British Columbia by Richard Cannings

British Columbia by Richard Cannings

Author:Richard Cannings
Language: eng
Format: epub
ISBN: 978-1-77164-074-9
Publisher: Greystone Books
Published: 2015-01-19T16:00:00+00:00


Northern Timberline: The Shrub Tundra

The subalpine zone in northern British Columbia (north of Williston Lake) is characterized by tall willow and birch shrubs. Although these shrubs can be difficult to walk through, hikers resting in small openings in the cover are rewarded with flowers typical of the spruce forests below, such as Tall Bluebells, ragwort, larkspur, monkshood and shootingstars. As you break out into the open alpine zone, the ground is carpeted with blueberries and Alpine Bearberries. In late summer and fall the bearberry leaves turn colour and paint the mountainsides a brilliant crimson. This biogeoclimatic zone, the Spruce-Willow-Birch zone, is threatened by climate change. As temperatures warm through this century, almost half of the province’s shrub tundra is projected to be replaced by boreal forest moving upslope and by the southern subalpine zone—the Engelmann Spruce–Subalpine Fir Zone—moving north.

Northern subalpine valleys often have two timberlines—one on the mountain ridges and another just above the valley bottom. These lower timberlines are found in wide valleys where heavy, frigid air collects in the bottomlands. This ponding of cold air significantly lowers temperatures throughout the year and can often result in permafrost conditions in the valleys. Such valleys are filled with shrubs, grasslands and fens and provide the only breeding habitat in the province for Gray-cheeked Thrushes and Smith’s Longspurs.



Download



Copyright Disclaimer:
This site does not store any files on its server. We only index and link to content provided by other sites. Please contact the content providers to delete copyright contents if any and email us, we'll remove relevant links or contents immediately.