While the southern slopes of the Alborz Mountains are usually semiarid or arid, with irregular and low precipitation, the northern slopes of the range are usually humid, especially in the western parts of the Central Alborz. In the southern slopes or the Elburz Range forest steppe ecoregion, the higher elevations are arid with few trees. Juniper is the most common tree in inaccessible areas and at high elevation, while common shrubs are pistachio, maple, and almond. But in the northern slopes, the Caspian Hyrcanian mixed forests ecoregion is lush and forested. The natural vegetation of this region grows in distinct zones: the Hyrcanian forests on the lowest levels, beech forests in the middle zone, and oak forests in higher regions. The wild cypress is the dominant form of vegetation in some valleys, while olive trees grow in the western valleys of the Central Alborz near the Sefidrud. The bezoar ibex, Blanford's fox, Rüppell's fox, red fox, Persian fallow deer, wild boar, Syrian brown bear, Persian leopard, Indian wolf, buzzard, goose, woodpecker, griffon vulture, and eagle are among important animals and birds found in the Alborz Mountains. The extinct Caspian tiger also lived in the Alborz Mountains.