"Emily M. Habinck, a former University of North Carolina graduate student, found that in places where the soil was relatively low in nitrogen and other essential elements, trees produced more red pigments known as anthocyanins. This finding supports a hypothesis by plant physiologist William Hoch of Montana State University, Bozeman, who argues that the increase in anthocyanin production in red-leafed plants, is the trees defense against fall sunlight. The additional protection allows the trees more time to gain valuable nutrients, offsetting the energetic cost of producing the pigment."