||The examined area mainly lies in the northeastern part of the Prefecture of Arta and is the natural boundary between Ipeiros and Thessalia regions. It is one of the longest and most remote parts of the southern Pindos mountain range. From a geological point of view, Ori Athamanon mountains belong to the Olonos-Pindos zone and their main substrate is limestone with sporadic appearance of flysch. They consist of a continuous ridge with a NW-SE direction, and the highest peak is that of Katafidi at 2393 m altitude. The mountain slopes are crossed by many springs and small streams. The main stream is known as "Rema tis Kranias" and under the name of Melissourgiotikos, flows into the river Kallaritikos which is one of the Arachtos river tributaries. Two attractive waterfalls also occur in the area, one near Katarraktis village and the other near the village of Theodoriana. Two grassy plateaux, are also on the eastern side of Mt. Tzoumerka, named Epano Kostelata and Kato Kostelata, are used by the locals as pastures. In the past the Ori Athamanon mountains were densely forested, however, in recent years they have suffered from irrational deforestation due to excessive wood-cutting, tree-felling and grazing. For this reason extensive bare places occur in the area. Despite this, however, we can still find well-forested slopes with coniferous forests (where Taxus baccata exists in small stands or as isolated trees) and broad-leaved deciduous forests.