Cicadas overwhelm tree branches across the Mid-Atlantic once every 17 years, like clockwork. But something — some suspect it’s climate change — could be sounding their alarm clocks four years early. In
This looks like a forest, but it's actually just one tree — and it's one of the oldest and largest organisms on Earth
But not all trees follow that formula. Some form what are called clonal groves: swaths of forest connected underground by a single network of roots, with each trunk genetically identical to the others.