Alder

Alder is an English nature name taken directly from the tree. It can also occur as a surname, so a particular family's reason for using it may be genealogical rather than botanical. The tree provides a clear explanation without needing to turn speculative older roots into a separate meaning such as “old” for every bearer.

Its ending resembles surname names such as Carter and Parker, while its plant connection places it alongside Rowan and Willow. Alden is close in sound but has a different naming history. Al can serve as an informal shortening. Keeping Alder in full preserves the tree reference, which may be especially useful when the natural-world connection is the reason for choosing it.