The traction force during downward felling in the Chamaesyparis obtusa stand was used to measure the resistance forces of the hung-up tree crown while passing between the crowns of the remaining two trees. Moreover, the passing work was calculated using the resistance forces and the moving distance of the crown. The average of maximum resistance forces was 0.91 kN (0.36–1.86 kN), with an average passing work of 1.37 kJ (0.34–3.60 kJ). No clear relationship was observed between the distance of the remaining two trees and the maximum resistance force or passing work, as in previous research, because of the narrow distance between (2–3 m) the two trees. No significant relationship was found between the overlap ratio of tree crowns and the maximum resistance force and passing work. It is suggested that the data be collected over a wider range of crow overlap ratios.

View full abstract