The flora of Dilijan National Park includes 902 species of
vascular plants, namely
Lycopodium (1 species),
Horse-tails (1),
ferns (12),
gymnosperms (7) and
angiosperms (881). About 40 rare species of plants occur in this territory. 29 species of the flora are registered in the
Red Book of Endangered Species of Armenia and 4 in the Red Data Book of the
USSR. The vegetation of the national park is of
mesophilous Caucasian type mainly represented by forest associations. It mainly consists of
deciduous species such as
oaks (
Quercus petraea subsp. polycarpa, Q. macranthera),
Oriental beech (
Fagus orientalis),
common and
Oriental hornbeam (
Carpinus betulus, Carpinus orientalis), which form homogeneous oak, beech and hornbeam forests as well as mixed forests with different combinations of the species mentioned. Georgian oak (
Quercus petraea subsp. polycarpa) forests occur on the southern slopes of the middle forest zone and oriental beech forests on the northern slopes. In the upper zone forest consists of
Q. macranthera. Hornbeam occurs mainly in mixed forests. Oriental hornbeam reaches up to 1500 m above sea level, while common hornbeam spreading all over the forest zone up to 2000 m. Different species of
lime (
Tilia),
maple (
Acer) and
ash (
Fraxinus) grow in the middle forest zone and especially the upper limit of higher forest zone.
Coniferous forests (
pine -
Pinus,
juniper -
Juniperus and
yew -
Taxus) occupy a limited territory in the national park and occur in patches.
Pine often makes dense forests in the basin of the River Hovajur on the slopes of the Areguni and Pambak ranges in the vicinity of serpentine Dilijan highway. There are many pine trees in Dilijan and on nearby slopes. Juniper sparse forests spread in the valley of the River Getik especially near the river mouth as well as on the dry slopes of the Ijevan Mountains.
Juniperus foetidissima is the most predominant species among four juniper species occurring in the national park. There are well conserved juniper stands on the rocky slopes of Mount Abeghakhar in the basin of the River Aghstev. The forests in the national park are rich in fruit trees and bushes such as
oriental apple -
Malus orientalis,
walnut -
Juglans regia,
cornel -
Cornus mas,
plum -
Prunus spp.,
blackthorn -
Prunus spinosa,
pear -
Pyrus communis, gooseberry -
Ribes uva-crispa, medlar -
Mespilus germanica,
common hazelnut -
Corylus avellana (see also Hazelnut Reservation), various species of Blackcurrant -
Ribes spp., and
hawthorn -
Crataegus spp. Many species occurring in the national park are well known as medicinal plants (
Saint John's wort -
Hypericum spp.,
mint -
Mentha,
thyme -
Thymus,
ziziphora -
Ziziphora, etc.), edible plants (
sorrel -
Rumex,
falcaria -
Falcaria,
cow parsnip -
Heracleum, etc.), forage (
clover -
Trifolium,
sainfoin -
Onobrychis,
sea-holly -
Eryngium, etc.) or decorative plants (
iris,
orchids, etc.). The western rocky slopes of the Ijevan mountain range and Mount Abeghasar are rich in petrophytes and rare plants. Rocks and cliffs serves as a favorable habitat for numerous rare species such as Armenian Saint John's wort (
Hypericum armenum),
saxifrage (
Saxifraga juniperifolia,
S. tridactylites), scorzonera (
Scorzonera rigida), cephalaria (
Cephalaria media),
small scabious (
Scabiosa columbaria),
wild jasmine (
Jasminum fruticans) and others. Mount Abeghasar is especially rich in rare species. Tertiary
relict yew and
Caucasian rhododendron (
Rhododendron caucasicum) are the gems of the national park. The small well conserved yew forest located in the basin of the River Polad was designated as a reservation in 1958 (
see Akhnabat Yew Grove Reservation). The second smaller yew forest has been located on the upper stream of the River Aghstev in the gorge Frolova Balka of the Pambak Mountains. Botanists N. Troitski in 1939 and A. Takhtajan in 1954 reported that this younger forest consisting of 100- to 180-, sometimes 220-year-old trees stretched for 4–5 km from the seventh kilometer of Dilijan highway towards Fioletovo village. N. Troitski mentioned also that in the past yew was more abundant. At present, only the remnants of previous dense forest have survived in the form of individual trees in an inaccessible terrain. Groups of yew trees and individual trees occur also over the whole territory of the national park. Relict species Caucasian rhododendron is also noteworthy, growing on the northern slopes of the Pambak mountains. Rhododendron occurs in the moist meadow vegetation of subalpine zone and stretches westward to Mount Ampasar (the Pambak mountain range) where the largest rhododendron area of Armenia is situated (see Rhododendron Reservation). ==Fauna==