Why are my trees turning pale?

I'm using the tree creator, and I have 4 trees with textures and materials. Over time, as I worked on my scene (I was working on shadows, terrain textures and sun flares)... I began to notice my trees were starting to turn pale. The paleness seems to be in the materials and textures that are attached to the trees. If I navigate the editor to the texture file, I see it looks pale too. This paleness began gradually and increased over time. How do I fix it? I'm using no scripts except: Unity 4, Relief Terrain Pack v3, and Terrain Composer.