We all know that trees are essential for the environment, but trees are actually quite important to visual artists as well.
While the finest papers are still made from rags, these days, most paper comes from wood pulp.
Paper also is processed and sized with various gums derived from trees.
Rosins, usually from pine trees, are used as surface coatings for many papers.
Many historical works of art - especially Italian paintings - were created by dissolving pigments in walnut oil.
Gums from trees act as binders for watercolors.