Yellow Cedar felled on Vancouver Island
The yellow cedar, a tree that grows only on the Pacific Coast of North America, is known for its durable wood that has been valuable to construction and boat building. Yellow-cedar is a member of the cypress family and is related to only six other species worldwide.
In the late 1980s, studies were done on the decline of yellow cedar in British Columbia. Why were the trees dying? The lack of snowfall or a warmer than normal winter followed by a cold snap leaves the tree’s shallow roots vulnerable to damage. Yellow cedars are one of the first trees to be ready to grow as soon as the winter changes. Normally, a few degrees warmer meant that spring has arrived. Not anymore. Periods of late winter thawing followed by freezing temperatures have become more frequent and as this trend of unpredictable weather patterns repeat year after year, the tree cannot recover and it dies.
Over time, the researchers came to identify certain symptoms: first the fine roots would die then small diameter roots die, followed by formation of necrotic lesions on coarse roots, and finally necrotic lesions spread from dead roots vertically from the root collar up the side of the bole. Crown symptoms occur after the early root symptoms. Crowns generally died as a unit with proximal foliage dying first, then as trees finally died, distal foliage died.
Over time, the numbers of yellow cedar kept creeping higher with thousands of hectares of dead and dying yellow cedars. Today, the species is in peril. According to a recent report by the U.S. Forest Service:
Current research emphasis in Alaska is on the contributing roles of hydrology, soil chemistry, air and soil temperature, snowpack, freezing injury, and climate. The susceptibility of yellow-cedar to spring freezing injury in areas of little snowpack forms a leading hypothesis for this forest decline
(Hennon and Shaw 1994). Yellow-cedar is thought to be susceptible to frost injury, particularly in areas where soil is not protected from freezing by snow.… Information on the process that damages yellow-cedar trees in British Columbia and Alaska is needed to develop a management strategy for this valuable species tailored to areas where it is dying now, where it is expected to die in the future in a warming climate…
This is my contribution to blog action day.org 
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