https://www.atlasobscura.com/articles/forest-service-signs-history
Virgil "Bus" Carrell was the guy behind all the Forest Service signs all across the country - and he was the ranger for the Estacada Ranger District!
I found it sad to read the comment "We just do not have that much institutional knowledge around anymore". But it doesn't surprise me.
Interesting reading. I hope the FS never tries to "improve" on these signs.
There's a short article about FS signs prior to these in this newsletter (see p. 10). Quite a bit of variation in the old days.
I learned a bit about Bus Carrell in a book that I have on the history of the FS in the PNW. He was responsible for dividing up the Estacada District into three smaller districts in 1952. He was in the district during WWII and noted that most of the district was closed to recreational use for security reasons in the early 1940s because of the Three Lynx power plant. We can relate to that with today's closure.
Here's a link to his essay: https://naldc.nal.usda.gov/download/IND43862108/PDF