Land & Environment

First Comprehensive Assessment of Pando Aspen Clone Reveals Critical Threats

By Traci Hillyard |

The Pando aspen clone as scene from a distance (green foreground and middle - not yellow). The photo captures about ½ the total grove. A close look reveals many dead trees on the ground. Foreground depicts successful regeneration; middle green shows dying forest with little new growth. (Credit: Lance Oditt, Studio 47.60° North – with permission).

Utah State University researchers Paul Rogers and Darren McAvoy have conducted the first complete assessment of the Pando aspen clone and the results show continuing deterioration of this ‘forest of one tree.’  While a portion of the famed grove is recovery nicely as a result of previous restoration, the majority of Pando (Latin for “I Spread”) is diminishing by attrition.

Rogers and McAvoy, in a PLOS ONE publication released Oct. 17, show Pando, Utah’s massive, yet imperiled, aspen clone, is in grave need of forest triage.  Early protection from fencing showed great promise in abating browser impacts, which have nearly eliminated recruitment of young aspen stems for decades now. However, follow-up fencing of a larger area (in combination with about half of Pando remaining unprotected by fencing) is currently failing according to this study.  

“After significant investment in protecting the iconic Pando clone, we were disappointed in this result,” says Rogers, director of the Western Aspen Alliance and Adjunct Faculty member in USU’s Wildland Resources Department. “In particular, mule deer appear to be finding ways to enter through weak points in the fence or by jumping over the eight-foot barrier. While Pando has likely existed for thousands of years—we have no method of firmly fixing its’ age—it is now collapsing on our watch.  One clear lesson emerges here: we cannot independently manage wildlife and forests.”

The complete study is available via the open access journal PLOS ONE here: http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0203619.

In addition to presenting the first comprehensive analysis of forest conditions, the study offers a unique 72-year historical aerial photo sequence the visually chronicles the a steady thinning of the forest, past clear-cuts that remain deforested today, and continual intrusion of human development.  Taken as a whole, objective analysis and the subjective photo chronology reveal a modern tragedy: the “trembling giant” that has lasted millennia may not survive a half-century of human meddling.

Pando is widely considered the world’s largest single organism weighing in at an estimated 13 million lbs. (5.9 million kg). Covering some 106 acres (43 ha) in south-central Utah’s Fishlake National Forest, the clonal colony consists of more than 47,000 genetically identical above-ground stems or “ramets” originating from a single underground parent clone.  Quaking aspen, Pando’s iconic species, was named Utah’s State Tree in 2014 and, among numerous values, is considered a staple of scenic montane landscapes in the American West.  Rogers sees trends found at Pando occurring across the western states, thus the Western Aspen Alliance serves as a clearinghouse of contemporary aspen sciences for professionals, scientists, and policymakers.

“In addition to ecological values, Pando serves as a symbol of nature-human connectedness and a harbinger of broader species losses,” Rogers says. “Here, regionally, and indeed internationally, aspen forests support great biodiversity. This work further argues for ‘mega-conservation’ as a departure from traditional individual species-habitat approaches. It would be shame to witness the significant reduction of this iconic forest when reversing this decline is realizable, should we demonstrate the will to do so.” 
 

A seventy-two year aerial photo chronosequence showing forest cover change within the Pando aspen clone, Utah, USA. Photos were georectified using ArcMap® software to ensure accurate scale and location alignment. Yellow polygon depicts the boundary of the 43 ha clone as projected over each photo year. (Credit: Base images courtesy of USDA Aerial Photography Field Office, Salt Lake City, Utah.)

Pando Grove in fall foliage at Dr. Creek Campground, Utah (Credit: Paul C. Rogers)

Mule deer inside the Pando aspen clone near Fish Lake, Utah. Mule deer chronically browse off young aspen stems leading to total loss of "next generation" forests. This forest, made up almost entirely of old trees, has a bleak future without integrated forest-wildlife management. (Credit: Paul C. Rogers)

WRITER

Traci Hillyard
Public Information Officer
S. J. Jessie E. Quinney College of Natural Resources
435-797-2452
traci.hillyard@usu.edu

CONTACT

Paul Rogers
Director
Western Aspen Alliance
435-797-0194
p.rogers@usu.edu


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TOPICS

Research 545stories Ecology 138stories Genetics 56stories Conservation 44stories Restoration 30stories

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