Flysch (interchanging layers of marl and sandstone) which is 35 million years old in this area is constantly exposed to weathering and thus producing fertile soil especially suitable for wine-growing.

Vineyards in Brda are mostly located on terraced slopes interspersed with patches of woods where black locust (Robinia pseudoacacia) for vineyard poles is growing and where game and singing birds find shelter. Oaks used to be the most common trees in the area (one of the largest oaks can be seen in Drnovk village) while in the northwestern part of Brda around Kožbana chestnut is still characteristic, also the marron, an important food source for many generations in remote villages along the border.

Despite cultivated landscape, diverse plant life can be observed everywhere in Brda, from auricula (which is otherwise an Alpine flower) along the Idrija river to colorful meadows on Korada where numerous orchids and other rare, endangered and thus protected plant species grow throughout the year. Caves are a rarity in Brda since this is not a karst landscape. To find caves, you have to ask older locals. Otherwise, you can visit Krčnik, a natural stone bridge, and the Korita gorge on the Kožbanjšček creek near the villages of Hruševlje and Pristavo.