211 WOOD RESEARCH 60 (2): 2015 211-218 INFLUENCE OF DENSIFICATION ON BENDING STRENGTH OF BEECH WOOD Miroslav Gašparík, Milan Gaff Czech University of Life Sciences, Faculty of Forestry and Wood Sciences Department of Wood Processing Prague, Czech Republic (Received February 2014) ABSTRACT This paper reports the influence of densification and cyclic loading on bending strength of beech (Fagus sylvatica L.). There are many studies dealing with the bending strength of native wood but densified wood is much less explored. Beech wood was loaded by three different numbers of cycles (1 000, 2 000, and 3 000 cycles). Bending strength values of cyclically loaded densified wood were compared with cyclically non-loaded wood. The densified wood had, in average, bending strength values higher by 5.7 % than the non-densified wood. However, the number of cycles did not influence the bending strength unambiguously and essentially. KEYWORDS: Bending strength, beech, densification, cyclic loading. INTRODUCTION Wood is a material with properties that make it ideal for various uses. On the other hand, in the wood industry there are efforts to improve certain properties of wood to match those of other materials. Basic processes to change the properties of wood use only the force application, or factors, such as heat and humidity. Densification is ranking among such processes. Wood densification is a process that achieves an increase of wood mass per volume unit (the density increases) by the means of a pressing force, or eventually by other factors, such as changes in temperature and moisture, or additions of chemical agents (Chuchrjanskij 1949). Various methods of densification are known, such as uniaxial, biaxial, peripheral, and 3-D pressing, as well as wood rolling. During wood rolling, the strength required to densify the wood is supplied from a couple of rollers, which the wood passes in between (Fig. 1), where h is the material’s original thickness and h 1 is its thickness after the densification.