Reaching heights of over 100 meters, Californian sequoias tower over Earth's other 60,000 tree species. But even these behemoths seem to have their limits: no sequoia on record has been able to grow taller than 130 meters. So what exactly is stopping these trees from growing taller, forever? Valentin Hammoudi investigates why trees have limited heights. [Directed by Doug Alberts, narrated by Addison Anderson, music by Doug Alberts].