In the last decade, technological innovation in the forest operations sector has allowed levels of mechanization alternative to agricultural tractors and animal logging. These machines are used to load logs from skid roads and move logs to the next pile, until the load space is fully loaded. Fortunately, in recent years the development of new technological progresses in forestry mechanization created an alternative operation on ground-based system with the use of a combi-forwarder for wood forwarding. These innovative machines have the advantage that only one machine can perform logs bunching and primary transport. Infact, pull stems by the winch from the stump to the road, after they have been cross-cutted by chainsaws, it loads by the forwarder’s crane the logs and transports them to the landing, where they are unloaded with the crane in piles.

The aim of the present study was to analyse the operational time consumption, to estimate the productivity of the combi–forwarder with a built-in single-drum winch in beech stands evaluating the forwarding and winching distances, log’s volume transported per turn by the machine, as well as the extracting costs. The study was conducted in low-intensity shelterwood cuttings in beech forest, located in Western Balkan Mountains, Bulgaria.

The mean productivity of the combi–forwarder was 7.09 m³ PMH^− 1 and 6.11 m³ SMH^− 1 close to that of the cable skidders and forwarders in similar conditions. The net costs for the studied combi–forwarder were calculated of 25.33 € per productive machine hour and 4.13 € per m³. The variable costs (70%) have a leading role, followed by labour costs (22%) and fixed costs (8%). The use of a combi-forwarders facilitates chainsaw operators, as some of the operations are carried out at the roadside in better working conditions: flat terrain and support of the crosscutting phase. The results from the study are useful to introduce and to integrate the combi–forwarders with shelterwood systems and to achieve economic and environmental efficiency of timber harvesting in deciduous forests.

在过去的十年中，森林经营部门的技术创新已经实现了农用拖拉机和动物伐木的机械化替代。这些机器用于从滑道装载原木并将原木移动到下一堆，直到装载空间满载。幸运的是，近年来林业机械化新技术进步的发展创造了一种替代地面系统操作的方法，即使用组合式集运机进行木材运输。这些创新机器的优点是只需一台机器即可执行原木捆扎和初级运输。事实上，通过绞车将树干从树桩拉到道路上，在被链锯横切后，由货运代理的起重机将原木装载并运输到平台，在那里用起重机将它们成堆地卸载。

本研究的目的是分析操作时间消耗，估计山毛榉支架上带有内置单鼓绞车的组合转运机的生产率，评估转运和绞车距离、机器每转运输的原木体积，以及提取成本。这项研究是在保加利亚西巴尔干山脉山毛榉林的低强度防护林插条中进行的。

组合集材机的平均生产率为 7.09 m ³ PMH ^{- 1}和 6.11 m ³ SMH ^{- 1}，接近类似条件下的电缆集材机和集材机的平均生产率。经计算，所研究的组合式集运机的净​​成本为每生产机器小时 25.33 欧元和每 m ³ 4.13 欧元。可变成本（70%）占据主导地位，其次是劳动力成本（22%）和固定成本（8%）。组合式输送机的使用为链锯操作员提供了便利，因为一些操作是在路边进行的，工作条件更好：平坦的地形和横切阶段的支持。研究结果有助于引入组合集运机并将其与防护林系统集成，并实现落叶林木材采伐的经济和环境效率。