For more than a century, yellow cedars in Alaska and British Columbia have been dying, yet it was recently confirmed by U.S. Forest Service researchers that the cause was due to climate change.
Yellow cedars are known to be hardy trees that can live up to 1,000 years. However, yellow cedars have shallow roots which make them susceptible to freezing. With climate change, there has been less snow on the ground to insulate the shallow roots from extreme temperatures. And with less snow on the ground, frozen roots have led to the decline of 60 to 70 percent of trees covering 600,000 acres in Alaska and British Columbia. Climate models predict that over time, there will be less snow fall yet periods of extreme cold weather in coastal Alaska which could lead to the decline of even more yellow cedars in that area.
For a long time, tree pathologists were confused as to what was causing the deaths of yellow cedars. Tree pathologists ruled out organisms and fungi as being the cause and focused on factors such as hydrology and soil temperatures, eventually coming to the conclusion that lack of snow covering was causing the tree’s roots to freeze. Nevertheless, yellow cedars are strong trees that are able to withstand bugs, injury, and rot. Given its hardy nature, Native Alaskans – Haida, Tlingit, and Tsimshian – used the wood to make items such as canoe paddles, dishes, totem poles and woven items. Yellow cedar is still used to build boats, and in Japan, the wood is highly valued for its age, color, durability, resistance to rot, and tight grain.
Research led by the U.S. Forest Service Pacific Northwest Research Station found several interesting pieces of information related to yellow cedars including that low snow levels and poor soil drainage has caused impact root injury in the trees causing eventual death. Yellow cedars depend on wet soil and their shallow roots make it possible for the trees to obtain nitrogen. The survival of yellow cedars depends on changing snow patterns and thus, it is crucial that shifting snow patterns be evaluated when deciding which locations are suitable for the conservation and management of these trees in the future. Researchers also believe that yellow cedars may thrive in areas outside of where it has already migrated, leading to the hope that assisted migration may restore the dwindling population of these trees. However, there is also concern that assisted migration may cause yellow cedars to become an invasive species. Nevertheless, a trial planting of yellow cedars in Yakutat has been successful with a first-year survival rate of more than 90 percent.
The yellow cedar dilemma has also shed light on the impact climate change has on other species. Paul Schaberg, a plant pathologist for the U.S. Forest Service, sums it up nicely by stating, “as time goes on and climates change even more, other species, other locations, are likely to experience similar kinds of progressions, so you might do well to understand this one so you can address those future things.” Schaberg makes a valid point; in the future, there will be more plants and animal species whose habitats will be affected by climate change, and thus, more research and planning can aid in combating the loss of species such as the yellow cedar. To learn more about climate change and what you can do to help, please visit http://www.epa.gov/climatechange/.
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