An economic comparison of two Swedish first thinning systems in a Scots pine stand (Pinus Sylvestris L.)

Abstract

The results of an economic comparison of two Swedish thinning systems in the first thinning of a Scots pine (Pinus sylvestris L.) stand is presented. The operation was performed in a 36 year-old stand located 30 km north of Stockholm, Sweden. The conventional thinning system used in Sweden today is associated with a high density of forest trails and difficult physiological working conditions for the cutter. This system was compared with a system designed to improve the biological situation in the stand after the thinning by increasing the distance between forwarding trails and to improve the physiological working conditions for the cutter performing the cutting function by using a thinning roller. The study was to determine if this modified thinning system would be an economically viable alternative to the conventional system. Differences in cost components was also to be determined through a detailed analysis of the working methods used for each system. A time study was carried out for each function in both systems to find the composition of productive work and the productive performance rate in each function. This rate was related to unit costs (industry averages) to find the total cost for each function. The cost of the biological implications of the introduction of clearcut forwarding trails into the stand in each system was found by relating the expected loss in volume and quality to the present value of the wood. The total cost of each system was calculated for three levels of small-scale operations and one company operation. This total cost was found to be between 19-35 SK/m3 (Swedish-kronor-per-cubic-metre-cut) lower for the conventional system. This was mostly due to the extra cost induced by the winching function and, to a much lesser extent, a lower performance rate for the cutting function in the modified system. The difference from these factors, however, was offset by 7 SK/m3 in lower biological costs and about 10 SK/m3 in a lower cost in the forwarding function for this system. Thus, the modified system was found not to be cost-competitive with the conventional system. It has been recommended that a similar study to the one presented in this report be conducted on a system which employs the thinning roIler, extends the traiI spacing used in the conventional system (to 30 m or more), but does not use a winch.