Good night, sweet trees
Sudden Aspen Decline is like a Shakespearean tragedy
June 25, 2009
In the pale predawn light, the branches of the aspens clawed at the sky as if trying to drag any moisture they could from the dry, cold air. The slow call of a mourning dove sounded in the distance as the first sun touched the uppermost branches. It was time to start my measurements. I grew up camping and hunting with my family across southwest Colorado, often in the dappled and dancing shade of aspen trees. Now I had returned to work on my doctoral dissertation. And one of my first research sites was here, in the very aspen stand that I had spent so much time exploring as a kid.
No one's childhood memories of a place survive returning to that place as an adult. Things seem to grow smaller, or dingier, with age, even if they haven't changed in reality. But here, the trees I remembered so clearly had changed. They were dead, all of them, their once leafy branches bare and skeletal. I had known they would be, of course. I had returned to Colorado after six years to study the mysterious, widespread aspen die-off, but I didn't foresee how visceral, how shocking it would be.
Sudden Aspen Decline, as researchers call it, has hit this part of the Rocky Mountains hard. Nearly 20 percent of the aspen trees have died over a four-year period. Along with several other researchers from Stanford University, I spent the summer camping in the forests I grew up in, trying to figure out why. I did my work with cold detachment, with a jumble of scientific instruments, but I mourned inside.
August 5, 2009
I straightened my tie with trembling hands and glanced out at the crowd assembled at my hometown's Cultural Center. Abruptly, I understood the trepidation that most scientists feel giving public lectures. Worse yet, I had put climate change in the talk's title and, though confident about the science, I was nervous about discussing it here. Cortez is a mid-sized farming town in a rural, deeply conservative county.
I should have served wine beforehand, I thought to myself as I welcomed everyone and put up the first slides. Better yet, whiskey. But I launched into my talk anyway: How many people had noticed the dead aspens on their land or near the road in the mountains? All hands went up. Who remembered the mass death of the pinon pine forests across the Four Corners states several years ago? All hands went up again. Across the Southwest, hundreds of thousands of acres of pinon pine had rapidly succumbed to a beetle in just a few years. Scientists found that the severe 2002 and 2003 droughts lasted no longer than those of the Dust Bowl or in the 1950s, but they differed in one very important respect: They were hotter, most likely due to manmade climate change. Our current scientific picture of the recent half-million-acre aspen die-off paints an incomplete picture, but all lines of evidence to date point towards a similar one-two punch of drought and global warming as the primary cause. When I said this, I expected grumbling, if not a roar of disagreement.
But the protests never came. These people had seen the dead forests all around them. The pinon pine die-off had left huge swaths of the landscape a sickly brownish-red. Then the massive lodgepole pine scourge swept across Colorado's high-altitude forests, and continues to wreak havoc today. Faced with mounting evidence on a very concrete level, the locals have come to understand that Western forests are already in trouble, and climate change is the most likely culprit. This audience asked the same question locals had asked all summer -- What can we do about it?
August 10, 2009
The hot Colorado sun baked the dead aspen forest. There were none of the cotton-candy cumulus clouds that normally bring afternoon monsoons. My T-shirt grew damp and clung to my body. I leaned over and plunged the shovel into the soil again and again, turning over sections of rich black dirt. Pausing to sift through the drying clods, I sighed in frustration and kept on digging.
I was looking for young aspens and, more importantly, for the root networks in the soil that support them. When I finally found a root, I held it up to the sun. Like almost all of the others I'd found, it was brown, rotten and already dead. The empty canopy above me signaled the death of a stand of trees, but the surprising lack of re-growth and living root network in afflicted forests spelled an even darker future for whole forests of aspens. Turning the dead root over in my fingers, I pondered the mysteries that still shroud this die-off. Aspen root networks are thought to stay alive in the soil for hundreds or even thousands of years and have never before been observed dying en masse. The root death seems to accompany the canopy death across nearly a fifth of Colorado's aspen forests. It brought to mind what my mother said, on seeing the pollution from two nearby coal power plants that sometimes covers our corner of Colorado: We live in interesting times.
August 20, 2009
Returning to my hometown high school was like going back to my childhood camping spot: a mix of warmth and apprehension. I had failed to find budding aspens in the forest, but here I hoped to engage budding minds about the local forests, science and going to college. The biology classroom was packed with students and teachers, eagerly awaiting a presentation by my brother and me.
After my brother explained to the students why they should attend college and study science, I put up our most stunning pictures of aspen research. Examining the roots may be dirty, sweaty work, but studying the canopy can be spectacular. In one video, I ascend an aspen swaying wildly in the wind of an oncoming storm to recover a piece of scientific equipment that resembles a robot from The Matrix. After I told the story of aspen decline, explained the science of climate change, and detailed how severely it is expected to impact the West, we made an offer: Interested students could join our research crew the following summer. Hands went up, even among the teachers. This group would add to the 14 middle school and high school students from northern New Mexico who had already pledged to join us. Looking out over the classroom, I felt a brief surge of an emotion that had been absent all summer -- hope.
August 31, 2009
Flecks of yellow speckled the still-living aspen canopy in front of our final field research camp as the sun set. I took my final pictures and conducted my last measurements of the season, then sat down on the drying grass to read a few more passages of Shakespeare's Hamlet, which had been my summer reading.
I had come to realize that the story of the aspens is a Shakespearean tragedy still unfolding. The fate of the protagonist has not yet been written in stone, the trees are buffeted by forces beyond their control, and a combination of their own traits and the corruption of society will bring about their downfall. Early projections indicate that between 50 to 90 percent of aspen forests may disappear by the end of the century.
The most heartbreaking part of a Shakespearean tragedy is the fact that we know what's coming. Ultimately, this will be the story of climate change. Whether it's the loss of the world's coral reefs, drought-induced crop failure, or the death of entire forests, the story of the aspens will not be unique. Perhaps we can learn from this tree, a hallmark of our Western landscape, before it's too late.
In the still evening air filled with the soft calls of swallows and thrushes, I walked away from camp and into the aspen grove across the meadow. I ran my fingers across the dusty white bark and looked up at the trembling kaleidoscope above me. The wind whispered in the leaves and the crickets whirred. Like Horatio, I wanted to do something –– to warn Hamlet, to stave off the end of the tragedy. But I was the only one in the grove who knew the trees' time was running out, and how close we were coming to the end of the play.
William Anderegg grew up hiking, fishing and hunting throughout southwestern Colorado. He is currently a doctoral candidate at Stanford University, studying aspen decline and the impacts of climate change on ecosystems, and in his free time he writes fantasy novels.