The productivity of a pulp and paper mill is dependent on the quality of wood chips entering the mill. Most kraft mills operate with a “bottleneck” and this is typically the recovery boiler. For these mills, using chips with “x%” higher pulp yield can result in a “3x%” increase in output of paper. This can represent a substantial increase in productivity and potential profit for the mill.
In the case of plantation Eucalyptus wood, the quality of the chips from harvested trees is dependent on many factors, such as the climate and seed quality. but it is also dependent on the age of the trees at harvest. In most cases, allowing trees to grow for a longer time before harvest will cause the pulp yield to increase. These older trees would, therefore, be of great interest to pulp and paper mills. Unfortunately, the plantation owner may be reluctant to supply older trees as delaying harvesting will cost money.
This paper will examine the conflict of interest between the pulp mill operator and the plantation owner. A mathematical model has been constructed which enables calculation of the impact to be calculated of varying the age at harvest on the overall economics for the whole fibre chain, “from seed to paper”. Input data used in the model was sourced from Eucalyptus plantations in Tasmania that are supplying Japanese integrated fine paper mills.
It is proposed that, if a pulp and paper mill is going to use plantation chips, the management at the mill should take an active interest in the management principles used by the tree grower.