PEER-REVIEWED ARTICLE bioresources.com Bal (2013). “Heat treatment of C. libani,” BioResources 8(1), 211-219. 211 Effects of Heat Treatment on the Physical Properties of Heartwood and Sapwood of Cedrus libani Bekir Cihad Bal Effects of heat treatment on the physical properties of heartwood and sapwood of Cedrus libani A. Richard, such as density, equilibrium moisture content, swelling, and fiber saturation point were investigated. Heartwood and sapwood samples were treated at 140, 160, 180, 200, and 220°C for 3 h. After heat treatment, the physical properties of the samples of wood were determined according to Turkish standards. The results showed that mass loss increased and physical properties decreased as the treatment temperature increased. As the treatment temperature was increased, the mass of the heartwood decreased more than that of the sapwood, which may be due to the fact that the heartwood had greater extractives content. Conversely, even though the mass of the heartwood decreased more than the mass of the sapwood at the treatment temperature of 220°C, its physical properties, such as equilibrium moisture content, swelling, and fiber saturation point, decreased less than those of the sapwood. Keywords: Cedrus libani; Heat treatment; Heartwood; Sapwood; Physical properties Contact information: Department of Forest Industry Engineering, Faculty of Forestry, KSU, 46060, Kahramanmaraş/Turkey, e-mail: bcbal@hotmail.com INTRODUCTION Wood has been an important raw material for many centuries, and it has been evaluated for use in numerous different applications. However, it has some undesirable properties that restrict its use for some applications, and work has been conducted in an effort to develop methods for improving these undesirable properties. Hill (2011) noted that these methods include chemical, thermal, and impregnation modifications, each of which has some advantages and disadvantages. Heat treatment is regarded as a more environmentally-friendly method than others that use chemical substances (Kocaefe et al. 2008; Gunduz et al. 2010; Garcia et al. 2012). The heat treatment of wood results in physical and chemical changes, including increased lignin content, increased dimensional stability, improved durability, decreased mechanical properties, lower equilibrium moisture content, and darker color (Esteves and Pereira 2009). The results that are achieved with heat treatment are affected by several factors associated with the wood, such as its density and its species, as well as the temperature and duration of heat treatment. In addition, the thermal conductivity of the wood influences the results of the heat treatment. Several factors can affect the thermal conductivity of wood. As Simpson and Tenwolde (1999) stated, “the thermal conductivity of wood is affected by a number of basic factors: density, moisture content, extractive content, grain direction, structural irregularities such as checks and knots, fibril angle, and temperature.”