THE EFFECTS OF HIGH-TEMPERATURE HEAT-TREATMENT ON PHYSICAL PROPERTIES AND SURFACE ROUGHNESS OF ROWAN (SORBUSAUCUPARIA L.) WOOD

摘要

Heat treatment of wood has attracted a lot of attention both in Europe and recently in North America as an environmentally-friendly wood-protection method. The untreated wood is hydrophilic (high affinity for water). During the heat treatment, wood becomes more and more hydrophobic (low affinity for water) with increasing heat treatment temperature. As a result, it becomes dimensionally more stable compared to untreated wood. The high temperature thermal treatment of wood is an environment-friendlymethod for wood preservation. This technique has attracted considerable attention in recent years. This study investigated the influence of heat treatment on the physical and surface roughness of Rowan {Sorbus aucuparia L.) wood to understand its role inwood processing. Samples obtained from Kastamonu Forest Enterprises, Turkey, were subjected to heat treatment at varying temperatures and durations. The physical properties of heat-treated and control samples were tested, and oven-dry density, air-dry density, and swelling properties were determined. A stylus method was employed to evaluate the surface characteristics of the samples. Roughness measurements, using the stylus method, were made in the direction perpendicular to the fiber. Four main roughness parameters, mean arithmetic deviation of profile (Ra), mean peak-to-valley height (Rz), root mean square roughness (Rq), and maximum roughness (Ry) obtained from the surface of wood were used to evaluate the effect of heat treatment on the surface characteristics of the specimens. Significant difference was determined (p = 0.05) between physical properties and surface roughness parameters (Ra, Rz, Ry, Rq) for three temperatures and three durations of heat treatment. The results showed that the values of density, swelling and surface roughness decreased with increasing temperature treatment and treatment times. The results obtained in this study provide important information for future research and utilization of thermally modified wood.