Tree conks, nature's canvas, are a type of fungus known as the shelf mushroom. They are most frequently found on dying hardwood trees in the Northeast but can be found all over the country. Although some care must be take while collecting them (to ensure the milky white flesh isn't damaged), they dry to a white color and almost woodlike hardness, which makes them suitable for painting. Their three-dimensional quality also makes them perfect for when you want a free-standing piece or to create a painting that is viewable from every angle.
Prepare the conk by allowing it to dry completely for several months. If you collect the conk yourself, you can prepare it by scoring the white meat of the fungus. This will dry to a sort of light brown or sepia color and become as hard as wood, so you can paint over or around it later if you wish. You can also buy conks dried, so you may skip this step.
Apply gesso to the parts of the conk you wish to paint. The gesso is most helpful if you have a conk with damaged meat (it will be brown or sepia colored instead of white) or want to paint in light colors on the entire conk, not just the flesh.
Draw your design onto the conk after the gesso has dried.
Paint the conk as you would any other painting but use only acrylic and oil paints (or spray paint) and allow it to dry. Water colors will not work well on a conk.
Apply a coat or two of lacquer to your conk. Cats particularly love the smell of conks, so by sealing it you are sealing in the scent as well as protecting your art. Don't forget to turn it over and seal the bottom after the top has dried.