Native Americans were decimated by diseases, such as smallpox, introduced by the European colonists. The American Chestnut has been all but eradicated by a fungus inadvertently brought into North America on Asian nursery stock around 1900. And now a fungus is killing off oaks and other trees in California, with probably over 100,000 oak trees already dead. Another import? Or a native son now able to attack trees weakened by pollution or other adverse conditions? Or possibly a formerly insignificant pathogen with a new mutation suddenly increasing its virulence?
Basically, we don't know. First recognized in California in 1995,
it now is sweeping the oak forests of California. Even more worrisome, it's
spreading into other kinds of trees, including Redwoods. Some kinds of plants grown by
nurseries also are infected, leading to fears of spread through the nursery trade.
Laboratory studies indicate that Eastern species of oaks are susceptible, fueling fears
of a repeat of the American Chestnut's demise. Loss of even a few species of oaks
from the Eastern deciduous forest would change the vegetational landscape
forever.
Contributor: Arthur H. Harris, Laboratory for Environmental Biology, Centennial Museum, University of Texas at El Paso.
Desert Diary is a joint production of the Centennial Museum and KTEP National Public Radio at the University of Texas at El Paso.