Giant sequoias are unimpressed by your puny human lifespan. Between the years 800 and 1300, while Europe was still slogging its way through the dark ages, the California sequoias were enduring a dry shift in the climate that sparked more wildfires. We know because sequoias still alive today bear the fire scars. The marks in their tree rings match up with charcoal deposits in the area that date to the same period, too.