Water sorption in coated Scots pine (Pinus sylvestris L.) logs and influence of incipient decay

Abstract

Scots pine log specimens were given three different surface treatments and two different orientations of large cracks, and subjected to cyclic wetting and drying. Individual fitting of a mechanistic growth model was used to study the shape of absorption and accumulation curves and the final drying curve. Two parameters from this model (increase/decrease rate and maximum/minimum weight gain) were used for statistical analysis. The results indicate that wood tar results in less accumulated moisture over time than solvent-borne or water-borne coating or no treatment at all. An incipient attack by a white-rot fungus on parts of the material during storage affected water uptake greatly, often overriding surface treatment.

Keywords:

• Cyclic wetting
• incipient rot
• log building
• mechanistic growth model
• Scots pine
• water absorption
• white rot
• wood tar

Acknowledgements

The authors greatly acknowledge Bj⊘rn Slette (Norwegian University of Life Sciences) for building the experiment rig and contributing much of the work with weighing the test logs, Maria Nunez (Mycoteam as) for performing the microscope analysis and Professor Halvor Solheim for commenting on the manuscript. Guidance in finding a way to model results from cyclic wetting and drying over an extended period from Associate Professor Solve Sæb⊘ (Norwegian University of Life Sciences) is also greatly acknowledged, as is the funding granted by the Norwegian Research Council.