Photos courtesy of Chad Oukrop, USU
The question of what's killing the Aspen trees brought together dozens of experts in Logan this week. They're sorting through significant Aspen die-offs. It may be part of a much larger and very worrisome trend.
The immediate concern is something they're calling "Sudden Aspen Decline". But trees of many species are dying in record numbers, and the trend is getting worse. It's an issue of increasing concern, not just in remote mountain areas, but in places where we live and appreciate the shade.
Photos show something that's alarming people near Cedar City. Reports of similar problems have been coming in from around the Four Corners.
Dr. Paul Rogers, director of the Western Aspen Alliance, said, "Dying off of mature aspen trees in the area, and in some instances no regeneration coming up underneath that."
The concern is serious enough that dozens of experts from the U.S. and Canada met at Utah State to assess how widespread the die-offs are for a tree species beloved by many.
"I don't think they should worry about losing it across the range. What we're worried about right now is in specific areas," Rogers said.
If there is a crisis for aspens, this species is not alone. Similar threats seem to be killing trees throughout the west. In mountain areas drought is weakening trees, allowing beetles to move in for the kill. As the globe warms up, beetles are moving further north and to higher elevations, attacking trees on a scale that hasn't happened in thousands of years.
Jesse Logan, a beetle researcher, said, "Massive outbreaks occurring, continent-scale. Unprecedented within the European history for sure, and probably much longer than that."
Drought is taking a toll in Salt Lake City too. Since 1990, tree removals have risen from 500 a year to 800. It's partly because trees are aging but also because we're supposed to "Slow the Flow" and save water.
Bill Rutherford, a Salt Lake City urban forester, said, "It's an important message, and people are taking it to heart because we live in a dry state. But one of the unintended consequences is trees are not getting the amount of water that they need."
Global warming studies provide a mixed forecast. Dr. Robert Gillies, the director of the Utah Climate Center, said, "That the southern part of the state is becoming dryer, and that the northern part of the state will become wetter." But hotter temperatures will likely evaporate away the extra moisture in the north. "And that ends up being a net deficit," Gillies said.
All of this suggests we'll be worrying about trees for a long time. One of the ironies of the situation is that trees can be part of the solution to global warming. They provide cooling shade and recycle carbon dioxide, but they aren't going to help us much if they don't get enough water.