Aspen Trees Rake Clouds from the Sky

In the early years of this century people in the Rocky Mountains of Arizona, Colorado, and Utah began to notice that aspen trees were dying-off wholesale.  Surveys in some lower elevation forests revealed a loss of 90% of the aspen trees between the years of 2000 and 2007.  Alarmed by the loss of the trees—some of which have formed huge groups or “clones” of genetically identical trees—foresters began to investigate what is now called SAD (sudden aspen decline).  SAD has afflicted clones that cover many dozens of acres and have thrived for thousands of years.  These clones are considered the largest organisms on the planet.

Following intensive research, foresters determined that SAD is the result of hydraulic failure.  Essentially, the aspen are developing embolisms (the quaking aspen equivalent of a blood clot) in the internal vessels that carry water up from the roots to the branches and whispering leaves.  The hydraulic failure is the result of stress attributed to the severe drought which afflicted the American West at the same time that people began to notice aspen decline.  If the predictive weather and moisture models for the West hold true, severe drought may become the new normal.  Aspens will die.

Climate change?

Maybe so.

Yesterday, Ariel Murphy and I drove up into the snowbound Alice Creek drainage to visit her favorite aspen grove.  The trees are very much alive, though wintering.  We stood amid bluish snow drifts and watched them rake clouds from the sky for a while.  Before we left, I stepped into the clone and took a picture of a patch of blue sky islanded in the flow of clouds above.

--Mitchell Hegman