North America Cold Biomes

David LeBlancEd White

Arctic Tundra

David LeBlanc

Gates of the Arctic National Park, Brooks Range, Alaska.

Dominant plants are low-lying shrubs, grasses, and forbs with scattered stunted trees.www.bsu.edu/biology/leblanc

Anuktuvuk Pass, Brooks Range, Alaska.

Further north no trees at all, just low-lying shrubs, grasses and forbs.68o 03’ 42.98” N, 151o 58’ 12.81” W

Note: This is an example of an image that displays characteristics of dominant plant species.

Note: This is an example of an image that displays landscape scale characteristics.

Arctic Tundra: Climate

Short, cool frost-free growing season limits Pnet and growth of trees.

Extreme, cold winters. Low-lying shrubs, grasses,

forbs dominate b/c they are protected under snow during winter.

Trees not present b/c little or no growing season to produce wood and they cannot survive harsh winter conditions.

Climate Change:Warmer Only

Increased Temperature but w/ same Precipitation

Winters would be less severe, BUT entire growing season would be too dry to support plant growth

Vegetation becomes Cold Desert.

Climate Change: Warmer & Wetter

Increased Temperature AND Precipitation

Winters less severe Growing season warmer &

longer but precipitation adequate only at beginning and end, droughts in some years.

w/ short growing season vegetation remains tundra or becomes sparse, stunted boreal forest.

Boreal Forest

Ed White

Banff National Park, Alberta, Canada.

Dominant plants are evergreen trees.www.bsu.edu/biology/leblanc

Chutes-des-Passes, Lac St. John, Quebec.

Boreal forest dominated by evergreen trees (spruce and fir).49o 50’ 49.70” N, 71o 11’ 42.39” W

Boreal Forest Climate

Short, cool frost-free growing season limits Pnet

Long, cold winters. No dry months; fire unlikely. Evergreen conifer trees able to

extend growing season by photosynthesizing on warm days in Spring and Fall.

Evergreen conifer foliage better able to retain heat during cool growing season, increasing Pnet..

Climate Change:Warmer Only

Increased Temperature but w/ same Precipitation

Winters would be less severe and frost-free growing season longer.

Precipitation probably adequate to support growth during growing season, but droughts and fire may become more frequent

Vegetation may shift to Temperate Deciduous Forest

Climate Change:Warmer & Wetter

Increased Temperature AND Precipitation

Winters less severe Growing season warmer and

longer with much precipitation and no droughts.

Vegetation becomes Temperate Deciduous Forest.

Climate Change Summary

In tundra, cold temperature becomes less limiting, but drought stress increases; vegetation shifts from cold-limited to drought-limited cold desert.

In boreal forest, cold temperature becomes less limiting and growing season expands. W/ adequate water availability vegetation will shift from evergreen trees to temperate deciduous trees.