The Sierra Nevada subalpine zone refers to a biotic zone below treeline in the Sierra Nevada mountain range of California, United States. This subalpine zone is positioned between the upper montane zone (such as red fir forest) at its lower limit, and tree line at its upper limit. The Sierra Nevada subalpine zone occurs between 2,450–3,660 metres (8,000–12,000 ft), and is characterized by an open woodland of several conifer species, including whitebark pine, lodgepole pine, western white pine, mountain hemlock, and Sierra juniper. The vegetation and ecology is determined by the harsh climate, with extensive snow and wind. In addition, soils are thin and nutrient-poor. Due to these harsh conditions, vegetation grows slowly and to reduced heights. In addition, the stressful environment suppress species competition and promotes mutualism. The marginal conditions make the Sierra Nevada subalpine zone sensitive to environmental changes, such as climate change and pollution. The long-lived nature of the subalpine species make the zone a good study system to examine these effects. (en)