Why are tree trunks brown?

Trunks are brown because bark is brown. Bark is the tree’s tough coat. It feels rough under your hand. It helps keep the tree safe.

Tree trunks look brown mostly because they are covered in bark. Bark is the tree’s hard outer coat. It has natural brown colors in it, and the outside can get dry and dark. It helps protect the tree, like your coat helps protect you from wind and rain.

A trunk looks brown because its outside layer is bark. Bark is made of tough, dry cells, and it contains natural colors such as tannins, which often look brown. This rough layer helps guard the living tree inside from sun, cold, bugs, and scrapes. Fun fact: not all trunks are brown. Birch trees can look white, and the rainbow eucalyptus has bark with green, orange, and purple patches.