Oh yeah, I'm also working on a Douglas fir tree illustration for a watershed interpretive sign done by a colleague for the Bureau of Land Management (I think it's BLM, anyway). It will be in color, and has witches brooms on it (naw, ya can't fly with them, but they do sorta look like broom heads... They're caused by a parasite which makes the tree put out beau coup bristly twigs).
It's just a rough at this point, with a place left for an owl she already has artwork for near the top. The tree will fade off all along the length of the trunk, and there will be text and other spot illustrations to the right. The witches brooms are the two blobs near the center. Right now, it's gone to committee to make sure it fulfills everyone's expectations, so it might experience some changes. That's it at right.
OK, I'll be back later with updates.