The Rankine assumptions were used as a basis for developing equations for calculating active and passive earth pressures within a slope extending to infinity. The analysis considers: cohesive and noncohesive soils, the angle of internal friction of the soil, seepage forces caused by a ground water table that is parallel to the ground surface, and the plane on which the stresses are to be found may be at any inclination.

General solutions for the failure surfaces in slopes where the assumptions of the infinite slope theory are valid have been derived. The solutions are applicable to layered systems and to any seepage conditions provided that both layering and ground water flow are parallel to ground slope. It is concluded that the infinite slope theory is of limited appUcability unless modified. A modification to enable transition from the active to passive stress states is suggested.

Lodgepole pine (Pinus contorta Dougl.) in Wyoming was logged to near complete standards using a feller-buncher, grapple and choker rubber-tired skidders, and a portable chipper. Cost of removing the commercial timber was comparable to costs incurred in conventional harvesting. Cost of removing the logging residue and chipping it on the site shows promise for future utilization. A more efficient logging system is simulated and proposed for reducing the costs of near complete harvesting in the future.

He has been involved with logging, forest roads, and erosion on various research assignments since 1969. JAMES CASS received a bachelor's degree in psychology in 1973 and an M.S. in mathematics (statistics option) in 1975, both from Montana State University. While doing graduate work at Montana State, he did the statistical analysis for this study. He is presently employed as a statistician with the Montana Department of Revenue in Helena, Montana.

Experience has shown that road networks needed for conventional logging can lead to severe erosion in the Idaho Batholith, In an attempt to develop an environmentally acceptable logging system, in 1971 the Forest Service, USDA, in cooperation with Boise Cascade Corporation, began an experiment with balloon logging in Anderson Creek near Garden Valley, Idaho, on the Boise National Forest. The balloon logging system resulted in far less envirohmental impact on the land as compared to conventional logging methods. This conclusion is based on observations both shortly after the area was logged and after several years had passed. This sale proved the physical capabilities of logging with the balloon system in the Idaho Batholith area; however, the conditions are not ideal, with the steep, broken terrain and low timber volumes. A description of the equipment, the methods of operation, and problems with the system are included in the report. An economic analysis of the logging is presented in the form of regression equations. Factors within the analysis include thousand board feet logged per acre, board feet per piece, pieces per productive hour, turns per productive hour, percent productive hours, and costs per thousand board feet.