page_title: Sierra Nevada subalpine zone
section_title: Other environmental issues
hierarchical_section_title: Sierra Nevada subalpine zone / Environmental issues / Other environmental issues
caption_attribution_description: English: Thousand Island Lake (2997m) and Banner Peak (3943m), looking southwest from John Muir Trail/Pacific Crest Trail at 3080m, in the Ansel Adams Wilderness of the Sierra Nevada, California. Français&#160;: Le Thousand Island Lake (Trad.&#160;: «&#160;Lac aux mille iles&#160;») et le Banner Peak (Trad.&#160;: «&#160;Pic Banner&#160;»), vus depuis le John Muir Trail Pacific Crest Trail (Trad.&#160;: «&#160;tronçon commun entre le Sentier John Muir et Sentrier des Crêtes du Pacifique&#160;»). L'ensemble de ce paysage fait partie de la Ansel Adams Wilderness (Trad.&#160;: «&#160;рréserve intégrale Ansel Adams&#160;») dans la Sierre Nevada, en Californie.
context_page_description: 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 at its lower limit, and tree line at its upper limit.
  The Sierra Nevada subalpine zone occurs between 2,450–3,660 metres, 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.
context_section_description: The isolation and restricted use of subalpine systems keep them relatively free of recreational impacts.  The harsh climate also makes these systems robust against biological invasion and disease.  Most exotic plants in California are currently restricted to low elevations, although some invasives may have the potential to reach subalpine. If climate change does indeed warm regions where subalpine occurs, conditions there may become more conducive to threats such as invasive species and disease.
caption: Subalpine zone near Banner Peak, Ansel Adams Wilderness
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