Pirgulu State Reserve, Protected area in Shamakhi District, Azerbaijan

Pirgulu State Reserve covers 4,274 hectares on the southeastern slopes of the Greater Caucasus, in the mountain forests of the Shamakhi and Agsu districts. Beech woods make up 57% of the tree cover, oaks about 24% and hornbeam close to 18%, with willow, maple and ash also present. The terrain is cut into three parts by mountain valleys and deep gorges, and the ground is brown mountain-forest and carbonate mountain-forest soil.

Pirgulu State Reserve was created on 25 December 1968 on mountain-forest land of the Aghsu and Shamakhi districts, covering 1,521 hectares. In January 2003 its territory was enlarged by 2,753 hectares to 4,274 hectares. The reserve was founded to protect mountain-forest landscapes and plant cover and to prevent air pollution harmful to the astroclimate of the observatory operating there.

The reserve's forests are dominated by hornbeam (57%), oak (24%) and beech (about 18%), with willow, maple and ash also present. The undergrowth is mostly shrubs rather than continuous grass, and about 45 rare or declining plant species grow here. Look for the brown bear, lynx and black grouse, all listed in the Red Book.

The reserve lies on the south-eastern slopes of the Greater Caucasus in the Shamakhi and Agsu districts, and its terrain is split into three parts by mountain valleys and deep gorges. The area was enlarged by 2,753 ha in January 2003, reaching 4,274 ha. A stationary observation laboratory of the Institute of Geography, named after academician H. A. Aliyev, has operated on the site since 1970.

The reserve's natural conditions directly affect air quality around a major astronomical observatory nearby. This connection between the forest ecosystem and scientific observation makes it an unusual protected area.