COMPARISON OF COSTS IN PRE-COMMERCIAL THINNING USING MEDIUM-SIZED AND SMALL-SIZED HARVESTERS
The aim of this study is to compare productivity and costs of medium-sized and small-sized harvesters in pre-commercial thinning. In this study the data on harvesting productivity were obtained in stands, where biofuel was prepared using two medium-sized and two small-sized harvesters equipped with different harvester heads. In total 677 m3 of wood was prepared with medium-sized harvester, but with small-sized harvesters 1 164 m3 of wood was prepared. Although the total annual costs of small-class harvesters are lower by 16 %, comparing with middle-class harvesters, the productivity rates shown by the middle-class harvester John Deere 1070 E (equipped with H 754 harvester head) are significantly higher and the average wood preparation costs are lower, comparing with the other harvesters employed.