Koru Polje and its close surroundings lie at an elevation of about 1450 to 2000m in the middle part of the Kure Mountains (the western part of the Northern Anatolia Orogenic Belt). Various karst landforms characteristic of the temperate climatic zone can be seen in this area, which is generally rainy throughout the year, with an annual precipitation of more than 1600mm, cool winter and mild summer temperatures, and an average annual temperature below 7°C. The study area is entirely within the forest zone and its karstic landforms are developed under soil and plant cover. Large closed depressions like Koru Polje and the Subatanyaylasi Depression are shaped by fluviokarstic processes. Quaternary climate changes affected the evolution of large karstic landforms in the study area. Periglacial conditions prevailed during Quaternary cold periods and development of surface karst landforms was interrupted at these times. In warm periods after the release of permafrost, surface water sank into reactivated swallow holes. Thus, karst landform evolution in the study area accelerated during the warmer periods of the Quaternary, and during recent times. © British Cave Research Association, 2005.