Pando, tree clone of the Wasatch mountains, UtahInga Spence/Visuals Unlimited/GettyBy Emily BensonMeet Pando, thought to be the world’s largest living thing by mass. It’s a forest, but all of its 47,000 trees come from a single root system spread over 43 hectares in Utah, making it genetically one individual. But Pando is dying. Hungry deer and cattle...