On the basis of various extraction models, the utilisation of equipment by forest owners performing work in their own forests was calculated. The utilisation of machinery is dependant principally on the size of forest estate, that is, the quantity of work. On the basis of the utilisation of equipment and work costs, the cost of felling and extraction for different sizes of forest estate are provided. Comparing the price of lumber on the trunk road and the cost of extracting the wood, the economic efficiency of work is derived and is given as the coefficient of economy. On small forest estates and stands in early development, the use of machines in extracting lumber is not economical. The smaller the extent of work, the lower the coefficient of economy; the simply fitted farm tractor is sufficient and cheaper for small estates. Large tractors should be considered for working in tough conditions and where there is sufficient work. The economic efficiency of work is decisive in selecting equipment for work in the forest.