Productivity and ghg balance of harvesting and forwarding in thinning of aspen hybrid plantations

The aim of the study is to evaluate the productivity and potential reduction of greenhouse gas (GHG) emissions due to use of the compact class Malwa harvester 560H and forwarder 560F in thinning of aspen hybrid plantations as well as to indicate the production cost and to analyse the possibility to use forest machines of this class in aspen plantations and to definite the quality of thinning, including the damage to the remaining trees, width of strip-roads, as well as to provide recommendations for the further development of the technology. These parameters have significant effect on productivity, fuel consumption and the vitality of the remaining trees. The productivity and cost are affected by tree dimensions, if the average harvested stem diameter is 12.2 cm, the productivity is 8.63 m per productive hour and the harvesting cost is 12.24 EUR·m, but in average productivity gives a big impact on the cost – 10.96 m per productive hour and harvesting cost – 10.04 EUR·m. The average forwarder load in the study is 4.03 m, forwarding productivity 5.1 m per productive hour and total harvesting and forwarding cost – 21.04 EUR·m. Harvesting related GHG emissions in aspen plantations are 4.12 kg CO2·m, including harvester related emissions – 49% and forwarding – 51%. According to the study results the harvesting GHG emissions using the Malwa harvester and forwarder are significantly smaller than of a middle-class forest machines due to smaller fuel consumption and high productivity values; besides, maintenance and investment costs of compact class machines are significantly smaller. The mechanical damage to roots and stems of the remaining trees during logging is inevitable. This is ensured by the use of recommended working methods setting special attention to the felling direction and the distance between the remaining trees in the stand, as well as avoiding unnecessary movements with the manipulator.