Possibilities to develop machinery for logging operations on sensitive forest sites

This paper includes some basic knowledge to be considered when discussing about the quality of work in harvesting wood and how to monitor it. This knowledge may aid to form an appropriate view on mechanised logging, environmental issues and trade of forest products. Many forest owners feel today, that leaving a good quality of work behind is the most important requirement set for logging machinery in the future. It is possible to present to the forest machine and equipment manufacturers some ideas on how to promote and influence the development of logging machines and equipment. This paper is partly based on a literature study, partly on theme interviews. Recent literature on productivity, machine and method studies on logging was examined from the quality of work point of view. Observations supporting an improvement in the quality of work were recorded. The idea was not to find out the level of the quality of work in practice as such, but to assess the relationships between the methods, machines and equipment used in respect to the quality of work. The interviews were conducted from May 22, 2000 to October 2, 2000 in Finland. The data consisted of six persons responsible for logging in a wood procurement district, six representatives of forest machine manufacturers and five logging contractors. A good quality of work in logging is characterised by doing it in an agreed way. Indicators for reaching the goals are evaluated by assessing the damages caused to the remaining trees, the rut formation, the strip road spacing and width, the way the thinning regimes are followed and the choice of trees to be cut. The target level is formed as a joint effect e.g. of efficiency in wood production, of credibility of mechanised operations, of considering the environment and of fluency in trade of forest products. Contributing factors to reach a good quality of work are the organisation of the logging, the forest machine operator as well as the machine and equipment technique. These factors may get a weighting value. However, the final result is a product of these factors, and all of them have to be considered. When looking at the situation today the human influence in logging, especially the role of the operator, is getting more emphasis. On the other hand, in the long run the possibilities to develop appropriate technologies are dominating, especially the use of new technologies. From the point of view of logging machinery the main factors affecting the work results, are the mobility of the vehicle, how to operate it and the work environment. In this paper, based on the development needs and possibilities, those aspects are looked at. An assessment of the present state is given and presents a basis for a more precise prediction of realistic targets. Based on a literature review and interviews conducted, it is possible to conclude, that there still is great potential to improve the quality of work in logging. Some direct technical improvements could promote the quality of work, but there are even some other actions, which indirectly through the operator would have a positive effect. An improved quality of work is often also improving the productivity in work. Furthermore it makes the organising of the logging operations easier and makes it possible to operate in a more demanding work environment even year around and 24 hours a day. The following is a list of research and development (R&D) needs concerning forest machinery, where inputs would be justified: • Better visibility (illumination, no dazzling, visibility) • Analysis of the CTI-system and eventual construction and testing of a test machine • The properties of tyres (width, diameter, tread, pressure) and their development • Control of the crane and its development (e.g. the automatic functions) • The role of a rotating cab on the operator, his productivity and the work result • Research into the role of levelling (seat, cabin, whole machine) • Steering of the machine (turning radius, “cutting” of corners) and possibilities to develop a vehicle with frame-steering and turning wheels • Research into the possibilities to utilise on-board weighing scales • Lighter machine construction • The role of tracks and comparison of different tracks • The role of a balanced boggie and its comparison with a single wheel • The role of the size of the harvester head on the operation control, work result and productivity • Possibilities to increase automation • Possibilities of work rotation and its effect on a normal logging system • The effect of a harwarder (harvester-forwarder) on the operator’s wor

Production analysis of an excavator-based harvester : a case study in Finnish forest operations.

A production study was conducted for an excavator attached with a harvesting head under two stand conditions in northern Finland to determine and examine hourly productivity, unit cost, and working pattern. Before clearcutting, stand 1 was a natural stand composed of birch and spruce. Stand 2 was a pine plantation that was to be thinned a second time. Felled trees had an average diameter at breast height (DBH) of 17.8 and 15.8 cm, 7.64 m and 10.69 m in total merchantable height, and volume per tree of 0.18 and 0.20 m3, in stands 1 and 2, respectively. The results indicated that the productivity of this machine in forest operations was at the same level as that of Nordic purpose-built harvesters. Hourly productivity averaged 12.24 m3 per productive machine hour (PMH) in stand 1 and 10.43 m3/PMH in stand 2 and was affected primarily by DB H and the number of cuts or logs from a tree. Hourly costs were estimated at FIM 466.21/PMH ($84.8/PMH), which provided a cost estimate of FIM 69.47/m3 ($12.6/m3) in harvesting stand 1 and FIM 74.35/m3 ($13.5/m3) in harvesting stand 2. Working pattern of the excavator was also examined. The average boom reach was between 6 m and 7 m and the maximum vertical revolving angle was about 130 to 140 degrees. Moving distance between harvested stops averaged 16.11 m and the cutting width of a strip ranged from 8.0 to 10.0 m