Dolines represent one of the most typical phenomena of surface karstification. 

They are basins, the formation of which occurs as a consequence of the dissolution of limestone by rainwater. The waters, flowing both on the surface and at depth, dissolve the limestone, widening the fissures that gradually join together, forming a depression in the ground. In other cases, the depression may be created as a result of the collapse of the vault of a cave close to the surface. 

The bottoms of dolines are rich in iron and aluminium compounds that give the soil a typical reddish-brown colour, called terra rossa. These red soils have the characteristic of being particularly fertile. 

Sinkholes are characterised by the phenomenon of thermal inversion, i.e. cold, dense air stagnates at the bottom where the temperature is therefore lower than in the surrounding area. 

The special physical and climatic characteristics of the sinkhole have allowed the survival of plant species that appeared on the Karst plateau in the post-glacial period. They disappeared from the plateau as a result of the increase in temperatures, but survived at the bottom of the dolines and in the Karst mountains. 

One of the tree species that can be encountered in these environments is the hornbeam (Carpinus betulus), which is not normally found on the Karst plateau as it is very sensitive to periods of drought. In the undergrowth, the asarum or European wild ginger(Asarum europaeum) is present. These two species together give their name to the plant association specific to the doline: Asaro-Carpinetum betuli.  

In the undergrowth, dog's tooth violet (Erythronium dens-canis), spring pea (Lathyrus vernus), wood anemone (Anemone nemorosa), isopyrum (Isopyrum thalictroides) and two-leaved squill (Scilla bifolia) are present.