Mexican bark paintings are made from a thin bark (I don't know which tree), and the paint appears to be similar to watercolors. They usually depict tropical birds or scenes, so I am guessing the artists are native to Chiapas state or another tropical location in Mexico.

mexcan bark painting example

This is typical of the art form. I mounted the painting behind plexiglass to protect them. I used to just hang them, but they are quite fragile.

These paintings are 24 inches by 16 inches.

another mexican bark painting

I think both these paintings are of birds of paradise, but they are very stylistic, so it is hard to tell.