Heartwood and Extractive Content of Scots Pine in Southern Finland: Models to Apply at Harvest


  • Jori Uusitalo


Cambium age, heartwood, radial growth rate


The biggest obstacle to better utilization of Scots pine heartwood lumber is the difficulty of separating heartwood in the sawing process. The aim of this study was to analyze the variation in heartwood proportion and extractive content of Scots pine in southern Finland, and to develop a model that could be employed at harvest to predict heartwood taper. In accordance with many previous investigations, the number of rings in heartwood at any tree height is under the control of time and is thus best predicted by cambium age. The results suggest that the heartwood starts to form when the cambium age is roughly 20 years and increases by two-thirds of a year ring annually after it has been initiated. In order to apply this model in practice, we need accurate estimates of the cambium age and the radial growth rate as well. A comprehensive model is presented that enables prediction of heartwood taper for mature Scots pines while handling the tree at harvest if the tree age is known. The results suggest a mean error of roughly 2 cm in predicting the heartwood diameter by using the equations developed.


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