Current issue: 55(3)
Under compilation: 55(4)
Forest transport of timber in Finland has been arranged as horse haulage during winter time using horses vacant from farm work. Tractors have now begun to replace horses in agriculture, which will lead to shortage of horses for timber harvesting in future. The aim of this investigation was to find a method of mechanized forest transport suitable for Finnish conditions. The method should be provided by an agricultural wheel tractor that is shared with agriculture. It should also be applicable to timber transport of relatively small forest holdings.
A method for time studies of tractor driven timber harvesting was developed. The competitivity of tractor transport of timber against the traditional method was studied in four pulpwood harvesting sites. The results suggest that if the tractor forest transport method in question is to be applied in practice, conditions should first be chosen which favour it most. A tractor forest transport method evolved on the basis of experiments presupposes certain conditions to be successful. These include snow for the construction of the packed-snow driveway, frost to harden the driveway, the location of strip roads in relatively easy topography, and of the main haulage road that is gently sloping in the haulage-loaded direction. The optimal transport distance for this method are about 3-10 km.
The PDF includes a summary in English.
According to the available literature, the times when pulpwood limbing was made by axe and barking by hand tools, barking either had no effect on the pile density (if limbing quality was good) or increased pile density (if limbing was bad). When rotary barking machines are used, the branch stumps remain intact during barking. Therefore, if there are branch stumps in the pulpwood, barking decreases the pile density. Nowadays, when power saw limbing is a common practice in Finland, barking presumably greatly decreases the pile density, due to the fact that in power saw limbing branch stumps are numerous and high. Therefore, the method to estimate the solid volume of a pile of unbarked pulpwood are not applicable to barked pulpwood without modification.
The PDF includes a summary in English.
In 1957 the annual cuttings in Finland were 40.2 million m3 without bark. The aim of the study was to estimate the rate of mechanization of harvesting of timber in Finland, and make a prediction of the state of mechanization by 1972. According to the study, harvesting and transportation of the felling volume in 1957 would have required about 25.5 million working hours. Mechanization of forest work has decreased it only by 0.32 million working hours. The profitability of forest work has improved in 1950s, which is mainly due to changes in harvesting, such as shifting to longer lengths of pulpwood and props and cutting unbarked timber.
The study predicts that in 1972 it will take 14.8 million working hours to harvest and 5.4 million working hours to transport a corresponding felling volume as in 1957. However, a new way of producing timber or a working method of wood may change the picture completely. Reduction in harvesting expenses through mechanization may lead to diminishing the minimum diameter of logs, which affects profitability of work. It is also probable that mechanization of wood transportation will lead to working sites with longer distances of forest transportation. Also, industry using wood as raw material will also obviously expand.
The article includes a summary in English.
The aim of the study was to compare the newly introduced brush cutter to ordinary hand tools in clearing of cutting areas and thinning young birch (Betula sp.) and Scots pine (Pinus Sylvestris L.) stands. Working with a prototype of the brush cutter, Brushmaster, reduced the total working time by 15-20% compared to bush knife and axe, in spite of the cutter’s weight. At rainy weather the advantage of Brushmaster dissapeared because of clogging of the cutter’s air filter. The prototype proved to be more effective when clearing a cutting area, and hand tools seemed to be faster if damage to the remaining trees have to be avoided.
In addition, eight either lighter or more effective motor saws or brush cutters were compared mutually, and the effect of motor effect, weight, handiness, arrangement of suspenders and handles is discussed. With these improved types of the cutter it was possible to shorten the total working time in thinning of stands (mostly clearing of young stands) to 30-40% of the total working time compared to hand tools. The most modern saws appeared to be best adapted in clearing cutting areas.
The article includes an abstract in English.
When ditches are dug in forest drainage, smaller stones are removed by hand, but the larger ones require the use of explosives or stone lifting machinery. Use of explosives have been a more common method for the larger stones. Due to development of detonation methods, it has also been used for smaller stones than earlier.
The investigation was a time study comparing five different stone lifting machines. Time needed for different stages of the work was measured. The stages lasted approximately as long for all of the machines. However, the effectivity of the machines could not be determined, because the stones removed were not similar enough. Stone lifting machine Pekka appeared slightly more effective than the other four machines. It was also easy to assemble, disassemble and move.
The article includes a summary in German.