With four types of chain saws; two Chinese-made high-handle chain saws(GJ85 and 051), Chinese-and Japanese-made low-handle chain saws (YJ4 and E580), simulated tests of felling and bucking operations in the laboratory and carrying operations on the forest road were performed by three subjects. The heart rate (HR) and integrated electromyogram (IEMG) of the subjects were measured during these tests, and operational characteristics and problems of the high-handle types were discussed. On condition that the weight of the four types were unified, operational characteristics of the high-handle types were summarised as follows: In the felling operations, the HR and IEMG of subjects with GJ85 high-handle type were not greater than with the low-handle types, i.e., the high-handle types showed excellent characteristics because they could be operated in standing posture, and be grasped with nearly even force of both hands. But in the bucking operations, GJ85 high-handle type did not show such excellent characteristics as in the felling. In the carrying operations, there were significant differences in IEMG of the high-handle types (between GJ85 type and 051 type), because of the structural differences of their handles in grasping. As for the Chinese-made high-handle types used in this study, their weights and cutting performances were inferior to the Japanese-made low-handle types, and their future improvements were necessary.

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Analyzing the accident reports of forestry work, we found that there are significant relationships between certain accidents such as "Fall" and "Mishandling", and the forestry workers' decreasing movement abilities with age such as "Agility" and "Balance" and so on. Results from the physical fitness tests showed that the forestry workers' "Muscular endurance" (maximum oxygen intake) and "Muscular strength" (grip strength) decrease at a lower rate with age than those of Japanese standards; however, the motion abilities such as "Balance" (close-eye foot balance) and "Agility" (jumping reaction time) decrease at a faster rate with age than the Japanese standard. An investigation of a questionnaire given to the advanced-age forestry workers showed that the abilities of "Seeing", "Hearing", "Writing speed" and "Memorization" decrease at a faster rate with age while that of "Muscular endurance", "Muscular strength of leg" and "Flexibility" decrease at a slower rate with age. Based on the study of the relationships between the human motion ability and the result from the analysis of the movement of feet, hands and waist, the range of angle and the angular velocity between backbone and leg, and between arm and backbone, we could conclude that the physical motion in piling and felling the trees, among various physical activities in forestry work, highly requires the physical abilities such as "Balance" and "Agility", yet these traits weaken with age.

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Time studies were done for thinning operations with a Mobile Tower-Yarder. Operational elements of time and productivity of the logging operation were analized. As a result, the average yarding volume of the logs skidded with the upper-yarding cable and the lower-yarding cable were 35.4m^3 and 64.8m^3 per day, respectively. The total logging volume of the upper and lower-yarding was 22.8m^3 per day. We found that it is efficient to yard with the use of the lower-yarding cable 33 times per day after using the upper-yarding cable 34.5 times per day. The average yarding volume would be 26.4m^3 per day if yarding had been done with a one-step logging operation system; therefore, we could yard 15.8% more per day with a one-step logging system than with a two-step logging system.

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This experiment involves a newly developed measuring system of the ground surface. The new system can measure the relative distance between the sensor and the ground surface, and it can easily record the profile data using a personal computer. In this experiment, we analyzed the measurement error of the laser sensor, onforest ground surfaces. It was found that the measurement error was less than 2mm throughout the measuring range of the laser sensor. It was also found that there was a relationship between the measuring error and the wetness of the ground surface; however, no relationship was found between the measuring error and changes in the ground surfaces colors. Results from the actual trial of the prototype device demonstrated the potential of the newly developed measuring system.

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When heavy machines are used for harvesting operations and road building on steep terrain, deliberate consideration and planning are necessary to protect environmental conditions. In this study, we studied the various road spacing of the mini-forwarder to minimize the total costs of forwarding operations (C_f), the construction of sediment control embankment (C_<e1>), and vegetation of cut slopes (C_<e2>). On a slope of 30 degrees the road spacing that minimizes the total costs was 17m for C_f, 21m for C_f+C_<e1>, and 31m for C_f+C_<e2>. On the condition that C_f+C_<e2> was minimized, the productivity decreased from 2.87m^3 per hour to 1.99m^3 per hour while the total cost increased from 1,500 yen per m^3 to 2,990 yen per m^3. The result suggests that the mini-forwarder operations on dense road networks should be avoided on steep terrain.

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In 1990, the Indonesian government began a trial to obtain workers for the industrial forest plantations in East Kalimantan by moving people in the overpopulated Jawa island to the underpopulated East Kalimantan. The objectives of this research were to study how people accepted this transmigration trial and whether we could predict their acceptability of the transmigration in advance. We used questionnaires in this study. We classified their acceptability into four levels based on the degrees of their satisfaction of work and transmigration. The canonical discriminant analysis was used to analyze the data. As a result, the canonical variates form 1st to 3rd were significant at a 5% level. The first canonical variate showed the degrees of satisfaction with work, and the second canonical variate showed the degrees of satisfaction with the transmigration. The discriminant ratio was 64.6%. Studying the data before transmigration in a similar manner, we obtained a discriminant ratio of 60.8% and the four levels of acceptability were grouped into four quadrants. Based on this study, we believe that there is a possible way to predict people's acceptability of a transmigration.

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The road roughness has an influence on the forest road maintenance for forest conservation. Depression's especially, have influences in the drainage of the road surface and the bearing capacity. We should except a certain amount of time in maintaining forest roads. We took the leveling with a section of 20m on forest road of Niigata University Forest in August, 1991 and an asphaltic road in March, 1994. We then divided the section 20m into 10 parts and drew figures and measured the size and the depth of the depression with each part of the figures. We also evaluated the forest road surfaces with a data of 175 above the sea level. The result, based on the size and the depth of the depression obtained was about 99 cm in size and about 10 mm in depth on the better road surface. The worst road surface was about 90 cm in size and about 20 mm in depth. In the power spectral analysis, we obtained a 3.45 cycle/m of the frequency with the better road surface and the worst road surface was 5.2 cycle/m of the frequency.

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We studied the usage conditions and user on a pruning machine <AB230R> by a survey method. We received approximately 337 answers from forest workers. Average factors are as follows: age 52.2 years, 22.5 years of experience, D. B. H. 18.8cm, pruning height 8.8m, tree height 15.4m, 1.4 persons/machine, 48.6 trees/day, 6 hours/day. Primary trees are SUGI and HINOKI. We inquired user's impression with a 5 point rating method, and tried to process the result using a fuzzy calculation method. The result was 3.16 points against a 5 points full mark. This means that the pruning machine <AB230R> is on a normal level. It was considered that the fuzzy calculation method is useful in processing this kind of survey.

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