38 degs. and you were cold? Couple of things....boughs let cold air under you. I've NEVER been able to keep warm using tree limbs. Dried leaves and hay/grass work well if you use a large volume of the stuff, but boughs make great summer sleeping, because it ventilates.
A foam pad or two would have kept you off the snow and trapped warm air. HAT! Big loose knit or fleece hat will keep you amazingly warm. Rag wool mittens (or socks) for your hands and some more socks for you feet. Plastic bags for the feet in a pinch.
My last hammock camp was 4 weeks ago in 27 deg. I was toasty with a 1/2 Ridgerest pad, hat, gloves, socks, thin wool long johns. I use my jacket (down) to cover my feet or block off cold spots. Most of us here use down bags as do I.

Anyway, thanks for posting your report and pictures!
Interesting stuff.