Over 1,700 species of plants have been recorded on Mount Olympus which represent 25% of all Greek flora. Most of those plants exist in low altitudes. They are the usual Mediterranean and centre-European kinds. In the treeless alpine zone there are 150 kinds of plants. Half of those can be found only in the Balkan Peninsula and 23 are native and are as follows:
Achillea ambrosiaca, Alyssum handelii, Asperula muscosa, Aubrieta thessala,
Campanula oreadum, Carum adamovicii, Centaurea incomplete, Centaurea litochorea,
Centaurea transies, Cerastium theophrasti, Coincla nivalis, Erysimum olympicum,
Festuca olympica, Genista sakellariadis, Jankaea heldreichii, Ligusticum
olympicum, Melampyrus ciliatum, Ophrys helenae, Poa thessala, Potentilla deorum,
Silene oligantha, Viola striis - notata, Viola pseudograeca
The tree-fossil, Jankaea heldreichii, from the glacial era presents great interest to the scientists.
Due to the bold stark terrain, the close proximity to the sea and the creation of many micro-environments the vegetation, particularly on the east slopes, of Mount Olympus is characterised by a wide range of vegetation zones. Generally speaking there are four vegetation zones with many additional types of vegetation spanning from one to the other.
The first zone from 300 to 500 m includes mainly short bushes and trees such as the most common kinds of holm oak (Quercus ilex), Greek strawberry tree (Arbutus adrachnae),kermes oak (Quercus coccifera), strawberry tree (Arbutus unedo), cedar (Juniperus oxycedrus). There are also certain kinds of deciduous trees: flowering ash (Fraxinus ornus), Montpellier maple (Acer monspessulanum), Judas tree (Cercis siliquastrum), turpentine tree (Pistacia terebinthus), etc.
From 600 to 1400 m we have the second zone. The vegetation is mainly dominated by the European black pine (Pinus nigra var. Pallasiana), that forms massive clumps.
In smaller groups appear: King Boris’s fir (Abies hybridogenus), beech tree (Facus moesiaca), few wych elm (Ulmus glabra), yew (Taxus baccata), wild cherry (Prunus cerasifera), hazel (Coryllus avellana), cornelian cherry (Cornus mas) and a significant selection of mossy plants. The ravines and the gullies are covered with oriental plane (Platanus orientalis), grey sallow (Salix cinerea), alder wood (Alnus glutinosa) and riparian vegetation.
From 1400 to 2500 m we have the cold-hardy conifers zone in which the conifers start to appear with the rare pine Pinus heldreichii being the most predominant. It appears from 1100 m, replaces the black pine gradually and creates an unmixed with any other trees forest up to 2000 m. In this particular zone we also have shrubs and grass plants, while the flora includes many endemic species of the Balkans.
Over 2500 m which is the highest forest limit in the Balkans there is no more forest just a variety of alpine ecosystems of low vegetation with many rare wild flowers of which the majority are native to the flora of Greece and the Balkans.
Thirty- two species of mammals have been recorded on Mount Olympus the most common being the chamois (Rupicapra rupicapra), deer (Capreolus capreolus), wolf (Canis lupus) wild pig (Sus scrofa), fox (Vulpes vulpes), ferret (Martes foina), squirrel (Sciurus vulgaris), jackal (Canis aureus), wild cat (Felis sylvestris), etc. Furthermore 108 species of bird have been recorded which find refuge in the dense forests and the sheer rocky mountain slopes.
Some of these species of fauna are under threat such as the chamois, golden eagle (Aquila chrysaetos) and the rare woodpecker and are strictly protected under international agreements. Additionally the streams and the small lakes are home to a significant number of amphibians and reptiles and a vast number of butterflies for which Olympus is famous.