Turkey possesses all types of parent materials or bedrocks like metamorphic, sedimentary and volcanic belonging to different geological era and periods. Some parent materials contain evaporitic sediments with salt, gypsum and high contents of alkaline materials which mostly prevent the growth of climax vegetation. The country has a rugged and high topography, related to tectonic movements, and volcanic activities which mainly occurred in Tertiary and Quaternary eras. The mountains are divided into three groups in terms of formation and ecological importance namely; orogenic mountains, volcanic mountains and uplifted blocks or horst mountains. The ecological importance of the topography is fully stressed by altitude, aspect and climate. The forests in Turkey can be classified on the basis of ecological features as: humid-mild deciduous, humid-cold coniferous on the north facing slopes of coastal belt of Northern Anatolian Mountains; subhumid-cold continental coniferous in the north facing slopes of backward part of Northern Anatolian Mountains; subhumid-semiarid semi continental coniferous on the plateau and mountains of southern basins of northern Anatolian Mountains; semiarid continental timer Anatolia Quercus spp. - Juniper spp. - Pinus nigra, semiarid-subhumid Quercus spp., Mediterranean Pinus brutia and oro-Mediterranean coniferous. The excessive cutting, wrong silvicultural practices, opening of agricultural fields inside the forests, and clear-cutting system are changing the vegetation structure of forests. Some of the forests in the country are accepted as relict forests. (C) 2013 The Authors. Published by Elsevier Ltd.