The first part contains a historical reference on the participation of domestic scientists, mechanics and designers in the creation of cars, tractors and mechanization tools. The main methods of organization of science in the country, university, at the department . are considered. Presented: logical model of the studied object, methods of scientific penetration, including methods of theoretical and experimental research, methods of measurement and measuring systems, quality of research and development . The second part is devoted to modeling of work processes and maintenance of forest machines. The basic principles of calculation and calculation schemes equivalent to a dynamic system. are considered. A large volume of mathematical models of the dynamics of forest machines and the system "forest machine - the subject of work" and the results of their research, as well as some indicators of production and technical operation of forest machines. Designed for students of forestry and forestry engineering faculties, graduate students, researchers, engineers of the logging industry and forestry . ; Grif: Recommended by the Forestry Education Educational and Methodological Association as a textbook for students of higher education institutions , students in the direction of 250400 - "Technology of logging and wood processing industries" and 190600 - "Operation of land transport and transport equipment"