In the upper submontane vegetation belt, which in the higher areas of this mountain forest region directly connects to the lower mountain belt, life conditions are even more adverse. The temperatures are even lower, snow mantel stays much longer and thus is the vegetation period much shorter.
In the mountains of western Croatia the most significant is the Aceri-Fagetum community (the submontane beech forest). In the belt of these forests, in some parts of south-western Croatia grows the Calamagrosti-Abietetum community.
In the area of Croatian krast develops a special community-Picetum illyricum subalpinum (submontane fir forests).
Of course, in this submontane area, on bigger or smaller areas, except forest vegetation there are other, mostly endemic vegetation communities. Some of them create the vegetation of submontane swards, some the vegetation of subalpine high herbaceous vegetation and some are confined to rifts in rocks or steep limestone rubble etc.
