Determining the effect of the number of log sorts on mechanised log processing productivity

New Zealand researchers set out to determine the optimal number of log assortments.

As with many countries, New Zealand forestry must supply logs from one stand to many different markets. These markets include import and export customers. It is not unusual for a harvesting operation to produce between 8 and 22 log sorts from one tree species (Pinus radiata). Also, because New Zealand’s log exports have being growing strongly over the last few years, the prices for major export log grades have increased and converged with structural sawlog grades. Because of this price convergence, the incremental value gains from producing a wide range of log sorts have reduced. The researchers carried out production studies at two harvesting operations, where the mechanized processing was studied in different market scenarios (5, 9, 12, and 15 log sorts). Both product value and the operational impacts on log processing productivity where studied. The results showed that 15 log sorts decreased processor productivity by approximately 10%.  Nine log sorts were estimated to be the optimum number when considering the value produced per productive machine hour.

The research was titled “The effect of the number of log sorts on mechanized log processing productivity and value recovery”, and was published in the International Journal of Forest Engineering, Vol. 26(1) 2015. The authors were A Tolana and R Visser. Source:

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