Analysis of deforestation before and after a logging ban was carried out in the forest area of Eastern Thailand by using GIS. The objective of analysis is to investigate the amount and location of deforestation area before and after the logging ban. The Royal Thai Government has banned all logging operations since 1989 which includes this area, for the reason that logging operations cause deforestation. In this study, six sets of forest and non-forest maps were transformed to vector GIS system, and overlaying techniques were applied. The investigation shows that, on the basis of forest area in 1973, the average annual deforestations were 5.6 % during 1973-1982, 1.8 % during 1982-1989 (before the logging ban), and 2.8 % during 1989-1991 (after the logging ban). The locations of deforestation were mainly on flat and low slope lands, not so far from roads. This indicates that the logging ban in 1989 has not decreased the rate of deforestation.

View full abstract

Slope failures of forest roads often occur and are disaters to forest lands. We studied the potential of cutting and banking slope failure of forest roads using the fuzzy theory. Evaluation systems of potential slope failure risks were based on the results of research taken in Totsukawa village, Nara prefecture. We learned that slope failures often occurred in the centers of concave curves, turning points of convex curves, wider portions of forest roads, steep slopes, and cutting areas of steep slopes. Discriminant ratios with the fuzzy theory were 68.9% for cutting slopes and 70.7% for banking slopes. Those with the quantification 2 method were 67.0% for cutting slopes and 72.1% for banking slopes. The advantages of the fuzzy theory are making evaluation systems easier according to different areas. This system could also be applied to other areas by adjusting the weight of importance and potential slope failure of each factor.

View full abstract

The purpose of this study is to determine if forest road disasters can be predicted by looking at the fundamental factors of geology, topography and forest road structure. This paper describes the results of analysis of these fundamental factors by the statistic quantification theory. The study utilizing the statistic quantification theory, involved analysis of 2 geological factors, 5 topographical factors and 6 forest road structural factors to determine their influence on factors of forest road disasters. The most influential factors on forest road disasters are the slope failure area in the watershed of the valley and the watershed area in topographical factors; structure of the banking side and the slope height of the banking side in road structural factors; and elastic wave velocity and schimidt hammer value in geological factors. The order of the main factors on forest road stability was determined 1) topographical factors, 2) road structural factors and 3) geological factors. The rate of correct discrimination by this analysis is 86.5%.

View full abstract

We conducted research on a working environment to construct a research plan for developing brush cutting machines. The factors we studied were steep slopes, soil hardness of forest floors, size of seedlings, obstructive characteristic of stumps, litter, fallen trees on the forest floor, and undergrowth. The results showed that brush cutting machine should have an attitude control mechanism and a semi walking capability. In addition, the machine should be able to move in a forest without damaging the seedlings that were planted in spaces of 150 cm by 60 cm. The stump height in a down slope were 40 cm or less, and the maximum diameter of the fallen trees were 40 cm. The machine should be able to travel over these stumps and fallen trees on the forest floor that have a trend to lay in a downward direction. Results from our sites investigation suggest that the machine should travel up and slopes to avoid damaging seedling and root systems.

View full abstract

We studied two algorithms of forest road planning using digital terrain map (D. T. M.). The first algorithm uses a road planning line on a constant gradient from the starting point. The second one uses a road planning line connecting two arbitrary points. The first method is same using compasses and terrain maps. Using this method, we were able to locate and exact road planning line on a constant gradient. The radius was 100m, the number of direction was 16, and a trial calculation times was 10. This second algorithm uses the following proceduces; The height of search point is an average of the starting point and the ending point. The position is searched in perpendicular bisector of both points. If the distance between the starting point and the search point and the search point is less than the search radius, then the search point is regard as the road passing point and new start point. If the value is larger than the search radius, then the search point regard as the temporary point. In this method, if the difference of altitude is larger, then the scatter of road gradient is greater. If the difference is smaller, the gradient is more uniform. At times, the search is incorrect because of geographical reason, or due to the value of control factors. By combining the former method, it is able to plan a road at the uniform gradient. There are some planned improvements for future, but this system is acceptable for present planning.

View full abstract

Actual speed of an articulated-frame wheel-skidder of full-tree skidding was investigated. Uphill speed with no load was affected by the grade, i. e.: the higher the grade, the lower the speed. The speed was about 6 km/hr when the gradient was 6°〜13°. The previous day's rain caused much slipping of tires at a section of 11°. The curves did not affect the speed because of the tractor's small turning radius. Even when the radius of curve R was 8m, the decrease of the speed against a straight course of the same gradient was only about 1km/hr. Downhill speed of straight courses with logs of less than 4.6m^3 varied over a range of 2.6〜14km/hr when the gradient was less than about -7°. When the gradient became -6°〜-13°, the speed was 4〜7 km/hr with a payload of 2.4〜4.6 m^3. The speed of lifting the small ends was lower than that of lifting the butt ends. Downhill speed with load was much affected by the radii of curves. For example, when the grade was about -11° and R was 30 m, the speed decreased to 3.5〜5.5 km/hr, whereas the speed on a straight slope was 4.5〜7.4 km/hr. When R=8m, the speed decreased to 2.2〜3.6 km/hr. Even when the gradient was only -5.5° and the R=20m, the speed of the skidder was affected negatively by the radius of curve. The above results can be used to design a skid road for full-tree skidding.

View full abstract

A simulation program for the operation system cooperated with a mobile tower yarder, a log-making processor and a skidder was developed with the use of simulation language: GPSS. The purpose of the simulation program is to examine the best combination and the relative location of these machines from the viewpoint of log productivity. It was proved that this program was able to simulate adequately the condition and the flows of the operation system, judging from the comparison of the simulation results with the actual results of a study case. Then, the best condition of the system in the study case was examined throughly, as an example of its application. The results of the simulation indicated that the system using both the mobile tower yarder (K303) and the skidder (Bell super logger) would work most efficiently, when the log-making processor in which productive capacity was duplicated, was used, and when the processor on the forest road was placed within the distance of 150 m from the mobile tower yarder.

View full abstract

In this report, a locus control system for a Knuckle Boom Crane is developed using the 3 dimensional Joy Stick as an input device. The Knuckle Boom Crane has 4 degrees of freedom, because of the Telescopic Cylinder; thus a restricted condition is needed for the locus control. In this control system, the length of the Telescopic Cylinder is in proportion to the distance from the base to the tip of the Knuckle Boom Crane. The system allows an operator to manage the Knuckle Boom Crane with only one Joy Stick instead of manipulating the several levers. As a result of the experimentation, this controller is able to keep the tip of the Crane within 20 mm from a target line. This accuracy is enough for forestry use. Because the amount of the hydraulic fluid is limited, this controller was a function to keep the velocity of movement less than the velocity of maximum flow. So this control system is not limited by the rack of hydraulic fluid, and makes the velocity larger.

View full abstract