arboreal
Living in trees or related to trees and treetops.
Arboreal means living in trees or relating to trees. An arboreal animal spends most of its life up in the branches rather than on the ground. Monkeys are arboreal creatures: they swing from branch to branch, sleep in treetops, and find their food among the leaves and bark. Squirrels, tree frogs, and many birds are arboreal too.
When scientists describe an animal as arboreal, they're telling you something important about how it lives: it has special adaptations for tree life, like strong gripping hands, long tails for balance, or the ability to climb and jump between branches.
You can also use arboreal to describe things that simply relate to trees, like the arboreal beauty of a forest or an arboreal habitat. If you love climbing trees yourself, you might joke that you have arboreal tendencies: you feel most at home when you're perched on a sturdy branch, looking down at the world below.