The Effect of Heat Treatment on Compression Strength of Silver fir (Abies alba Mill.) and Ash Wood (Fraxinus angustifolia Vahl.). Short notes
This study investigates the effects of thermal modification on the compressive strength parallel to the grain of ash (Fraxinus angustifoglia Vahl.) and fir (Abies alba Mill.) wood. Specimens were thermally treated at 130°C, 180°C, and 220°C for durations of 2 and 8 h under atmospheric conditions. Mass loss increased with both temperature and time, with fir exhibiting greater loss than ash, up to 20.3% and 15.7%, respectively, at 220°C for 8 h. Compressive strength was influenced significantly by treatment intensity. Fir showed minor improvements at lower temperatures but experienced a reduction of up to 23.0% at the highest treatment. In contrast, ash displayed enhanced strength at 180°C (up to +15.1 %) and retained better mechanical performance at 220°C, with a maximum reduction of 11.3%. These findings demonstrate that heat treatment can both enhance and deteriorate compressive strength depending on the treatment severity, emphasizing the need to optimize thermal parameters for maintaining structural performance in wood applications.