Abstract
The aim of this paper was to provide an overview of the productivity of the stump lifting device Pallari KH-160, the distribution of working time, and to assess the dependence of the time and productivity of lifting operations on stump diameter in four different sample areas. Viru and Orguse sample areas were located in the Hepatica site type, Elva sample area in the Oxalis site type, and Rõuge test area in the Myrtillus site type. Viru sample area had smaller stumps compared to the others and had more stumps affected by decay. The highest productivity in terms of dry mass or volume was observed in stump lifting in Rõuge sample area, where 9.8 t of stumps were lifted per hour based on dry mass. The productivity of Viru and Orguse sample areas was lower, but these sample areas are located in the Hepatica site type, characterized by limestone substrates and leached soils. In contrast, Elva and Rõuge test areas are in the Oxalis and Myrtillus site types, respectively, with soils that are predominantly sandy. As the diameter of the stumps increased, the time required per stump increased, but the lifting speed per unit mass also increased. In other words, the productivity of lifting in stands with larger stumps is higher than in stands with smaller stumps. For example, the average productivity of lifting 10 cm diameter stumps is 0.8 t/h, for 20 cm stumps it is 2.2 t/h, and for 60 cm stumps it is 11.8 t/h.