Scientists are currently embroiled in a debate about whether trees have the potential to be immortal or not. Countering the optimism of a study published earlier this year that conducted genetic analysis of robust 600-year-old ginkos, biologist Sergi Munné-Bosch argues there are limits to the regeneration of plant physiology. He also underscores a temporal conundrum: how do scientists that measure their lifespan in decades rigorously study subjects that can live for centuries and even millenia?