As a countermeasure to the decrease in the numbers and aging of forestry laborers since the 1980s, the Japanese Forestry Agency has been conducting the "Green Employment Project" since 2003. This project aims to recruit new forestry workers and develop their abilities in forestry techniques. A questionnaire survey was conducted on "forest worker" trainees of the “Green Employment Project” in 2013 by the National Federation of Forest Owners’ Co-operative Association. Survey slips were administered to 2,505 trainees after the Off-JT, and 1,839 slips were collected. Evaluations by the trainees based on the responses to the questionnaire were re-analyzed in this study. The results revealed that 1) training in logging and yarding techniques received a high evaluation among the Off-JT contents; 2) OJT received a positive evaluation from almost all trainees; and 3) there was no relationship between the evaluation of the training and the trainees’ background, such as age, former job, academic background, and whether they were locals/settlers. Thus, the design of Off-JT and training framework of OJT by the forestry company are important factors to motivate trainees.

The traction force for removing hung-up trees and the resistance force of crowns was measured in the crowns of two trees by skidding toward the felling direction with upward felling in a steep Chamaecyparis obtusa stand. The average maximum vertical component (T_r1.2) of the traction force at a height of 1.2 m from the butt end was 6.76 kN, and the average resistance force of the crown (F_A) was 1.1 kN. No strong correlation was observed between the interval of the remaining two trees (D) and the T_r1.2 or F_A value. A power relation was shown between the overlap ratio of the crown (R_c) and the F_A. The upper limits of the T_r1.2 and F_A values were expected according to the D value. Compared to other studies, the values of the upward felling and traction force toward the felling direction found in this study was greater than the downward felling and traction force toward the felling direction. The latter were approximately equal to those of the downward felling and butt-end traction but were greater than the ones of the upward felling and butt end traction. Our results demonstrate the difficulty of manpower methods using rope-based stem traction toward the felling direction and butt-end traction in the direction opposite to felling.

To assess the safety of cutting the butt log at removing hung-up trees occurring in crowns of two trees, an experiment was conducted that consists of cutting step-by-step the butt log of hung-up trees in Chamaecyparis obtusa stands. Of 44 hung-up trees in total, 16 were felled successfully as planned, whereas 15 hung-up trees were felled in a direction perpendicular or opposite to the planned direction. In 13 cases, the tree did not fall. Hung-up trees fell in directions perpendicular or opposite to the planned direction when the angle of a hung-up tree with the horizontal plane was >60 degrees. We compared 1) the method of moving the butt end to a position opposite to the felling direction by traction and 2) the method of cutting the butt log. The results showed that the moving distance of the butt end on a slope did not differ. The success rate of method 2 was a little over 30%. Furthermore, the removal rate remained up to 70% when instances of felling in directions perpendicular or opposite to the planned direction were included. Thus, superiority of the method of cutting the butt log could not be confirmed.

J-SACL was conducted on a total of eight forestry workers (four females and four males) to clarify the physical, psychological and social stress states of such workers for contributing to the spread of forestry worker education and forestry technique. The investigation revealed that stress levels of the participants were low, while arousal levels were high. Stress levels were significantly lower than those of general adults and the risk of stress-related diseases was low. Stress levels measured after forestry operations tended to be lower than those before those operations. Although the existence of psychological stress from mechanized work was pointed out in previous studies, there were no such signs in our work. This may be because the workers were not only affected by mechanized operations but also by other manual labor during the study periods. A comparison of our results with those in other fields shows that stress levels of forestry workers in this study were equivalent to those of urban college students who had undergone stress relaxation training.