Challenges and constraints of harvesting in mountain forests

Harvesting has been an important forestry activity over the years and has been an essential operation in the mountainous forest areas of Austria. This operation helps generate revenue for forest owners by selling harvested timber and logs and managing forest ecosystems by opening gaps for regenerative processes. However, extracting trees from mountainous areas is sometimes difficult and susceptible to multiple constraints, making it more complicated and costly than harvesting operations in other forest types. Therefore, trees and forests in mountainous areas provide a wide range of resources and services, particularly timber production. Hence, this position paper discusses some key issues and limitations associated with harvesting in difficult or steep environments.

Several factors influence the selection of harvesting techniques and machine types. One crucial factor is terrain, which encompasses the elevation and slope of the area. This factor is particularly important in countries with vast forested mountain regions, like Austria. Therefore, it is essential to understand the available harvesting equipment and techniques and the constraints associated with these operations. Furthermore, this understanding serves to overcome these challenges, leading to improved economic efficiency and work safety. The photo on the right demonstrates a typical skidding track constructed during harvesting operations in the forest.   

In Austria, various methods are commonly used for timber extraction, including harvesters, forwarders (sometimes supported by a winch), and cable yarding. Cable logging systems are highly effective in extracting timber from challenging and steep terrain areas. However, they are also quite expensive, and there is potential for increased availability of contracts. Currently, only one-third of the harvests in Austria use cable yarding systems. An alternative method practiced in Austria involves using harvesters and forwarders with a winch-assisted system. This approach is cheaper than cable yarding and helicopter harvesting systems. However, it has limitations, such as the cost of equipment purchase, construction of skidding trails, soil disturbance, road maintenance, and depreciation of soil fertility and conditions.      

The utilization of land-based machinery for harvesting operations necessitates the presence of a well-established road network that extends into forests. Additionally, forests in difficult, steep, or unstable terrains and those situated away from roadsides or other infrastructure are often safeguarded against natural disasters such as rock falls and avalanches. For instance, robust spring steel nets are frequently installed at forest boundaries, with construction based on slope steepness and rock fragment size. However, while this protective measure safeguards the infrastructure downstream, it incurs additional installation and maintenance costs. Moreover, the implementation of such protection measures typically depends on the existence of an adequate access road to the forest. Therefore, the significance of forest roads should be emphasized.

Different harvesting options exist in difficult terrains without appropriate forest road access, each with its obstacles. Having well-connected road networks dramatically reduces harvesting costs. For example, most importantly, in Austria, when access roads are available, the cost might drop by half (50%) from €70/m3 without access roads to €35/m3 with access roads. However, constructing roads for harvesting is difficult because of unpredictable circumstances, which are influenced by factors such as material costs, soil types, soil conditions, and topography (i.e., terrain and slopes). Consequently, harvesting on steep slopes and rocky terrain using chainsaws with manual harvesting techniques is cost-effective but sometimes laborious, which comes with the challenge of navigating mountainous areas and the risk of accidents.

Furthermore, transporting harvested logs from mountain forests to sawmills is complicated and expensive, particularly in locations with limited road access. Therefore, temporary roads are required, and geography, slopes, seasons, and soil conditions determine the construction costs. Despite these challenges, it is crucial to acknowledge the potential benefits of employing the advanced equipment mentioned previously. Using sophisticated equipment and machines will not only enhance work efficiency but also reduce environmental impacts, improve safety, enhance accessibility, and increase cost-effectiveness. However, it is essential to consider the cost of purchasing such equipment before assessing its overall benefits.

To conclude, harvesting in mountain forests poses various obstacles and constraints for forest management and conservation. Nevertheless, it is advised that effective operations planning, using smart harvesting equipment and techniques, and cooperation with other stakeholders can limit the challenges and constraints mentioned above in this position paper. So, these suggestions will help in setting an appropriate balance between difficulties and opportunities to ensure sustainable harvesting operations in the mountainous areas of Austria.