Back in September the AZ Daily Sun's Bonnie Stevens posted an article titled Aspen Fading Fast on Sudden Aspen Decline, or SAD, which is a disease affecting quaking aspen groves around 7000 feet:
The soft sound of quaking aspen leaves trembling on the slightest breeze is the sound of summer in the mountains of the West. But that sound has become softer, and researchers believe the color of fall may be fading, too. This because of an extraordinarily rapid dieback of the aspen, a phenomenon biologists are calling SAD, or Sudden Aspen Decline.
In northern Arizona, Forest Service officials are reporting some 60 percent to 95 percent mortality in the low-elevation aspen groves, around 7,000 feet, of the Kaibab and Coconino national forests. Among the researchers diagnosing the sick trees is Northern Arizona University forestry graduate student Tom Zegler. "We are concerned because it's a tree that brings people into the woods. Its aesthetic values are high; it is one of the only trees in the West that turns colors in the fall. Aspen also have an extremely high ecological value. Per acre they provide for a greater diversity of wildlife than the sea of ponderosa pine trees around them. And because aspen allow more diffused light to reach the forest floor than other trees in northern Arizona, a greater diversity of understory plants can grow beneath them."
I hadn't heard of this condition before, but back when I was feeding the birds outside my apartment I noticed that many of the aspen trees in the complex were kind of sickly looking with many brown and blackened leaves and lots of wasps and aphid-like bugs crawling on them during the summer/fall. The ones in front of my place were positively horrid looking at times. The birds didn't seem to mind, though. When they weren't mobbing the feeder and pissing off my alcoholic neighbor the finches would spend their time poking around through all the leaves catching the wasps. For some reason I assumed the sick aspens were more a symptom of the sporadic watering and neglectful practices of the groundskeepers than something more widespread and endemic to the region.
Last weekend while I was up on Weatherford I saw some trees that clearly were not doing well and immediately remembered the AZ Daily Sun article on Sudden Aspen Decline (click for larger version):
Look how the leaves on these trees, none of which seem very old, are transitioning directly from the summer green to sickly brown and black, skipping the yellow color stage altogether. And it's the whole tree, not just a few branches. I suspect that this is exactly what the Sun article was talking about. In the same stand of trees there were others that were perfectly healthy looking with the foliage beginning to turn a nice golden yellow on the edges of each leaf. I hope this means that these healthier trees are fighting off the sickness and will return next year stronger than ever. Realistically it probably just means the sickness hasn't gotten to them yet...
Comments