In order to analyse the developmental characteristics of individual fir trees (Abies alba) in tri-dominant forests of beech, fir and spruce (Piceeto-Abieti-Fagetum s. lat.) on Mt. Ljubišnja, eight dominant fir trees were felled. Felling four trees from the experimental field that has been set near the village of Vrba (Vukodol site), which is on a limestone base, and four trees from experimental field in the vicinity of the mining village of Sula, situated on basic eruptives, together with further stem analysis of such trees, gave us important conclusions about the basic characteristics of fir growth in these forest communities. This provided insight into the relations and impact of habitat characteristics to the development of fir trees in mixed stands of beech, fir and spruce on Mt. Ljubišnja. By studying the pattern of development of those trees, it was determined that the slow growth (socalled vegetative time) period lasted longer in trees from the Vukodol site, on the limestone soils. The results confirmed that fir trees at a very advanced age could have a good height and volume increment. The average increment of fir culminated very late. These facts may be applicable in designing management goals for these and similar stands