Scientific American: Swedish Spruce Is World's Oldest Tree

What's sixteen feet tall and 9,550 years old? It’s the world's oldest tree. The worn and weathered spruce grows in Sweden's windswept tundra. But, until recently, well, recent to the tree at least, it barely resembled a tree at all. Before this last warm century, the spruce grew more like a shrub to survive the harsh conditions of its cold landscape. But rising temperatures convinced the tree to give up its shabby lifestyle, shed the majority of its needles and go with the single-trunk look.
Scientific American: Swedish Spruce Is World's Oldest Tree