Some botanists treat Bulgarian Fir and Sicilian Fir as varieties of Silver Fir, as A. alba var.

Much of the area is forested, with the best conifer woods in Bulgaria, holding important populations of the Balkan endemic species Macedonian Pine, Bosnian Pine and Bulgarian Fir.

Abies borisii-regis (Bulgarian Fir) is a species of fir native to the mountains of the Balkan Peninsula, in Bulgaria, northern Greece, the Republic of Macedonia, Albania and Serbia.

Greek Fir (Abies cephalonica) is a fir native to the mountains of Greece, primarily in the Peloponnesos and the island of Kefallonia, intergrading with the closely related Bulgarian Fir further north in the Pindus mountains of northern Greece.

The forests are made up mainly of Norway Spruce and Bulgarian Fir, with some Macedonian Pine, Scots Pine, and at the tree-line, Mountain Pine, and mixed deciduous forest at lower altitudes, mainly beech, birch, aspen and alder.

Musala is situated within the Rila National Park, which is noted for its rich flora, including species such as Macedonian Pine and Bulgarian Fir in the forests on its middle slopes, and fauna; it is one of the easiest places in Europe to see the wallcreeper.