While white protects bark, other colors and patterns indicate instructions for people. For example, some trees bear marks to show that they are diseased, must be chopped down, or require pruning.

No discussion of beautiful-barked trees would be complete without mention of the lemon-scented gum (Eucalyptus citriodora). The alabaster bark of this beauty gives it a unique presence.

Madayin: Eight Decades of Aboriginal Bark Paintings is the new exhibition at the Asia Society in Manhattan, on Park Avenue and 70th Street.

Bark textures are relatively uniform by tree species and make a great visual marker for broad tree identification. Textures are divided into at least 18 types, from smooth (beech) to spiny (locust).