One More Bridge and More Forest

Backstory: I didn't realize it until finished but the last bridge I built was for a wider river section...did you hear this story already? No matter.  I bought a nice truss bridge from GHQ, but it's for a much narrower river. So, I set forth building my own. I made a template in a drawing program that was a lengthened version of the GHQ bridge. I was going to be ambitious and make it out of styrene strips. After much cursing and superglue everywhere but where it was supposed to be,  I said fiddle it, glued the template onto thin cardboard, and carefully cut it out with an Xacto knife. I glued glued styrene strips to the top and bottom and declared it done. Here it is so far:

Good enough for government work. I'll post another picture when it's all done.

Onto forests. I made my next big forest using the same technique but this time with  1" roofing nails for trunks. Its the bigger of the two in the box:

Box O Trees

I slathered the nails with caulk and the points stick into the ground to try to make them less obvious.  To me, they turned out ok, but a little thicker than I wanted. I suppose I could try thinner nails, but I might as well use the dowels.

Something that I noticed that bothers me is that the flocking of some of my trees have turned a sickly pale much like what happens to  broccoli when you leave it in the refrigerator too long. My models and terrain stuff are stored by a window, but these trees are in boxes and I have a bunch of trees for my 15mm games that are totally exposed to the light and show no discoloration, so it can't be due to UV light. I am not sure why this happened.  Any thoughts?