Depending on the weather, a tree can certainly be used as shelter. If it is a hot day and you'd like to escape the sun, you can take refuge under a tree. However, it is raining and there is lightning, it is not advisable that you take shelter under a tree as the tree might attract lightning.
to keep them cool
A lemur typically uses either a bush or a tree for shelter. They also use bushes and trees in order to hide from their predators.
Animals use the river birch tree for food, shelter, and nesting. Squirrels and birds feed on its seeds and insects attracted to the tree. Woodpeckers may also excavate nest cavities in the tree's trunk.
a vulture lives in a nest in a big huge tree . the shelter is the tree
The Gum Tree provides shelter for Koala's and Many Animals use it to keep in the shade when it is hot
To help their shelter and make stronger
Margays like to shelter in the hollow of a tree.
Kingfishers shelter in there nest and in a bush/tree
A toucan lives in a tree.
monkeys sometimes use tree leaves to make shelter or other times they might use big boulders or rocks. they also might hide in trees.
the metis use tree and bark and mud my friend is falf metis
tree branches are the shelter of wild monkeys.