Harvesting process

Abstract

The harvesting process consists in the mission to get the tree from the forest site to a wood processing mill. Forest harvesting refers to cutting and delivering trees in a productive, safe, economic, and ecological process. It includes the conversion of trees into merchantable raw material according to specific industrial or individual requirements and needs. In general, the wood passes through several processing steps before it can be transported. The most important operations are felling, delimbing, debarking, bucking, chipping, wood extraction, piling, loading, and wood transport. Depending on the qualitative demand, environmental and social restrictions, technological know-how, and access to technologies, some of the steps might be skipped. Also, the sequence of the processing may vary, going that far that the full tree is transported and processed at a central log yard. In the tropics, a variety of forest ecosystems can be found. From dry savanna to evergreen tropical rainforests, big differences exist in biodiversity, wood volume produced per area, soils, and climate. No matter what forest ecosystem is intended to be managed, they are all very sensitive and may be easily degraded or destroyed. On the other hand, there are many tropical regions with climatic conditions favorable to tree growth. It has to be differentiated between native tropical forests, generally managed in form of exploitation, and intensively managed forest plantations. While selective logging in native forests has to be done extremely careful considering many restrictions concerning mechanization of the harvesting process, in forest plantation in general, high volumes are produced in short rotations and harvested in fully mechanized clearcuts, because soil disturbance can be corrected before new planting. Forest harvesting has the highest ecologic and economic impact of all forest operations. It has to be thoroughly planned and executed to avoid damages on the ecosystem and putting at risk sustainability issues of the forest-wood chain. Planning of harvesting occurs in several planning levels, starting from a macroscale considering the general issues like volumes and areas, forest access, or transport up to an individual microscale planning on the single stand. The base of all planning is detailed inventories, consisting of quantitative and qualitative data of natural resources, road systems, technologies available, and logistic capacity of the company or forest owner. With these databases and a geographical information system, powerful planning tools might be developed for optimizing harvesting and transport operations. One of the most important steps concerning harvesting is cost planning of machine and labor cost. In general, wood harvesting is a very labor- and machine-intensive activity. Depending on the wood utilization, in this planning step, the cost calculation often shows that the harvesting operation is too expensive and can’t be conducted in an economic feasible way. At least, the forest road system or other transport means have to be carefully evaluated and planned, too. Transport distance and infrastructure are key issues in harvesting planning. This chapter aims to give an overview about the important issues to consider for the harvest process and highlights how complex the overall harvesting operations are.