Mark Brooks, a designer from New York, uses nature as the basis for most of his work. In fact, most all of his works have an earthy feel. He establishes this using color and shape combined with subtle hue, saturation and value. His works are usually made with the intentions to trigger a specific emotion. Also, many of his works were created for readings in “organic poetry.” Organic poetry is a genre of poetry that describes and praises nature in all of its forms.
Here is a link to his work: http://www.markbrooksgraphikdesign.com