In the Wasatch Mountains of the western United States on the slopes above a spring-fed lake, lives a single giant organism that provides an entire ecosystem that plants and animals have relied on for thousands of years. Located in my home state of Utah, “Pando” is a 106-acre stand of shaky aspen clones.
Although it resembles a wooded area of individual trees with striking white bark and small leaves fluttering in the slightest breeze, Pando (Latin for “I spread”) is actually 47,000 genetically identical stems arising from an interconnected root system.
This single genetic individual weighs about 6,000 tons. Measured in mass, it is the largest single organism on Earth.
Aspen trees tend to form clonal stands elsewhere, but what makes Pando interesting is its enormous size. Most clonal aspen stands in North America are much smaller, with those in the western United States averaging only three acres.
Pando has been around for thousands of years, potentially up to 14,000 years, despite the fact that most stems have only lived for about 130 years. Its longevity and remote location mean an entire ecosystem of 68 plant species, and many animals have evolved and been supported under its shade.
This whole ecosystem depends on the aspen remaining healthy and upright. But even though Pando is protected by the US National Forest Service and is not in danger of being felled, it is in danger of disappearing due to several other factors.
Deer eat the youngest ‘trees’
Overgrazing of deer and elk is one of the biggest concerns. Wolves and cougars once kept their numbers in check, but the herds are now much larger due to the loss of these predators. Deer and elk also tend to congregate in Pando, as the protection the forest receives means they are not in danger of being hunted there.
As older trees fall down, the light reaches the forest floor, stimulating new clonal stems to start growing, but when these animals eat the top of newly formed stems, they basically kill baby trees. This means that in large parts of Pando there is some new growth.
The exception is an area that was fenced in a few decades ago to remove dying trees. This fenced area has excluded moose and deer and has seen successful regeneration of new clonal stems, with dense growth referred to as the “bamboo garden”.
Pando: Diseases and climate change
Older stems in Pando are also affected by at least three diseases: sooty bark cancer, leaf spot and conch fungal disease.
While plant diseases have evolved and thrived in aspen stands for millennia, it is unknown what the long-term effect on the ecosystem may be, given that there is a lack of new growth and an ever-growing list of other pressures on the clone giant.
The fastest growing threat is climate change. Pando emerged after the last ice age had passed and has ever since dealt with a largely stable climate. Admittedly, it lives in an alpine region surrounded by desert, which means it is no stranger to hot temperatures or drought. But climate change threatens the size and longevity of the tree, as well as the entire ecosystem it hosts.
Although no scientific studies have focused specifically on Pando, aspen stands have struggled with climate change-related pressures, such as reduced water supply and warmer weather earlier in the year, making it harder for trees to form new leaves, which has led to declines. in coverage.
With more competition for ever-shrinking water resources (the nearby fishing lake is just out of reach of the tree’s root system), temperatures expected to continue to rise to record highs in the summer, and the threat of more intense forest fires, Pando will certainly struggle to adapt these rapidly changing conditions while maintaining its size.
Pando: The next 14,000 years
Yet Pando is resilient and has already survived rapid environmental change, especially when European settlers began inhabiting the area in the 19th century or after the rise of 20th century recreational activities. It has dealt with diseases, wildfires and grazing before and remains the world’s largest scientifically proven organism.
Despite every cause for concern, there is hope as scientists help us unlock the secrets behind Pando’s resilience, while conservation groups and the US Forest Service work to protect this tree and its associated ecosystem. And a new group called Friends of Pando aims to make the tree accessible to just about everyone through 360 video footage.
Last summer, while visiting my family in Utah, I took the opportunity to visit Pando. I spent two amazing days walking under towering mature stems that swayed and “trembled” in the gentle breeze, between the thick new growth of the “bamboo garden” and even into charming meadows that puncture parts of the otherwise closed center.
I marveled at the wild flowers and other plants that thrived under the spotted shade crown, and I was able to rejoice in seeing pollinating insects, birds, foxes, beavers and deer, all using part of the ecosystem created by Pando.
It is these moments that remind us that we have plants, animals and ecosystems that are worth protecting. In Pando, we get the rare chance to protect all three.
This article was originally published on The Conversation by Richard Elton Walton at Newcastle University. Read the original article here.
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