YELLOWSTONE redwood souvenir (postcard?)

It's postcard sized anyway, roughly, and I *think* I've seen similar things marketed as souvenir postcards before -- but admittedly there aren't any signs of postage or postmark here. Just the imprinted YELLOWSTONE NATIONAL PARK markings on the back, with somebody's handwritten GREETINGS from [somebody], Eric, and Gertrude. Maybe with part of a date at upper right I can't make out all of either.

The front side is a relief scene of animals done by sandblasting the wood I believe, as it is soft redwood that'd be rather easy to do.