The rings of a Bristlecone Pine can be read like a book. Rings taken from a coring of Methuselah indicated that something occurred in 1627 B.C.E. For some reason, ring growth during that summer was prematurely halted. The ring showed damage from freezing. Further investigation revealed that 3,629 years ago, the volcano Santorini which made up the island of Thera in the Agean Sea erupted. The eruption, which was much greater than the Krakatoa eruption of 1883, led to the destruction the Minoan civilization and caused a mini-ice age dropping world-wide temperatures for nearly a decade.

Pretty much the only thing that can kill one of these Ancients is a direct lightning strike...Or man.