Dragon Skin lichen is a large-leafed lichen that resembles a piece of lettuce.  It is found on trees in the mid-canopy, where it is well-shaded, cool, and moist.  Dragon-skin lichen is incredibly sensitive to light exposure and primarily grows in old-growth forests because it needs an environment that has an uneven canopy caused by multi-aged trees. This lichen fixes nitrogen, changing atmospheric nitrogen (N2), which a plant is not able to consume, to ammonium (NH4), which the plant can consume.  The nitrogen that is fixed by this lichen ultimately ends up on the forest floor via leeching from rain and the decomposition of fallen lichen. Lichens that fall to the forest floor also play an important role in supplying deer, elk, and small mammals with winter food.