University, Indonesia.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This project was supported by JSPS Bilateral Open Partnership Joint Research Projects.