Boreal Cordillera

From Wikipedia, the free encyclopedia

The Boreal Cordillera is a Canadian terrestrial ecozone occupying most of the northern third of British Columbia and southern half of the Yukon. Within it is found Kluane National Park and Reserve, and a small portion of the southern range of Nahanni National Park Reserve.[1] Most of the area's population is based in the city of Whitehorse, and it contains most of the Yukon's population. The portion in British Columbia is not that populated.[2]

The main economic activity is mining, particularly of gold, which discovery in the region led to the Klondike Gold Rush.[3] In addition to the area's rich mineral deposits, active industries exist in forestry, tourism, and hydroelectric power generation.[4]

[edit] Geography

This mountainous region is between the Montane Cordillera to the south and the Taiga Cordillera to the north. The three zones contain the Canadian Rockies. To the east are the Taiga Plains, and to the west is Alaska, though the ecozone is also adjacent to narrow strips of the Pacific Maritime. It is characterised by tall peaks and extensive plateaux.[5] The plateaux have a fairly gentle terrain, broken by numerous watercourses running through them, and are separated by wide valleys and their lowlands.[4]

Just over 15% of the Boreal Cordillera, or roughly 73,320 km² consists of wetlands, of which 92% is treed wetland.[6] It covers a total area of 471,400 km², with 241,240 km² of forest cover, of which 78.6% is softwood, 17.8% is mixedwood, and 3.6 is hardwood.[6] The spruce beetle has been proliferating since the 1990s, and has destroyed vast areas of the spruce forest. The ecozone contains four forest regions - tundra, sub-alpine, coast, and boreal.[7] There is also concern that the softwood harvest in southeastern Yukon does not have adequate natural regeneration.[8]

[edit] Climate

The interior intermontane plateau receive about 400 mm of annual precipitation, much less than the 1000 to 1500 mm levels in the eastern mountains, and the even higher levels in the western mountains.[5] Snowfall accounts for 35 to 60% of all precipitation.[9] Winters are long and cold, with January mean temperatures between -15ºC and -27ºC. Summers are warm but short, with July mean temperatures between 12ºC and 15ºC.[5]

Alpine weather is more typical beyond the tree line at elevations above 1000 m, where frost can develop year-round.[9] Average temperatures here remain below freezing for most of the year, and snowfall accounts for at least 70% of precipitation.[9] Permafrost is typical in these regions, allowing for the growth of only shrubs, mosses and lichens.[10]

Sudden violent storms are possible in the area during the summer, usually due to moist air masses arriving from the Pacific Ocean.[9] Usually, however, the Pacific moderates the climate in this ecozone.

The Cordillera receives a lot of precipitation it is mostly rain but when it snows it melts very quickly.

[edit] References=

  1. ^ Nahanni National Park Reserve of Canada. Parks Canada. Retrieved on 2008-02-07.
  2. ^ "Klondike Country". Boreal Cordillera Ecozone. Environment Canada. Retrieved on 2008-02-07.
  3. ^ Bernhardt, Torsten. Boreal Cordillera. Canada's Ecozones, Canadian Biodiversity project. McGill University, Redpath Museum. Retrieved on 2008-02-07.
  4. ^ a b Forest Ecozones of Canada. Natural Resources Canada. Retrieved on 2008-02-07.
  5. ^ a b c Boreal Cordillera Ecozone. Parks Canada. Retrieved on 2008-02-07.
  6. ^ a b Indicator 1.1.1 - Area of forest, by type and age class,and wetlands in each ecozone. Criteria and Indicators of Sustainable Forest Management in Canada, National Status 2005. Canadian Council of Forest Ministers (2005). Retrieved on 2008-02-07.
  7. ^ Table 1. Forest Regions and Principal Tree Species by Ecozone. Atlas of Canada. Retrieved on 2008-02-07.
  8. ^ Boreal Cordillera Ecozone. Forest Conditions - Ecozone Reports. Natural Resources Canada. Retrieved on 2008-02-07.
  9. ^ a b c d Landforms and Climate of the Boreal Cordillera Ecozone. Boreal Cordillera Ecozone. Environment Canada. Retrieved on 2008-02-07.
  10. ^ Canada's Ecozones. Space for Species. Retrieved on 2008-02-07.