Scrub is the most abundant habitat on the Karst plateau. It established itself rapidly after World War II with the abandonment of grazing. This formation is the product of the degradation of ancient karstic forests, consisting mainly of sessile oak (Quercus petraea) and Turkey oak (Quercus cerris). Its composition reflects the geological and environmental characteristics present in a large part of the Karst , where the reduced terrigenous layer and the permeability of the rocky substratum are some of the factors that determine the development of a sparse tree cover, characterised mostly by specimens with a tall shrub rather than arboreal character, with a low woody growing stock. The arboreal layer is in fact represented by elements with slender stems and reduced vertical development. Illyrian species such as the hornbeam (Ostrya carpinifolia), manna ash (Fraxinus ornus), field maple (Acer campestre) and Montpelier maple (Acer monspessulanum) are dominant. The shrub layer, influenced by the considerable light penetration, consists of species such as dogwood (Cornus mas), dog cherry (Prunus mahaleb) and European smoke-bush (Cotinus coggygria). The low density of tree species, which characterises Karst scrubland, allows the development of a rich herbaceous layer in which autumn moor-grass (Sesleria autumnalis) dominates, but there are also showy species such as the wild peony (Paeonia officinalis) and the dittany (Dictamnus albus).