Pando is the largest living thing on earth. Weighing 6,000,000 kilograms, it is about as heavy as a thousand African elephants or forty blue whales. When you enter Pando, you may hear a soothing sound like the beating of tiny wings. Pando is a grove of 47,000 quaking aspen trees, named for the distinct sound their leaves make in the wind. Every tree in the forest is genetically identical. This is because they are all parts of a single being, connected underground by a huge root system. We cannot be sure of Pando’s age, but based on its rate of expansion, coupled with a knowledge of historic climatic conditions, it could be up to 80,000 years old. If Pando is this old, it is not only the largest known organism on earth but also the oldest. In a painfully familiar twist, humans pose a serious threat to this gentle giant.
Pando’s namesake derives from the Latin for ‘I spread’ as Pando started life as one seed, then gradually spread itself out over an incredible 106 acres of Utah, an area equivalent to 1,700 tennis courts. Aspen spread through a process called vegetative reproduction. They send out roots underground which travels horizontally for as much as a hundred feet before sprouting into new trees. The roots then carry water and nutrients to the new sprout as needed. One reason why aspen clones like Pando can get so big is that aspen is remarkably quick to repopulate an area following a major destructive event like a forest fire. Aspen competes with conifers for light and nutrients, a competition they may well lose without the help of forest fires. Unfortunately for aspen, humans tend to put out fires wherever we can, leaving conifers to creep into the aspen’s territory. This is just one of the ways in which we are harming Pando.
For the last hundred years or so, humans have been hunting predators like wolves, bears and mountain lions in Utah and the surrounding area, leading to an increase in ungulate (hoofed mammal) populations. The main culprits are a species known as mule-deer, who eat young aspen trees before they have time to grow a thick bark with which to protect themselves. Not only does a decline in predator populations mean that fewer mule deer are being eaten, but it also means that they have become more likely to stick around and enjoy the good eating. With no predators to chase them away, the deer see no reason to move on and find a new feeding spot.
It does not help that the US forest service allows ranchers to graze their cattle on Pando for two weeks every year. Aerial photographs taken over the last fifty years show that Pando is in serious trouble. Given such data, it is extremely irresponsible for the forest service to allow any grazing at all. You may well be wondering at this point why I’m telling you all this. Pando is not like other organisms. While it is a single being, Pando is also a vast ecosystem which is home to a huge variety of animals from black bears to wild turkeys. By saving Pando, we are saving not only a biological marvel but also a forest and everything that lives within it.
A healthy aspen grove should have trees of all ages growing within it. As in a human community, it is far from ideal for the individual trees to all be the same age. If everyone in a town is over 80, there will be no youngsters to replace them when they’re gone, and the town will die with them. This is exactly what is happening to Pando’s trees. The director of the Western Aspen Alliance and Pando expert Paul Rogers has said that in many areas there are “no young or middle-aged trees at all” and that the trees that remain are “very elderly senior citizens”. Aspen trees can live anywhere from around 75-150 years old. Worryingly, the average age of trees in Pando is 130 years; if we are to save it, we are going to have to move very fast indeed.
So what can be done to save Pando? Paul Rogers recently conducted an experiment in which parts of Pando were fenced off to stop ungulates from getting in. The experiment showed very promising results, although, despite the fences being 8 feet tall, the deer were somehow able to jump over them in some places and damage the new shoots. Some have suggested that to save Pando, wolves need to be reintroduced into the ecosystem to kill the deer. The proximity of Pando to campsites and cottages makes this idea hard to sell. The evidence suggests that taller fences around larger sections of the grove and a ban on all grazing should allow new trees to flourish. Once a new generation of trees come up and live to maturity, Pando will be in a strong position to live on for years to come. However, it will also face the very real threat of global warming if we do not significantly reduce our emissions soon.
Pando is emblematic of the large scale ecological and climatic devastation that humans have wrought on this planet. By altering certain variables, we may have sealed Pando’s fate without even knowing it was there. It is important that knock-on effects like these are understood so that we may avoid repeating the same mistakes. Pando is also a symbol of how, with a bit of elbow grease and a bit less greed, we can at least partially right many of the wrongs that we have done to the natural world. When you are responsible for a problem, it is your responsibility to fix it. We can save Pando. Maybe by joining together to preserve this one beautiful colossus, we can create a success story that can serve as a poster-child for conservation efforts around the globe.
By Adam Boland – Science Writer