Three high-mountain tree species from the Pinaceae family were investigated: Serbian spruce, Picea omorika (Pan?.) Pürkyne, Bosnian pine, Pinus heldreichii Christ., and Macedonian pine, Pinus peuce Griseb. Although they belong to different subfamilies (Abietoideae and Pinoideae), genera (Picea and Pinus), subgenera (Pinus and Strobus), and have clear morphological differences, all three species, which are autochthonous in Serbia and Balkan Peninsula, have several common features: endemic-relic character, disjunctive area of distribution, higher or lower vulnerability (IUCN Red lists), under-investigated variability as well as taxonomic, phylogenetic, and conservation statuses. Since Serbian spruce, Bosnian and Macedonian pine, as well as some other relict gymnosperms from Balkans, are important links for the understanding of the phylogenetic relations between the fossil and contemporary species belonging to the genera Picea, Pinus, and other conifer trees, study of their variability is of special significance for the understanding of the biogeography, taxonomy, phylogeny, and evolution of plant species.
P. omorika exhibited the highest abundance in O-containing mono- and sesquiterpenes, but a lower abundance in hydrocarbons, especially in sesquiterpenes. P. heldreichii showed the highest abundance of sesquiterpene hydrocarbons and the lowest for O-containing monoterpenes. P. peuce contained the highest amounts of monoterpene hydrocarbons and significant amounts of O-containing monoterpenes. The range of n-alkanes was wider in P. omorika (C18–C35) than in P. heldreichii and P. peuce (C18–C33). The dominant n-alkanes were C29 in the needle waxes of P. omorika, C23, C27, and C25 in those of P. heldreichii, and C29, C25, C27, and C23 in those of P. peuce. The waxes of P. omorika contained higher amounts of n-alkanes C29, C31, and C33 , while those of P. heldreichii and P. peuce had higher contents of n-alkanes C21, C22, C23, C24, and C26.
It is well known that Picea and Pinus are treated as separate genera on the basis of several, mainly morphological characters. However, in spite the fact that inter- and intrapopulation variability in the terpene and n-alkane composition of the needle waxes has been shown, a very clear separation of these genera was demonstrated. Thus, it can be concluded that these characters (terpenes and n-alkanes,) are also of great importance in the overall consideration of phytogeographic, evolutionary, chemotaxonomic, and phylogenetic aspects of these interesting conifer taxa.