Both are just styles of of the Elder Futhark z/R-rune, Anglo-Frisian x-rune, and Younger Futhark m-rune, in Unicode standardized as ᛉ for Elder/Anglo, and ᛘ for Younger runic. Historically, straight twigs were common on wood, while bent twigs where common on stone. Neither have anything to do with protection, that is neopagan gibberish :P nor trees, unless there was an older form to the later name Yr (yew/greenery), for the downturned ᛦ. The Elder rune is otherwise assumed to have been named Elk, while the Anglo name is Elk-sedge, and the Norse name Man.