[2] The Trnovo Forest Plateau has a karst character, without surface watercourses and broken up by closed valleys, outcroppings, hills, caves, shafts, and smaller karst features: solution pans, rills, karrens, and other features.

The vegetation inversion at Big Paradana Ice Cave (Slovene: Velika ledena jama v Paradani) in the eastern part of the plateau, measuring 385 meters (1,263 ft) by 1,550 meters (5,090 ft), is a locus classicus and in the past ice was harvested from it and exported via Gorizia and Trieste to Egypt.

The north side of the plateau shows tectonic formation along the Idrija Fault oriented in the Dinaric direction,[5] and the south side shows the results of tectonic thrusting of Mesozoic limestone and dolomite over younger Eocene flysch.

Two-thirds of the surface is covered by limestone, one-fourth by dolomite, and the remainder is flysch and loose material.

The bora wind is a typical weather phenomenon, blowing down from the plateau towards the sea with gusts often exceeding 100 kilometers per hour (62 mph).

The highest vegetation is on Little Mount Golak (1,495 meters or 4,905 feet), which is bare at the summit, below which grow dwarf willow (Salix sp.)

Protected flora grows in the rocky crevices, including the Carniolan primrose (Primula carniolica).

The substantial precipitation quickly erodes the soil, and it is also carried away by the bora wind in exposed locations.

The settlements were formed through more recent high-elevation colonization, and the dominant patterns are clustered villages and isolated farms.