The bark-skinned Trevis
Bark was the external layer of a tree.
In 2267, Spock appreciated the tensile cohesion of bark used to make a bowstring. (TOS: "Friday's Child")
Trevis, Neelix, and Naomi Wildman all made "silly puns" about the tree character; twice about his bark being worse than his bite, and once about getting hot under the bark (aka collar). (VOY: "Once Upon a Time")