Khosrov Forest State Reserve pear ("Pyrus"), rowan ("Sorbus"). The southern steep sunny and dry slopes are covered by juniper sparse forests. Caucasian oak ("Quercus macranthera") forests can be found at an altitude of 1600–2300 m above sea level, which are rather dense in Khosrov district of the reserve known as "Trchnaberd". Oak forests are accompanied by ash ("Fraxinus excelsior", "Fraxinus rotundifolia"), rowan ("Sorbus aucuparia"), pear ("Pyrus"), maple ("Acer") and others. Bushes are abundant in the forests, represented by different species of wayfaring tree ("Viburnum lantana"), honeysuckle ("Lonicera"), rose ("Rosa"), hawthorn ("Crataegus"). The vegetation in the forests is rich in grass (family "Poaceae" L.). Mountainous
Sorbus aucuparia which is a hybrid with "Sorbus aria". The main pests for "S. aucuparia" are the apple fruit moth "Argyresthia conjugella" and the mountain-ash sawfly "Hoplocampa alpina". The rust fungus "Gymnosporangium cornutum" produces leaf galls. The leaves are not palatable to insects, but are used by insect larvae, including by the moth "Venusia cambrica", the case-bearer moth "Coleophora anatipennella", and leaf miners of the genus "Stigmella". The snail "Helix aspersa" feeds on the leaves. The plant can suffer from fire blight. Fossils of "Sorbus aucuparia" have been described from the fossil flora of Kızılcahamam district in Turkey, which is of early