There's a simple answer: Sequoia and Sequoya are different words -- homophones -- that are misleadingly pronounced the same. As Ms. Wis./Each Little World noted in reply, sequoia is the name of a tree, better known as the Coast Redwood or California Redwood.
Green as it is with its greywater collection system, Sequoya is not named after a tree. It's named after the great Cherokee leader Sequoya who gave his people the tools for literacy.
Sequoyah (ᏍᏏᏉᏯ Ssiquoya, as he signed his name, or ᏎᏉᏯ Se-quo-ya, as his name is often spelled today in Cherokee) (circa 1767–1843), named in English George Gist or Guess, was a Cherokee silversmith who in 1821 completed his independent creation of a Cherokee syllabary, making reading and writing in Cherokee possible. This was only time in recorded history that a member of an illiterate people independently created an effective writing system. After seeing its worth, the Cherokee Nation rapidly began to use his syllabary and officially adopted it in 1825. Their literacy rate rapidly surpassed that of surrounding European-American settlers.Can't think of a better name for a library.