Like his brother Dolveros, Dolvethir was born at the end of the Second Age, after the captivity of Sauron but before the fall of Númenor. His father was a Nandor of Ossiriand and his mother an elf of the Falas who settled in Lindon at the end of the First Age. His father perished in the War of the Last Alliance. Having seen both her sons grown to maturity, His mother has recently taken ship to Eldamar to be reunited with her husband when he returns from the Halls of Mandos.

Dolvethir has largely dwelt in the forests of eastern Lindon, between the Lune and the Blue Mountains, where he has pursued a simple but rich life as a forester, hunter and protector of the borders. Even when he has passed west of the mountains, he has kept to the woodlands and has not seen the sea, knowing he would be torn between his love of the forests of Middle Earth and the call to the True West.

Dolvethir is descended on his father's side from the Nandorin lord, Lenwë through Daintáro (in Sindarin, Denethor) who first brought the silvan folk into Beleriand. While this high lineage shows in face and form, he holds no special status even as a leader amongs the elves who range the woodlands.

"Tenderleaf" is the Westron rendering of his byname, Nethenlas, denoting a new leaf of Spring in recognition of his seeming youth in spite of his years.