The entire border between Greece and Bulgaria is formed by the heavily forested, sparsely populated Rhodopi range, which is among the last real (and vast) wilderness areas in Europe.
The area north of Xanthi and east to the river valley area west of Komotini, is important habitat for birds of prey and forest birds. The vegetation is oak scrub, oak woods, and higher up, some conifers. The forest along the river valley of the Kompsatos has breeding black storks and sparrowhawks, though both birds aren't easy to see. Three kinds of eagles are easier to find, but higher up. A good place to see both Egyptian and griffon vultures and peregrines is in a gorge of the same river, just east of Iasmos where the river crosses the road, as well as other birds. This general area is approached by lesser roads either to the north of the road between Xanthi and Komotini, or up the Kompsatos River from Iasmos.